Events

All future and past seminars

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Academic year 2023-2024

SPRING SEMESTER 2024

 

February 28 : Prof Marcelle Soares-Santos (Uni Zurich)

TitleDark Energy: recent results and the path for discovery in the era of multi-messenger studies - Slides

Abstract

This talk presents an overview of my research on dark energy with focus on recent developments towards incorporating gravitational wave standard sirens as a cosmological probe. Hypothesized as a new form of energy to explain the observed accelerated expansion of the universe, dark energy is one of the most formidable scientific problems of our time. Its discovery, in 1998, was awarded the physics 2011 Nobel prize, yet, its explanation remains elusive. My most well-known work is the DESGW project, which helped inaugurate the sub-field of multi-messenger cosmology with standard sirens. Rapid growth prospects in this area are fueled by the increased sensitivity of gravitational wave detectors and the discovery capability of cosmic survey instruments. Future prospects for this research program will likely include precision cosmological measurements to enable a breakthrough in our understanding of dark energy.

 

March 20: Dr. Andrii Tykhonov (DPNC)

Title: Recent observations in Galactic Cosmic Rays - Slides

Abstract

Observational data from space-borne experiments in the past decade challenge the canonical cosmic-ray theory. Recent results from AMS-02, DAMPE, and CALET missions have revealed unexpected, peculiar structures (in the form of breaks) in the hadronic and leptonic cosmic-ray spectra at multi-TeV energies. Some of those, like steepening in cosmic-ray positrons, can be arguably attributed to dark matter.  The situation is even more unclear at PeV scale, towards the so-called "knee" - the region, where the transition from galactic to extra-galactic cosmic ray origin is believed to emerge. Measurements performed by ground-based indirect experiments prevail at such energies, hampered by high systematic uncertainties. With the evolution of space-oriented particle instrumentation, we are experiencing an exciting era: cosmic-ray direct-detection experiments enter the traditional realm of ground-based observatories, approaching the "knee".

In this talk, first, we will briefly review the current state-of-the-art in galactic cosmic rays. Then we will dive into the recent experimental results of space-borne cosmic ray missions, complemented with the observations of ground-based facilities at higher energies. Finally, we will conclude with an outlook for future direct cosmic-ray measurements.

 

March 27: Dr. Giacomo Fedi (Imperial Colleague London)

Title: Data acquisition strategies in High Energy Physics: insights from the Tracker sub-detector of CMS for HL-LHC

Abstract

 The data acquisition system plays an important role in High Energy Physics experiments, responsible for handling significant data volumes that can present challenges for physics research. Within the CMS experiment, a blend of custom-designed and off-the-shelf electronics is employed to capitalize on their individual strengths, and this seminar will provide an overview of this approach. The upcoming new phase of the LHC in 2029, designed for higher luminosity (HL-LHC), necessitates updates to the CMS experiment's sub-detectors to address both the new data collection conditions and the aging of the current detector. This seminar offers insights into the specifics of data acquisition within the new Tracker sub-detector that will be installed as part of the CMS detector for the HL-HLC phase.

 

April 10 : Prof. Peter Križan (University of Ljubljana and J. Stefan Institute)

Title:  Belle II – status and recent results - Slides

Abstract

 The seminar will report on the results from the Belle II experiment. The detector has recently resumed taking data at the SuperKEK electron-positron collider after an upgrade of the vertex detector and several accelerator components. We will briefly introduce the experiment and report on the present status of the detector. We will discuss some exciting recent results, review the physics program of the experiment, and present the outlook.

 

April 24 : Prof Roberta Arcidiacono (INFN Torino)

Topic: Ultra-Fast Silicon Detectors

 

May 8: Prof. Marco Delmastro (CNRS Annecy, CERN)

Topic: Recent Higgs results at LHC and ATLAS

 

May 22: Prof. Piet Van Duppen (KU Leuven)

Topic:  Th-229 nuclear clock

 

May 29: Prof. Tobias Golling (UNIGE)

Topic: AI in High Energy Physics

 

 

AUTUMN semester 2023

 

September 20: Dr. Jenny List (DESY)

Title: LUXE: a new experiment to study non-perturbative QED and search for new particles in electron-laser and photon-laser collisions - Slides

Abstract

The LUXE experiment (Laser Und XFEL Experiment) is an experiment in planning at DESY Hamburg using the electron beam of the European XFEL. LUXE is intended to study collisions between a high-intensity optical laser pulse and 16.5 GeV electrons from the XFEL electron beam, as well as collisions between the laser pulse and high-energy secondary photons. This will elucidate quantum electrodynamics (QED) at the strong-field frontier, where the electromagnetic field of the laser is above the Schwinger limit. In this regime, QED is non-perturbative. This manifests itself in the creation of physical electron-positron pairs from the QED vacuum, similar to Hawking radiation from black holes. LUXE intends to measure the positron production rate in an unprecedented laser intensity regime. The experiment has received a stage 1 critical approval (CD1) from the DESY management and is finalising its technical design report (TDR). It is expected to start running in 2025/6. An overview of the LUXE experimental setup and its challenges and progress will be given, along with a discussion of the expected physics reach in the context of testing QED in the non-perturbative regime.

 

September 21: Prof. Subir Sarkar (University of Oxford)  SPECIAL SEMINAR  - 15:30  (attendance for the students is not mandatory but encouraged!)

Title: Forward Physics Facility: Connection to Astroparticle Physics

Abstract

High energy neutrinos have now been detected from the colliding beams at the LHC by the FASER and SND detectors. There is much exciting physics that can be done at the proposed FPF, which is of direct relevance to astroparticle physics experiments like IceCube and the Pierre Auger Observatory. I will discuss some relevant topics such as neutrino interactions, forward charm & light hadron production and searches for new particles beyond-the-Standard-Model.

 

October 4 : Dr. Alan Barr (Oxford)

TItle: Testing Bell Inequalities at the LHC - Slides

Abstract

Locality, reality and measurement have been central questions in Quantum Mechanics since its first formulation. Empirical tests addressing these issues were first proposed by John Bell in 1964. Subsequent experiments in atomic and optical systems (awarded the Nobel prize for physics 2022) have been found to agree with the quantum predictions at ~eV energies, and to disagree with local hidden-variable theories. I’ll discuss how, by exploiting developments from the field of quantum computing, we can now also conceive of extending these tests to high-energy systems such as Higgs boson decays.

 

October 18: Dr. Donatella Lucchesi (INFN Padova)

Title: Muon Collider: A Challenging Opportunity - Slides

Abstract
A multi-TeV muon collider represents both an exceptional discovery machine and an invaluable tool for achieving unparalleled precision in Standard Model measurements. Colliding elementary particles such as muons offers the advantage of having the entire nominal center-of-mass energy available for generating high-energy reactions, enabling the probing of extremely short length scales. Multi-TeV muons have a high probability of emitting electroweak radiation, effectively transforming the muon collider into a vector boson collider and unlocking novel avenues in physics research. However, the unstable nature of muons presents several significant challenges. A new method for beam cooling is needed and measures must be taken to shield both the machine and the detector from the high fluxes of particles generated by the interaction of muon decay products with infrastructure components. 
Addressing these technological challenges necessitates a systematic approach with a defined path. It starts with the of a demonstrator facility where the ionization cooling is proven. Subsequently, the construction of a machine operating at a center-of-mass energy of about 3 TeV, and eventually scaling to 10+ TeV, is foreseen. This phased research program promises to shed light on some of the most open questions in physics. The seminar will offer insights into the primary physics potentials alongside the associated experimental challenges, and it will provide an overview of the status of the collider facility.

