COMPASS is the longest-running experiment at CERN, with a record-breaking 20 years of data collection from 2002 to 2022. The experiment has a unique and diverse physics programme focused on nucleon structure and spectroscopy measurements.
This talk will review selected highlights from the COMPASS legacy on parton transverse momentum dependent nucleon spin structure studies and address...
The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is the world's only polarized proton collider with center-of-mass energies up to 500 GeV and polarizations of about 60% for each proton beam. It provides unique opportunities to study the spin structure in hadronic systems and opens new kinematic regions compared to deep inelastic scattering. The three pillars of the...
The status of several CLAS12 semi-inclusive deep inelastic scattering measurements sensitive to TMDs, including several new results from a 10.5 GeV longitudinally polarized electron beam incident on a longitudinally polarized target, will be discussed. A focus will be placed on areas where CLAS12 and other fixed target experiments may be in friction with phenomenology, including effects from...
Generalized Parton Distributions (GPDs) are nowadays the object of an intense effort of research, in the perspective of understanding nucleon structure. They describe the correlations between the longitudinal momentum and the transverse spatial position of the partons inside the nucleon and they can give access to the contribution of the orbital momentum of the quarks and gluons to the nucleon...
Deeply Virtual Compton Scattering (DVCS) and Hard Exclusive Meson Production (HEMP) are valuable processes to study Generalized Parton Distributions (GPDs). By correlating the longitudinal momentum of the partons to their transverse spatial distribution inside the nucleon, GPDs reveal the 3-dimensional structure of the nucleon in QCD. Following a test run in 2012, exclusive measurements were...
SpinQuest, a fixed-target experiment at Fermilab, studies the Drell-Yan process by utilizing transversely polarized NH₃ and ND₃ targets alongside an unpolarized 120-GeV proton beam. The primary goal is to measure single spin azimuthal asymmetries that arise from the correlation between the transverse momentum of the struck quark and the spin of the parent nucleon, referred to as Sivers...
We present an analysis to extract kaon parton distribution functions (PDFs) using meson-induced Drell-Yan and quarkonium production data. Starting from the statistical model, first developed for describing the partonic structure of nucleons and later applied to the pion, we have extended this approach to perform a global fit to existing kaon-induced Drell-Yan and charmonium production data....
The proton charge radius is one of the pivotal quantities in physics. In particular, its value is highly correlated with the experimental determination of the Rydberg constant. For the past seventy years it has been measured through elastic electron-proton scattering and ordinary hydrogen spectroscopy methods. Over the years, results from both methods generally agreed with each other within...
In this talk, I will highlight recent semi-inclusive deep inelastic scattering (SIDIS) studies carried out at Jefferson lab to probe hadronization mechanisms and associated medium modifications of the underlying structure of atomic nuclei, with a focus on the first-ever SIDIS Lambda production in the current and target fragmentation regions. These new results, alongside the lately collected...
The initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV will be presented. The proposed physics program encompasses a large and diverse range of transforamtive investigations centered around the non-perturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon...
The goal of LHCspin is to develop innovative solutions and cutting-edge technologies to advance the field of spin physics over the next few years, by exploring a unique kinematic regime and exploiting new reaction processes. To achieve this, a polarized gaseous target, operated in combination with high-energy, high-intensity LHC beams and the highly performing LHCb particle detector, has the...
Many of the physicists working in this field were not alive in 1974 and many others have not heard of the November Revolution. We give that name to an event at the SLAC Auditorium on November 11, 1974 when teams from Brookhaven and SLAC announced the remarkable results that heralded the discovery of the fourth quark, charm. This discovery led, very quickly, to the Standard Model of Particle Physics.
I will discuss several processes involving J/psi production which would allow for the extraction of gluon TMDs in present and future experiments at the LHC and the EIC.
The Drell-Yan process is an important probe of TMD densities at high energy. In this contribution, we present the status of phenomenology based on TMDs computed in the Parton Branching Method, comparing the predictions to experimental results up to LHC energies. We demonstrate that existing measurements are sensitive to the inner proton structure and highlight the role of TMD evolution.
In this contribution, I will present a determination of unpolarised charged pion and kaon fragmentation functions (FFs) from a set of single-inclusive electron-positron annihilation (SIA) and lepton-nucleon semi-inclusive deep-inelastic scattering (SIDIS) data. The determination is carried out in a framework that combines a neural-network parametrisation of fragmentation functions with a Monte...
The status of the implementation of spin effects in the Pythia hadronization via the StringSpinner package is reviewed. The package is then used for simulations of e+e- annihilation, and the resulting Collins asymmetries for back-to-back hadrons are shown and compared with the BELLE and BABAR data. The Collins analyzing power resulting from the string+3P0 model is extracted and compared to...