 

November 1 : Dr.  Enrico Schioppa

Title: The quantum optics of gravitational waves - Slides

Abstract
In a very simplified way, accessible to anyone with a basic knowledge of quantum mechanics, I will show how quantum optics can be ported to the treatment of (hypothetical) quantum gravitational waves (GW). We will gain insights on the possibility of detecting a signature of the quantization of gravity with near-future GW interferometers.

 

November 15: Dr. Elias Roussos (Max Planck Institute)

TItle: The JUICE mission to Jupiter and the Particle Environment Package - Slides

Abstract

Jupiter Icy Moons Explorer (JUICE), launched on April 14th, 2023, is the first L-Class mission of ESA’s Cosmic Vision program that aims to make detailed observations of Jupiter of its three large ocean-bearing moons – Ganymede, Callisto and Europa. The mission, which is the first ever that will orbit a planetary moon other that of Earth, will characterise these worlds as both planetary objects and possible habitats, explore Jupiter’s complex environment in depth, and study the wider Jupiter system as an archetype for gas giants across the Universe. It will achieve this through a suite of remote sensing, geophysical and in situ instruments, one of which is the Particle Environment Package (PEP). PEP will measure charged and neutral particles in Jupiter’s magnetosphere and at the environments of its moons to answer how the planet’s corotating magnetosphere interacts with the complex and diverse environments of Europa, Ganymede, and Callisto. It will also identify and describe the governing mechanisms under which material is released into the Jovian magnetosphere by the volcanically active Io, and possibly Europa, an explore how internal and external solar wind drivers cause such energetic, time variable and multi-scale phenomena in the Jovian magnetosphere. To achieve this, PEP comprises six different instruments, each designed to measure particles across different regimes in energy, mass, ionization state and direction. Overall, PEP measures positive and negative ions, electrons, exospheric neutral gas, thermal plasma and energetic neutral atoms present in all domains of the Jupiter system over nine decades of energy from < 0.001 eV to > 1 MeV with full angular coverage. In this presentation, I will briefly describe the JUICE mission, the PEP instrument and its science, the measurement principles of its six different units, as well as several of its design challenges. I will also highlight the synergies between PEP and other instruments on JUICE, or even on Europa Clipper (NASA’s mission to Jupiter), that open up multiple pathways for interdisciplinary science.

 

November 29: Prof. Martín González-Alonso (IFIC Valencia)

Title: EFT analysis of neutrino, nuclear and collider physics - Slides

Abstract

Effective Field Theories (EFTs) have become a popular theory framework for the analysis of precision measurements. This approach allows one to connect and compare searches with very different characteristic energy scales. Its recent implementation in neutrino physics will be analysed. A few phenomenological applications will be discussed, such as coherent elastic neutrino-nucleus scattering (CEvNS), nuclear beta decay, electroweak precision observables in colliders, and neutrino oscillation data.

 

December 6 : Dr. Enrico Peretti (Paris APC)

Title: Ultra Fast Outflows from AGNs - Slides

 

December 8: Prof. Varun Bhalerao (Indian Institute of Technology)  SPECIAL SEMINAR  - 14:00 in GRAND AUDITURIUM!!! 

Title:  Daksha: On Alert for High Energy Transients

Abstract
Daksha is a proposed High Energy transients mission that will have higher sensitivity than any other mission in the world. Daksha will comprise of two satellites covering the entire sky from 1 keV to > 1 MeV. The primary objectives of the mission are to discover and characterize electromagnetic counterparts to gravitational wave sources; and to study Gamma Ray Bursts (GRBs). In addition, Daksha is a versatile all-sky monitor that can address a wide variety of science cases. With its broadband spectral response, high sensitivity, and continuous all-sky coverage, it will discover fainter and rarer sources than any other existing or proposed mission. Daksha can make key strides in GRB research with polarization studies, prompt soft spectroscopy, and fine time-resolved spectral studies.
 
Daksha will provide continuous monitoring of X-ray pulsars. It will detect magnetar outbursts and high energy counterparts to Fast Radio Bursts. Using Earth occultation to measure source fluxes, the two satellites together will obtain daily flux measurements of bright hard X-ray sources including active galactic nuclei, X-ray binaries, and slow transients like Novae. Correlation studies between the two satellites can be used to probe primordial black holes through lensing. Daksha will have a set of detectors continuously pointing towards the Sun, providing excellent hard X-ray monitoring data. Closer to home, the high sensitivity and time resolution of Daksha can be leveraged for the characterization of Terrestrial Gamma-ray Flashes.
 
In this talk, I will discuss the scientific impact of Daksha in all these areas. I will also give updates about the current mission status and future steps.
 
More details about the Daksha mission can be found at: https://www.dakshasat.in/for-astronomers

 

 

 

 

 

 

 

 

 

Academic year 2022-2023

Spring semester 2023

March 1st : Dr. Merlin Kole (UniGe)

Title: Studying the Universe through gamma-ray polarization - Slides

Abstract

 Gamma-Ray Bursts (GRBs) are the brightest explosions in the Universe. These phenomena are observed approximately once per day and consist of a bright flash of gamma-ray emission lasting of the order of seconds, followed by an afterglow emission which can be observed throughout the electromagnetic spectrum for days to months. Thanks to the study of thousands of these events we now know that they are extra-galactic and the result of the deaths of massive stars or the merger of neutron star binaries. Despite having a good idea of what causes GRBs, many open questions remain about the physics at play within them. For example, the origin of the gamma-ray emission remains highly debated until today. Two new fields which will allow to answer these questions have emerged in the last decade. These are multi-messenger astrophysics and gamma-ray polarimetry. The POLAR-2 mission, developed here at the University of Geneva, will play an important role in both these fields. It will perform the first precise gamma-ray polarization measurements from astrophysical sources, which will allow it to answer a range of questions on GRBs. Secondly, this instrument which will be launched in 2025, will send alerts to ground based instruments like CTA, to allow for quick follow-up observations of GRBs in other wavelengths. In this talk I will present the large variety of activities we are involved in for the POLAR-2 project. Firstly, I will discuss the development of the POLAR-2 mission and the unique science this instrument can do on its own. In addition, I will present the role the instrument will play in multi-messenger astrophysics, specifically in connection to gravitational wave astronomy and through its unique machine learning based alert system.

 

 

 

 

 

 

 

 March 15 : Dr. Michela Marafini (Università Roma 1)

Title: News from Radio and Particle Therapy against tumours: the flash effect and the potential of the almost empty (or full?!) - Slides

 

Abstract

 Over the past decades, research in radio and particle therapy (RT, PT) has been focused on the goal to enhance the therapeutic ratio by maximising the tumour control while minimising damage to the healthy tissue. Recent advances in therapy with electrons with ultra-high dose rate (>40 Gy/s) delivered in a short treatment time (<500 ms) through narrow (order of μs), high dose (~1Gy) pulses, have shown a new potential way to increase the therapeutic ratio, that is a reduction in healthy tissue damage while preserving tumour control. This new effect has been named FLASH effect. The great interest around the experimental evidence of the FLASH effect has led to an intense research activity on the development of monitoring techniques for charged beams at ultra-high dose rates. FLASH poses an unprecedented challenge since the performances of conventional detectors are usually compromised by non-linear effects due to the very high flux of particles.

The FlashDC (Flash Detector beam Counter) exploits the air fluorescence to target the monitor in real time of the beam fluency and possibly also the spatial distribution with high accuracy and minimal impact on treatment delivery. According to literature data this mechanism could provide a linear response for any charged beam and in a wide range of dose rates and energies.

Several prototypes have been developed for proof-of-principle studies. The latest results, obtained irradiating the monitor with an electron FLASH beam delivered by the ElectronFlash LINAC at CPFR (Pisa, Italy), provided strong indication that fluorescence is linearly correlated with the relevant parameters under study, in particular with the dose delivered within each micro-pulse.

The developed monitors have been designed with optimised geometry using a FLUKA Monte Carlo simulation. The background evaluation studies plays a crucial role in the detector design.

In this presentation, after an introduction on FLASH effect, the FlashDC monitor will be presented together with the expected performances and the results obtained with electron beam arrogated in FLASH modality.

 

 

 

 

 

 

 March 22 : Dr. Magdalena Kowalska (CERN/UniGE)

Title: From atomic parity violation and magnetisation distribution in nuclei to biological studies with unstable nuclei at the ISOLDE facility at CERN - Slides

Abstract

The parity non-conservation of the weak interaction manifests itself, among others, in the anisotropic beta decay of an ensemble of polarised nuclei. At our setup located at ISOLDE, which is CERN’s factory of short-lived nuclei, we use beta-decay asymmetry as a basis of an extremely sensitive nuclear magnetic resonance approach, beta-NMR, in which the inefficient signal detection via inductive pickup is replaced by beta-event counting.  

Our experiments have already allowed to increase the accuracy in determining the magnetic moments of short-lived nuclei by over 2 orders of magnitude. We are now building on this achievement to increase the precision in the atomic-parity violation (APV) studies. We aim to achieve this goal by determining with unprecedented precision the distribution of magnetisation in atomic nuclei, which is the largest uncertainty in QED calculations that are needed to interpret APV experiments.  

On the side of applications, we have pioneered the use of beta-NMR on very short nuclei in biological studies, such as the binding of alkali metals to DNA. At present, in collaboration with Uni Mainz and HUG we are extending chemistry and biology applications of beta-NMR to longer-lived isotopes known from Positron Emission Tomography (PET) in zero-to-ultra-low fields (ZULF-NMR), to which we will apply polarisation techniques known from NMR on stable-nuclei.   

In this talk, I will explain the physics behind beta-detected NMR, I will present the elements of our experimental setup, and will provide details about the magnetisation-distribution and biology-oriented studies. 

 

 

 

 

 

 

 

CANCELLED (DATE CHANGE) March 29 : Dr. Juan Cortina (CIEMAT - Spain)
Title:Cherenkov Telescopes: the highest photon energies, the highest angular resolution

!!! Moved to May 3 !!!

 

April 5 : Prof. Stefania Beolé

Title: The evolution of the ALICE Inner Tracking System - Slides

Abstract

 The ALICE Inner Tracking System (ITS) has been replaced with a full silicon-pixel detector constructed entirely with CMOS monolithic active pixel sensors.
It consists of three inner layers (50 mm thick sensors) and four outer layers (100 mm thick sensors) covering 10 m2 and containing 12.5 billion pixels with a pixel size of 27 μm x 29 μm.
Its increased granularity, the very low material budget (0.35% X0/layer in the inner barrel) as well as a small radius of the innermost layer combined with a thin beam pipe, will result in a significant improvement of impact-parameter resolution and tracking efficiency at low pT with respect to the previous tracker.
Exploiting the flexibility of silicon when thinned down to thicknesses of O(50um), and the possibility of producing MAPS sensors of wafer size by a process known as stitching, the ALICE project is aiming at building detector elements that are large enough to cover full tracker half-layers with single bent sensors.
R&D on all project aspects (incl. technology verification, mechanics for bent wafer-scale devices, test beams of bent MAPS, design of stitched sensors) is rapidly progressing with the aim for installation during LHC LS3.
In this talk, the first results of the performance of the new ALICE ITS detector will be presented, together with an overview of the ITS3 R&D status.

 

 

 

 

 

 

 April 19 : Prof. Stephane Paltani (UniGE)

Title: Exploring the Dark Universe with EUCLID - Slides

Abstract

 EUCLID is the next astrophysics mission of the European Space Agency, which will be launched in July this year. EUCLID's main science question is the nature of dark energy. In this talk, I will recall the main open questions in observational cosmology, as well as the main cosmological probes, with a focus on those that EUCLID will use. Switzerland is very significantly involved in EUCLID, with the center of mass being very clearly at UNIGE, with DPT and ASTRO. ASTRO in particular has made, and is still making, important contributions to the mission itself, by developing a piece of hardware, developing crucial analysis algorithms and hosting one of the ten EUCLID science data centers. I will describe the expected science of EUCLID, focusing on those that are enabled by our contributions.

 

 

 

 

 

 

May 3 : Dr. Juan Cortina (CIEMAT - Spain)
Title: Cherenkov telescopes: the highest photon energies, the highest angular resolution - Slides

Abstract

Imaging atmospheric Cherenkov telescopes are the telescopes with the largest optical mirrors in the world and the fastest photodetectors. Their primary goal is the study of the universe at photon energies above few GeV. I will review how the technique has opened the sky in this energy range during the last decades thanks to instruments such as MAGIC, and how the field is expected to profit from the next generation instrument CTA. I will illustrate the potential of CTA with the newest results of its first telescope on site, the LST1 in La Palma. What is more, the design of Cherenkov telescopes also enable them as intensity interferometers. In this alternative mode of operation, they detect photons in the visible range but with an angular resolution below 1 miliarcsecond, allowing studies of stars and their surroundings such as winds and disks. I will show how we are applying this second technique in MAGIC and how we propose to extend it to CTA, and I will speculate on future initiatives. 

 

 

 

 

 

May 17 : Prof. Eric Zimmerman  (Colorado University )
Title: Designing and understanding modern neutrino beams - Slides

 

Abstract

 Accelerator-based neutrino beams are at the heart of many recent advances in physics, and will be key to making progress in the future. These beams have evolved into major facilities whose design, construction, operation, and analysis form a lively subfield within experimental high-energy physics. This seminar will describe the physics and design principles behind a neutrino beam, as well as the analysis challenges associated with these beams and new experimental effort to solve them.

 

 

 

 

 

 

May 24 : Dr. Paul Laycock (Brookhaven National Laboratory)
Title: Computing in High Energy Physics - Highlights and Future Trends - Slides

Abstract

 The International Conference on Computing in High Energy and Nuclear Physics, or CHEP, addresses computing challenges of data-intensive science at the exabyte scale using worldwide computing resources.  The conference provides an opportunity for some 500 experts to share their ideas and discuss the various challenges related to massive-scale computing that needs to run constantly improving software on ever-evolving (and ever-more heterogeneous) hardware.  It is also an opportunity to establish collaborations, and the last decade has seen a concerted effort to work together both across High Energy and Nuclear Physics domains, and beyond, particularly with the Astronomy and Astrophysics communities.  The common computing solutions embodied by the Worldwide LHC Computing Grid (WLCG) and the common software efforts nurtured by the HEP Software Foundation (HSF) have attracted growing interest, thereby providing a potential basis for sustainable, cross-cutting scientific computing for the coming decades.  Highlights of the CHEP 2023 conference (https://www.jlab.org/conference/CHEP2023) will be presented, together with a personal view about what the future of scientific computing may bring.

 

 

 

 

 

AUTUMN semester 2022

September 21 : Prof. Michele Doro (University of Padova, Department of Physics and Astronomy) -- in zoom

Title: Some topics of fundamental physics attainable with IACTs Slides

Abstract

Astrophysical gamma rays in the TeV regime are valid probes of new physics because of the high energies, large distances and/or times involved in the processes. The program of current ground-based imaging atmospheric Cherenkov telescopes (IACTs) on fundamental physics is wide: from the search of particle dark matter annihilation or decays (heavy and light) or other proposed exotic objects such as magnetic monopoles or quark nuggets, to that of signatures of new physics such that coming from Lorentz Invariance violation theories or involving tau neutrinos. This ample and complex program runs for more than a decade now within HESS, MAGIC and VERITAS, the current major IACTs, in strong competition with the astrophysical observation program. In this presentation, I will discuss some of these topics, arguing on the lessons learnt and the things to come for CTA and other future facilities. 

 

October 12 : Dr. Sofia Vallecorsa  (CERN)                
Title: CERN QTI: initial results and research perspective on Quantum Computing for HEP- Slides

Abstract

CERN launched a Quantum Technology Initiative in 2020 in order to investigate the use of quantum technologies in High Energy Physics (HEP). A three-years roadmap and research program has been defined with the HEP and quantum-technology research communities. In this context, a range of projects, set up at CERN in collaboration with HEP institutes worldwide, have explored the use of Quantum Computing, and Quantum Machine Learning algorithms, on different use cases which are representative of the next generation LHC experiments computing challenges. When reaching the end of the QTI second year, a set of preliminary results were gathered, outlining benefits, constraints and limitations of introducing quantum algorithms. These learnings will be used to feed into  the definition of a long-term research plan, closely aligned with the technological development of quantum infrastructure. This talk will summarize the experience accumulated through the past years, outline the research results and provide an initial perspective of future directions.

 

November 2 : Dr. Susanne Kuehn  (CERN)                 
Title: The Tracking detectors of the ATLAS and CMS experiments for the High-Luminosity LHC - Slides

Abstract

In the high-luminosity era of the Large Hadron Collider, the instantaneous luminosity is expected to reach unprecedented values, resulting in about 200 proton-proton interactions in a typical bunch crossing. To cope with the resultant increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk), aiming to provide tracking coverage up to |η|<4. Similarly, the CMS experiment will install a new tracking detector for operation at the HL-LHC. Beside the challenge of radiation hardness and high-rate capable silicon sensors and readout electronics many system aspects have to be considered for fully functional detectors. An overview of the concept and technology choices for the upgrade trackers will be presented. Mechanical and electrical results will be highlighted from various prototyping and pre-production efforts with an emphasis on the ITk of the ATLAS experiment. Moreover, performance estimates and a comparison of the detectors will be presented.

 

November 9 : Prof. Anna Soter  (ETH Zurich)                         
Title: Precision particle physics with exotic atoms and antimatter

Abstract

Despite the immense success of the Standard Model (SM), it is well known to be incomplete in describing Nature. Most obviously it is not incorporating gravity, and also falling short in explaining cosmological observations like the baryon asymmetry of the Universe, or the nature of dark matter and dark energy. In the recent years, tensions within the SM as well arose, especially concerning lepton universality with the latest result from LHCb [1], or from the muon g-2 experiment [2].

 

In this talk, precision particle physics efforts at the Paul Scherrer Institute (PSI) are introduced in the lepton sector, with the focus on two novel experiments, both exploring beyond-SM physics, but using rather different methods and physics processes.

 

PIONEER is a newly formed international collaboration, where we are searching for potential violations of lepton flavor universality by investigating branching ratios of the charged pion decay to electrons against to muons, a number precisely predicted by the Standard Model [3].

 

In the LEMING experiment we aspire to carry out next generation atomic physics and gravity experiments using muonium, which is an exotic atom consisting of a muon and an electron (M = μ⁺ + e⁻) [4]. We started this challenging task by developing a novel cold atomic M beam in vacuum using muon conversion in superfluid helium, based on a curious inert behavior of exotic atoms in the quantum liquid [5]. The new tantalizing results with the cold M beam production put us on a path for increased precision in 1S-2S laser spectroscopy of M, and may pave the way for a free fall experiment, that would be the first direct measurement of the gravitational interaction using (anti-)leptons.

  

References

 

       [1]     LHCb Collaboration, Nat. Phys. 18, 277–282 (2022)

       [2]     Muon g−2 Collaboration, Phys. Rev. Lett. 126, 141801 (2021)

       [3]     PIONEER: Studies of Rare Pion Decays, arXiv:2203:01981

       [4]     A. Soter and A. Knecht, SciPost Phys. Proc. 5, 31 (2021)

       [5]     A. Soter et. Al Nature 603, pages 411–415 (2022)

 

November 16 : Prof. Boisvert Veronique (Royal Holloway, University of London)   
Title: The Climate Emergency: can Particle Physics ever be sustainable? - Slides

Abstract

We live in a climate emergency and consequently all countries are putting in place measures to reduce their carbon emissions in order to reach a so-called “net zero emissions” by 2050. All aspects of economic life will be affected by such measures, including particle physics research. I will present some examples of sources of carbon emissions within the field of particle physics. This will include emissions associated with building and running accelerators, detector operations, high-performance computing and activities associated with our research life like travel. I will also present solutions being developed for addressing this in the near and long term as well as recommendations for the field. 

 

November 23 : Dr. Alex Winkler  (Detection Technology PLC, Finland)                      
Title: Detectors for more than science, but based on science - Slides

Abstract

Radiation detectors with cutting edge technology are designed and build by CERN research groups, in order to extend our knowledge on the mysteries of the universe and life itself. The CP asymmetry of the B mesons as a display of the matter-anti-matter imbalance in the universe, indicates that there is a lot to discover with potentially new physics. Some of the technologies developed for CERN experiments are used in applications that make our daily life easier, more safe and even safe our lives. This seminar will provide a short history of the detector technologies that were first employed at CERN, but are now used all around us, followed by an outlook of latest technologies that are finding their way in our daily world as well.

 

November 30 : Dr. Raffaele Tito D'Agnolo, IPhT, France
Title: Sliding Naturalness: A New Solution to the Strong-CP and Electroweak Hierarchy Problems - Slides

Abstract
 I will discuss the first joint solution to the strong-CP and electroweak hiearachy problems. At low energy it extends the Standard Model by two axion-like scalars and predicts correlated signatures in neutron EDM and fuzzy dark matter searches.

 

 

December 7 : Prof. Radoslav Marcewski (EPFL)                       
Title: Kaon physics strikes back - Slides

Abstract
Kaon physics has proven to be an important branch of particles physics leading to many tantalizing discoveries over the past decades. Kaon observables were essential to our understanding of quark interactions and the establishment of the Standard Model as the dominant particle physics theory. Furthermore, rare kaon processes offer a precision test of the Standard Model by probing heavily suppressed loop processes with large sensitivity to various Beyond the Standard Model scenarios.
The NA62 experiment at CERN collected the world`s largest data set of charged kaon decays in 2016-2018, leading to the first measurement of the Branching ratio of the ultra rare K+ -> pi+nu nubar decay. This decay was observed with a significance of 3.4 standard deviations, based on 20 candidate events. The measurement also sets limits on BR(K+ -> pi+X), where X is a salar or pseudo-scalar particle. The analysis of the 2018 data sample and the future NA62 plans and prospects are reviewed.
Future initiatives for experiments in the kaon sector at the intensity frontier require technological innovations and present a compelling physics case. In this seminar the High Intensity Kaon Experiments (HIKE) proposal is discussed, aimed at collecting a large amount of kaon decays after LS3, as well as other new and exiting experimental opportunities for the far future. 

 

 

December 14 : Prof. Francesco Salamida  (Università degli Studi dell'Aquila)         
Title: UHECRs at the Pierre Auger Observatory - Slides

Abstract

In the new scientific era of multi-messenger astronomy, ultra-high-energy cosmic rays offer a very rare opportunity to investigate the nature of astro- physical sources and particle interactions at energies far from current particle accelerators capabilities. With almost 20 years of operation, the Pierre Auger Observatory is the world’s largest cosmic ray detector providing a unique data set of the most energetic particles in the Universe. The Observatory employs a hybrid technique: a Surface Detector consisting of 1660 Water Cherenkov detectors and covering an area of 3000 km2 and 27 Fluorescence telescopes. A review of selected results is presented, focusing on the energy spectrum, mass composition measurements, search for sources, neutral particles and fundamental physics. The future prospects of the Observatory will also be discussed in light of the AugerPrime upgrade currently under construction.

 

Academic year 2021-2022

SPRING semester 2022

March 2 : Prof. François Grey, CUI, UniGe, CH
Topic: Citizen Science - Slides

Abstract

Kyiv, Covid, Climate Change and Crowdsourcing

The evolving role of citizen science in global crises

François Grey, Centre Universitaire d’Informatique

Citizen science is a term used over the last few decades to describe a range of methodologies that enable citizens to contribute data to science projects. Citizen science projects are often led by professional scientists in academic institutions. They may involve just a few participants or thousands of citizens at a time. They may run for just a few weeks or for decades. Increasingly, they depend on digital technologies, such as phone-based apps or web-based games, to gather, analyze and simulate new data.

Citizen Cyberlab is a partnership with CERN and UNITAR based at the Centre Universitaire d’Informatique. Since 2009, Citizen Cyberlab has initiated a series of citizen science projects as well as developed new digital tools and practical methodologies for collaboration between citizens and scientists. At Citizen Cyberlab, we take a broad view of citizen science, and include a range of digital crowdsourcing activities that may not have a direct scientific objective, but which can nevertheless generate data of scientific importance. A particular focus is on citizen-generated data of relevance to National Statistical Offices that are tracking progress towards the UN Sustainable Development Goals (SDGs).

In this talk, I will focus on new trends in citizen science, where crowdsourcing technologies, often combined with artificial intelligence, enable citizens to contribute to tackling major crises. Examples I will describe include: open source intelligence used to document rapidly unfolding crises, such as the war in Ukraine; the roles of amateur scientists and crowdsourcing in tracking the origins and understanding the spread of Covid; how young people, inspired by the Fridays for Future movement, are using collaborative citizen science methodologies to gather data about climate change and its impacts, as well as to develop solutions for climate resilience and adaptation.

In the case of climate change, I will be illustrating examples from Crowd4SDG, an EU project that UNIGE leads, in collaboration with the Citizen Cyberlab partners CERN and UNITAR as well as partners in Barcelona, Milan and Paris.

 

 

March 16 : Dr. Kate Shaw, Univ. Sussex, UK
Title: Widening the talent pool in physics - Slides

Abstract

What if the next Curie or Einstein is a student in a country where scientific research and education is not a priority? Physics has historically been a field accessible only to a small minority of people, often in the richer countries around the world. To widen the talent pool available to science, the scientific community must be more reflective of the diversity of humankind. This means students from countries without strong scientific research centres or access to advanced training and opportunity must be given access through our wider scientific community. This talk will look at diversity and inclusion in physics, within nations and across the globe, and look at initiatives to ensure the brightest minds have access to opportunity and training.

 

March 30 : Dr. Jamie Boyd, CERN, CH
Title: The Forward Physics Facility at the HL-LHC - Slides

Abstract

High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe Standard Model (SM) processes and search for physics beyond the Standard Model (BSM). FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. The seminar will outline the FPF physics motivations, and the status of ongoing studies on the facility design and proposed experiments.

Further reading: https://arxiv.org/pdf/2203.05090.pdf

 

April 13 : Dr. Lorenzo Paolozzi, UniGe, CH
Title: Fast monolithic silicon pixel detectors in SiGe BiCMOS: the path to picosecond time resolution - Slides

Abstract

The monolithic integration of silicon pixel detectors in a CMOS process is a flexible and low-cost solution to manufacture tracking detectors for ionizing radiation with excellent space resolution and low material budget. The research team at the University of Geneva pioneered the integration of pixel sensors in commercial SiGe BiCMOS, making the first monolithic pixel detector with a time resolution below 100ps. This technology is now established, with the first applications being the new preshower detector of the FASER experiment at the LHC and a high-granularity scanner for Positron Emission Tomography. The new great challenge is the production of a detector that combines picosecond time resolution and state-of-the art tracking capability. The MONOLITH ERC Advanced project aims at producing the first silicon pixel detector with picosecond time resolution, using the concept of the Picosecond Avalanche Detector (PicoAD). Such a device would be groundbreaking for high-energy physics experiments, medical physics and commercial applications.

 

 

April 27 : Prof. Ivan De Mitri, GSSI, Italy
Title: Recent observations on High Energy Cosmic Rays - Slides

Abstract

The study of High Energy (HE) and Ultra-High Energy (UHE) cosmic rays is currently being driven by new and very interesting data from both space-borne and ground-based experiments. The talk will be devoted to a review of recent observations of electrons/positrons, protons/antiprotons, and nuclei, at energies above tens of GeV. New techniques and mission concepts will also be briefly discussed.

 

May 5: Dr. Christian Ohm - KTH, Stockholm, Sweden
Title: Long-lived particles at the LHC: Spectacular signatures and delayed discoveries? - Slides

Abstract
The Standard Model of particle physics has been frustratingly successful at predicting and describing experimental results at collider experiments for decades. Nonetheless, it suffers from several severe shortcomings that indicate that it is incomplete and needs to be extended. These beyond-SM extensions can give rise to a broad range of experimental signatures, and I will discuss the challenging phenomenology of long-lived beyond-SM particles and how we search for them at the LHC. I'll highlight several recent results and discuss ideas for future strategies in Run 3 of the LHC which is just starting.

 

May 10 : Prof. Jure Zupan, U. Cincinnati, US ** Unusual time: 16:15

Title: The quest for light new physics - Slides

Abstract

If light new physics states are produced in some of the laboratory experiments  this will give us a window to dynamics at very high scales, possibly all the way up to 10^12 GeV, depending on the process. I will illustrate this  on several well motivated examples of new physics models leading to light states. Special attention will be paid to the rare flavor experiments, which can probe complementary parameter space relative to the beam dump experiments and astrophysical systems.

 

May 18 : Dr. Pasquale Blasi, GSSI, Italy
Title: Transport of cosmic ray hadrons and leptons: status and perspectives - Slides

Recent measurements of the spectra of cosmic ray species (nuclei, electrons, antimatter) have revealed several new aspects of the problem of the origin of cosmic rays, that are expected to shed light on the microphysics responsible for the transport of cosmic rays in the Galaxy. After a pedagogical introduction to some basic aspects of the theory of transport of charged particles in magnetized plasmas I will establish possible connections with current observations and emphasise success and critical aspects of the current understanding of these phenomena. The non-linear aspects of cosmic ray transport, that have recently been subject of much investigation, will be granted special attention as observations suggest their important role in both particle acceleration (maximum energy, magnetic field amplification) and propagation (diffusion suppression around sources and TeV halos).

 

June 1 : Dr. Nick Rodd, CERN, CH
Title: Searching for the Heaviest Particle in the Universe - Slides

Abstract

If dark matter is a particle with a mass between the electroweak and Planck scale, we could detect it through its decays to high-energy cosmic rays. Testing this hypothesis requires a detailed understanding of the astrophysics of where these decays are occurring and the particle physics that dictates the spectra of produced cosmic rays. In this talk, I will describe recent progress on both fronts. On the astrophysics side, searches within our own Milky Way halo can significantly outperform extragalactic observations, and I will demonstrate how this insight allows for a definitive statement to be made about a longstanding decaying dark-matter anomaly, the 3.5 keV X-ray line. On the particle physics side, I will outline how to perform a field theory calculation at energies approaching the Planck scale, and show how working with the full unbroken Standard Model produces dark-matter spectra that differ by orders of magnitude from previous estimates.

AUTUMN semester 2021

 

Sep. 15 : Bruno Mesnet (IBM systems), Dr. Filip Leonarski (PSI), Dr. Lionel Clavien (InnoBoost)

Title : At last a new and proven technique to push the limits of our old conventional CPU-centric servers by adopting memory coherence! - Slides 1, Slides 2, Slides 3, Slides 4, Slides 5

 

Sep 22 : Dr. Massimo Passera - INFN, Padua
Title: Muon g-2 and Δα connection - slides

Abstract

The Muon g-2 experiment at Fermilab has recently confirmed Brookhaven's earlier measurement of the muon anomalous magnetic moment a_μ. This new result increases the discrepancy Δa_μ with the Standard Model (SM) prediction and strengthens its "new physics" interpretation. On the other hand, a recent lattice QCD result weakens this discrepancy. In this talk I will review the SM prediction of the muon g-2, focusing on some of the latest developments, and discuss the connection of the discrepancy Δa_μ to precision electroweak predictions via their common dependence on hadronic vacuum polarization effects. I will also briefly present the recently proposed MUonE experiment at CERN, where fixed-target muon-electron scattering will provide a new direct determination of the leading hadronic contribution to the muon g-2.

 

Sep. 28 : Prof. Tae Min Hong (U. Pittsburgh * Seminar on Tuesday 16:15
Title :  Invisible Higgs decays & trigger challenges at the LHC - slides

Abstract

With more data coming from LHC collisions, detailed measurements of Higgs boson properties allow us to probe whether it communicates with the unknown and/or undiscovered sector beyond the Standard Model. One motivation is weakly interacting dark matter, which are invisible to the detecting apparatus, through a Higgs portal. I will discuss the latest ATLAS results of the search for Higgs bosons decaying to invisible particles. I will also describe the technical challenges of triggering on such events using missing energy from the Higgs boson decay and/or hadronic jets from the Higgs boson production, including the potential use of machine learning methods on FPGA boards in real-time level-1 trigger systems.

 

Oct 13 : Dr Andrea Zani, INFN, Milan
Title: Prototyping DUNE - The first beam run of ProtoDUNE-SP and plans for a second run - Slides

Abstract

The ProtoDUNE Single Phase (SP) detector is one of two ton-scale prototypes built at CERN as testbeds for the design validation of the upcoming DUNE far detector modules.

DUNE is a next-generation, multi-kton neutrino detector based on Liquid Argon Time Projection Chamber (LArTPC) technology; among its main physics goal are the precise measurement of the neutrino oscillation parameters, as well as the collection of neutrinos from astrophysical sources and the search for BSM physics.

Given DUNE dimensions, featuring four far detectors with a total mass of 17 kton each, it becomes fundamental to develop a strong and layered R&D program, that will bring the LArTPC technology to the next level, for safe employment during the long life-time of DUNE (10-20 years).

ProtoDUNE is the natural result of this R&D program. A kton detector allows testing all aspects of the technology to be deployed in DUNE, with full-scale components; it permits to characterize new solutions and materials to be employed; it works as the perfect training ground for detector installation, operation; it allows the development on real data of algorithms for acquisition, reconstruction, and analysis.

Building and operating ProtoDUNE SP in around 2 years was an incredible challenge carried out by the DUNE collaboration. Its success allowed the evolution of the design for the DUNE first far detector module, and interesting performance and physics results are being produced. This seminar will cover the construction and first beam run of ProtoDUNE SP; it will present the initial physics results obtained from the data collected, and finally it will give insight into the upcoming second beam run, which will see the deployment of new upgraded detector components.

 

Oct 20 : Dr Anja Butter, ITP, Heidelberg

Title: Machine Learning for LHC Theory - Slides

Abstract

Over the next years, measurements at the LHC and the HL-LHC will provide us with a wealth of data. The best hope of answering fundamental questions like the nature of dark matter, is to adopt big data techniques in simulations and analyses to extract all relevant information.
On the theory side, LHC physics crucially relies on our ability to simulate events efficiently from first principles. In the coming LHC runs, these simulations will face unprecedented precision requirements to match the experimental accuracy. Innovative ML techniques like generative models can help us overcome limitations from the high dimensionality of the parameter space. Such networks can be employed within established simulation tools or as part of a new framework.
At the analysis level, machine learning methods have already shown impressive performance boosts for instance in top tagging and jet calibration. While neural networks offer an attractive way to numerically encode functions, actual formulas remain the language of theoretical particle physics. Symbolic regression trained on matrix-element information provides optimal LHC observables in an easily interpretable form.

 

Oct 27 : Dr. Simon Spannagel - DESY

Title : Allpix Squared - Silicon Detector Monte Carlo Simulations for Particle Physics and Beyond - Slides

Seminar also in person, at the Grand Auditoire, École de Physique.

Abstract

Allpix Squared is a versatile, open-source simulation framework for
silicon pixel detectors. Its goal is to ease the implementation of
detailed simulations for both single sensors and more complex setups
with multiple detectors. While originally created for silicon detectors
in high-energy physics, it is capable of simulating a wide range of
detector types for various application scenarios, e.g. through its
interface to Geant4 to describe the interaction of particles with
matter, and the different algorithms for charge transport and
digitization. The simulation chain is arranged with the help of
intuitive configuration files and an extensible system of modules, which
implement the individual simulation steps. Detailed electric field maps
imported from TCAD simulations can be used to accurately model the drift
behavior of charge carriers, and an implementation of the Shockley-Ramo
theorem enables time-resolved signal formation studies, adding a new
level of detail to Monte Carlo simulations of particle detectors.

Recently, Allpix Squared has seen major improvements to its core
framework to take full advantage of multi- and many-core processor
architectures for simulating events fully parallel. Furthermore, new
sensor geometries such as hexagonal pixels have been introduced, further
extending the application range. This seminar provides an overview of
the framework and its components, highlighting the versatility and some
of the recent developments.

 

 Nov 3 : Dr. Vava Gligorov - LPNHE
Title: Real-time analysis at 30 MHz — the LHCb experience - Slides

Abstract

What does it mean to analyse terabytes of data per second in real time? What kind of computing architectures must we master to achieve such a goal? How do we write code which gives compatible results at the permille level across a range of computing architectures? How do we build teams of physicists and software specialists with highly heterogeneous skills and keep them working together for a decade in order to achieve these objectives? If those sound like interesting questions you will find some personal reflections on them, based on a decade of development within the LHCb collaboration, in this talk.

 

Nov 17 : Prof. Paolo Crivelli, ETHZ
Title: “The NA64 experiment searching for dark sectors at the CERN SPS " - Slides

Abstract

"NA64 is a fixed target experiment using the unique CERN SPS secondary beamlines to search for hidden sectors.  The experiment looks for new particles such as dark photons, axion-like particles, new light X or Z’ bosons by colliding 100-150 GeV energy electron beams onto an active target. I will present the NA64 experiment and report the latest results emphasizing the sensitivity of our experiment to search for possible new physics contributions in muon anomalous magnetic moment. I will conclude with the future prospects of the experiment which just resumed data taking this Summer after the 2 years CERN long shutdown.”

 

Dec 1 : Dr Davide Pinci , INFN, Roma
Title: The CYGNO experiment: a gaseous optically readout TPC for rare events - Slides
studies

Abstract

The possibility of studying low energy events produced by weakly
interacting particles is becoming crucial in many aspects of
astroparticle physics, from the search of possible Dark Matter
candidates to solar neutrino spectroscopy.
The CYGNO collaboration is developing a gaseous TPC, operated at
atmospheric pressure and room temperature, where the light produced
during the multiplication process in the channels of a triple-GEM stack
is acquired by a system composed by CMOS optical sensors and
photo-multipliers.
This technology provides a set of information (energy released and its
space profile, 3D direction and 3D position) that allows to reconstruct
and identify ionisation produced in the gas by electronic or nuclear
recoils with energies down to few keV with the aim of the construction
of a 1 cubic meter demonstrator to be installed underground at the Gran
Sasso Laboratories.

In this presentation, the results obtained with different prototypes,
with a particular emphasis on the measurements performed with the 50
litres one, will be presented together with the studies about the
sensitivities in different physics research applications.

 

Dec 22 : Prof. Maurice Bourquin, Unige

Title: Comment détruire les déchets des centrales nucléaires - Slides

!!! special Xmas seminar !!!

Abstract

Transmutex SA est une entreprise privée, fondée en 2019 à Genève, qui vise à développer une nouvelle technologie d'énergie nucléaire permettant de « brûler » les déchets nucléaires existants tout en produisant une énergie décarbonée. Ce procédé a été démontré au CERN par le professeur Carlo Rubbia (prix Nobel 1984), puis confirmé par de nombreuses études.

Pour accélérer son développement, dans le but de lutter plus efficacement contre les changements climatiques, nous avons réuni les meilleurs centres de recherches et sociétés dans le domaine, incluant l’Institut Paul Scherrer en Suisse. De plus, Transmutex vise à acquérir de Russie la licence d'un réacteur nucléaire unique au monde, ayant propulsé les sous-marins soviétiques de classe Alfa, tenant du record de vitesse en immersion.

 

Jan 12 : Prof Raffaele Flaminio, CNRS/IN2P3

Title: Technical challenges in ground based laser interferometers for gravitational wave detection - Slides

Abstract

The first detection of gravitational wave events achieved by the LIGO-Virgo collaboration has open the field of gravitational wave astronomy. After the detection of the first merger of a binary black hole in 2015 and the observation of the first binary neutron star in 2017, during the O3 run gravitational wave transients have been recorded at a rate of one per week. Gravitational wave detectors are based on laser Michelson-type interferometers with arms several km in length. The detection of the events requires measuring variations in the arm length of the order of 10 -18 m. At this level of sensitivity tiny effects like thermal noise in the mirrors of the interferometer and quantum noise due to the Heisenberg principle play an important role. Moreover, the detector has to be perfectly shielded from environmental disturbances due to seismic and acoustic noise. To this purpose the interferometers are hosted inside some of the largest vacuum systems in the world and their mirrors are suspended to the most efficient seismic isolators available on Earth. In this talk I will give an overview of the technical challenges that LIGO and Virgo had to face to achieve the required sensitivity as well as the ones in front of us to realize more sensitive detectors like the Einstein Telescope.

 

Jan 19 : Dr Kathrin Valerius , KIT
Title: Probing the neutrino mass: latest results from KATRIN

Abstract

Precision measurements of the kinematics of weak decays offer a direct and mostly model independent approach to probe the absolute neutrino mass scale. The KArlsruhe TRItium Neutrino experiment (KATRIN) is searching for the minute imprint of the neutrino mass in the endpoint region of the tritium β-decay spectrum. KATRIN employs a high-intensity gaseous molecular tritium source and a high-resolution electrostatic filter with magnetic adiabatic collimation to target a neutrino-mass sensitivity of 0.2 eV based on five years of data.

With its initial two science runs already, KATRIN has substantially improved kinematic neutrino mass bounds – recently achieving the first direct constraint at sub-eV sensitivity. In addition, KATRIN has begun to address further science channels such as the direct search for light sterile neutrinos. As larger data sets are collected and further improvements in terms of signal-to-background ratio and systematics are being achieved, KATRIN is continuing its exploration of the sub-eV neutrino mass parameter space and its search for BSM physics in precision β-decay spectroscopy.

 

Feb 9 : Dr Valentina Cairo, CERN
Titel: Probing the Higgs self-coupling with the ATLAS Detector at the LHC - Slides

Abstract

The post-Higgs discovery era has been characterized by an exciting physics program targeting the investigation of the Higgs boson properties and couplings. The Higgs self-coupling, which determines the shape of the Higgs potential, is one of the building blocks of the Standard Model of Particle Physics, directly connected to the electroweak symmetry breaking mechanism.

Probing the self-coupling is among the most important goals of the High-Luminosity phase of the Large Hadron Collider (LHC) experiments, but much can already be learned from the available Run 2 dataset and from the upcoming Run 3 data taking expected to start in 2022.

This talk will describe the state of the art of direct tests of the Higgs self-coupling with the ATLAS experiment via Higgs pair production, with emphasis on the

 

Feb 22 : Dr Kazuhiro Terhao, SLAC * Seminar on Tuesday 16:15
Topic: ML in LAr - Slides

 

 

SPRING semester 2021

March 3 : Prof. Elisa Resconi - TUM, Germany
Title: New direction in high energy neutrino physics: IceCube and the Pacific Ocean Neutrino Experiment

Abstract

Abstract: A higher statistics of high energy neutrinos is needed to open the universe's exploration at the highest energies. In this talk, I will address questions related to the nature of dark matter, the existence of long-lived exotic particles, and how cosmic laboratories can accelerate particles at least up to the PeV scale. The availability of
multi-cubic-kilometer neutrino telescopes currently limits the advance. In this talk, I will discuss the field's status and new opportunities to collect more and better measured high energy neutrinos. To this end, I will cover IceCube and the planned Upgrade and the future neutrino telescopes IceCube-Gen2 and the Pacific Ocean Neutrino Experiment.

 

 

March 16 : Dr Ben Nachman - LBNL, USA * Seminar on Tuesday 16:15
Title: Modeling final state radiation on a quantum computer - slides

Abstract

Particles produced in high energy collisions that are charged under one of the fundamental forces will radiate proportionally to their charge, such as photon radiation from electrons in quantum electrodynamics. At sufficiently high energies, this radiation pattern is enhanced collinear to the initiating particle, resulting in a complex, many-body quantum system. Classical Markov Chain Monte Carlo simulation approaches work well to capture many of the salient features of the shower of radiation, but cannot capture all quantum effects. We show how quantum algorithms are well-suited for describing the quantum properties of final state radiation. In particular, we develop a polynomial time quantum final state shower that accurately models the effects of intermediate spin states similar to those present in high energy electroweak showers. The algorithm is explicitly demonstrated for a simplified quantum field theory on a quantum computer.  At the end of the talk, I will discuss how techniques from high energy physics can also improve measurements on quantum computers using unfolding algorithms. 

 

April 14 : Dr. Prasenjit Saha - Univ. of Zurich, CH
Title : Next-generation optical interferometry and the return of Hanbury Brown and Twiss - slides

 

April 28 : Prof. Enrique Kajamovitz - Technion, Israel * postponed
Title : Searching for Muonic Force Carriers with ATLAS

Abstract
Muonic Force Carriers are a possible manifestation of Physics Beyond the Standard Model. These new particles have flavor-specific couplings, they couple to the Standard Model only through muons, and could be part of Dark Matter or act as mediators between the Standard Model and a Dark Sector. Muonic Force Carriers potentially explain the persistent inconsistency in the muon anomalous magnetic moment. 
In this talk, we will discuss how the ATLAS experiment can be used as a muon-beam fixed target experiment to search for Muonic Force Carriers. 

 

May 5 : Prof. Florian Piegsa - Univ. of Bern, CH
Title : Fundamental Particle Physics with Neutrons - slides

Abstract

The neutron represents a versatile tool in the realm of fundamental particle physics. It is often used to perform precision physics measurements at low energies with the goal to search for beyond standard model signals. In this seminar, I will introduce a few activities currently pursued at the University of Bern. The projects comprise the hunt for a CP-violating neutron electric dipole moment using a pulsed beam, the search for axions as dark matter candidates and the development of a high-sensitivity interferometer which shall ultimately be used to measure the neutron's electric charge.

 

May 12 : Dr Andrea Celentano - INFN Genova, Italy
Title : POKER: POsitron resonant annihilation into darK mattER - slides

Abstract
Light dark matter is the new compelling hypothesis that identifies dark matter with new sub-GeV “Hidden Sector” states, neutral under Standard Model interactions and interfacing with our world through a new force. Accelerator-based searches at the intensity frontier are uniquely suited to explore it. However, current efforts are either limited by the low sensitivity or the high backgrounds. This calls for a major breakthrough in the field.
 
The goal of POKER is to establish and demonstrate a new approach to search for light dark matter, based on a missing energy measurement with a positron-beam, active thick-target setup.
The new technique, based on light dark matter production through positron annihilation on atomic electrons, is characterized by a larger signal yield compared to previously explored reactions, and by a unique signal signature resulting from the underlying reaction dynamics: a peak in the missing energy distribution. 
The final objective of the project, approved as a 1.5 M€ ERC Starting Grant for 2020-2025, is to perform a pilot run with the 100 GeV positron beam available at the H4 beamline at CERN, to demonstrate the technique by exploring a so-far unknown territory in the Hidden Sector parameters space.
 
In this seminar, after a brief introduction the Hidden Sector physics case, I’ll first discuss the potential of accelerator-based light dark matter efforts. I’ll then present the POKER experiment, focusing on the active thick target - the key element of the project. I’ll finally show the sensitivity of POKER to different Light Dark Matter scenarios.

 

May 19 : Prof. Gino Isidori - Univ. of Zurich, CH
Title : B-physics anomalies and the flavor problem - slides

Abstract
Recent data in semileptonic B-meson decays indicate a coherent pattern of 
deviations from the Standard Model. I critically review these data and discuss their interpretation, both in terms of a generic effective-theory approach and in terms of more complete extensions of the Standard Model. I will discuss in particular how present data points toward some new dynamics not far from the TeV scale, possibly by linked to the origin of the flavor hierarchies. Implications for future measurements both at low and high-energies are also briefly discussed.

 

May 26 : Dr. Andreas Hoecker - CERN
Title: Ultimate precision Standard Model tests: the muon magnetic moment — taming hadronic contributions - slides

Abstract

Elementary particles with spin behave like tiny magnets with magnetic moments that can be measured and predicted extremely precisely for the electron and the muon. These moments receive contributions from quantum fluctuations, which — in the case of the muon — may involve new, heavy particles not yet directly observed at particle accelerators. A recent precise measurement of the muon magnetic moment at Fermilab confirmed a longstanding discrepancy, now reaching 4.2 standard deviations, with the theoretical prediction. That prediction is dominated by difficult to compute contributions from hadronic quantum fluctuations. The seminar will review the status of the magnetic moment measurements, their theory predictions, and then focus on the challenges of the hadronic contributions. 

 

June 15 : Prof. Jonathan Feng - UCI, USA * Seminar on Tuesday 16:15
Title: FASER and the Forward Physics Facility at CERN  - slides

Abstract

For decades, the focus of searches for new particles at the LHC has been on heavy particles and high pT.  Recently, however, new ideas have led to novel opportunities for discovery in the far-forward region with relatively fast, small, and cheap experiments. These include FASER, which has recently been installed at the LHC, and FASERnu, which has recently opened up a new window on neutrinos at TeV energies.  In this talk, I will give an overview of the physics motivations, including both Standard Model and new physics; describe FASER and FASERnu and their current status; and present a new proposal for a Forward Physics Facility at CERN.

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