In this opening talk, I will discuss the status of TMD studies, focusing on some recent developments and some open aspects
Building on the concluded study of ART23,
we provide a simultaneous fit to DY and SIDIS data,
constraining both TMDPDFs as well as TMD fragmentation functions.
I will discuss the challenges and status of the project, including (preliminary) results.
A deeper understanding of the three-dimensional structure of nucleons requires separating how different flavours contributes to transverse momentum distributions. We present an initial step in this exploration, with the latest results by the MAP Collaboration on the extraction of unpolarized quark Transverse Momentum Dependent Distributions and Fragmentation Functions from global fits of...
The main aspect of factorization relies on both the universality of the distributions as well as their interpretations as describing the internal structure of the hadrons. We present a novel approach which is best suited for hadron structure studies as it is built to both satisfy theoretic constrains originating from their operator definitions, as well as clearly demarcating the perturbative...
Searching for the onset of Color Transparency (CT) is a vibrant experimental effort to observe hadrons in a small neutral transverse size configuration in the nucleus. The observation of the onset of CT lies at the intersections between the quark-gluon degrees of freedom and the nucleonic descriptions of nuclei. CT is fundamentally predicted by quantum chromodynamics and is expected to be...
High-energy reactions on nuclei are conveniently described using light-front quantization. I discuss how especially in tagged processes on the deuteron, the light-front densities of the polarized deuteron enter. I discuss their properties (of relevance to polarized measurements) and some similarities to partonic TMDs.
I will review the main particle candidates to constitute the dark matter in the Universe. I will discuss the state-of-the-art searches of some of the candidates both with accelerator experiments and with astrophysical techniques.
One of the indirect detection method of dark matter (DM) is based on the search of the products of DM annihilation or decay. They should appear as distortions in the gamma rays spectra and in the rare Cosmic Ray (CR) components, like antiprotons, positrons and antideuterons, on top of the standard astrophysical production. In particular, the antiprotons in the Galaxy are mainly of secondary...
The Beam Dump Experiment (BDX) at Jefferson Laboratory (JLAB) is electron-beam thick-target experiment to search for Light Dark Matter (LDM) particles in the MeV-GeV mass range. BDX will exploit the high-intensity 10.6 GeV e beam from CEBAF accelerator impinging on the beam dump of experimental Hall-A, collecting up to 10^22 electrons-on-target in a few years time. Any LDM particles produced...
I will review the current status of meson spectroscopy, with particular focus on exotic candidates. I will discuss the theory and analysis tools that are commonly used to calculate the spectrum and to compare with data, both in the light and heavy sector.
A vast number of new hadrons have been discovered in recent years, a large proportion of them by Belle and LHCb. Many of these new hadronic states do not fit into the traditional quark model, and their nature is yet to be understood. Progress in this field requires advances both in theory and experiment. This contribution presents recent results in heavy hadron spectroscopy from Belle II and LHCb.
Recently, numerous excited states have been observed in heavy hadron decays and beam experiments, with some interpreted as exotic candidates beyond the traditional three-quark model. In this talk, I will provide a brief overview of the recent progress in strange baryon spectroscopy and introduce a new experiment utilizing a GeV-photon beam at SPring-8/LEPS2.
Photoproduction of hadrons is an important experimental tool to understand the generation of hadrons as bound systems of quarks and gluons in the non-perturbative regime of QCD. The GlueX experiment, which is located in Hall D of Jefferson Lab, uses an intense photon beam with energies of up to 12 GeV that is incident on a liquid hydrogen target. A large acceptance spectrometer with...
The Facility for Antiproton and Ion Research (FAIR) in Darmstadt has begun installing accelerator components and will soon begin commissioning. The main driving synchrotron the SIS100 will provide a wide range of beams, including an intense proton beam with up to 30 GeV/c. Currently, the physics potential to expand the program of the CBM detector to include measuring exclusive final states...
An introduction on the study of exclusive processes in hadron-hadron colliders will be given. This will be followed by results of measurements of exclusive processes at the LHC. Where applicable, parallels with measurements in lepton-hadron interactions will be highlighted.
In my talk, I will focus on the problem of model dependency affecting the phenomenology of generalized parton distributions (GPDs). I will argue that a lot of useful information on nucleon structure can already be accessed from the amplitudes of exclusive processes, particularly thanks to recently developed techniques based on Froissart-Gribov projections. Another way to avoid model dependency...
Measuring Deeply Virtual Compton Scattering (DVCS) on the neutron is one of the necessary steps to understand the structure of the nucleon in terms of Generalized Parton Distributions (GPDs). Neutron targets play a complementary role to transversely polarized proton targets in the determination of the GPD E. This poorly known and poorly constrained GPD is essential to obtain the contribution...
Lorentz invariance violation (LV) can be examined through the time delay between high-energy and low-energy photons in gamma-ray bursts (GRBs). Previous studies determined the Lorentz violation energy scale as $E_{\rm LV} \simeq 3.60 \times 10^{17}$~GeV using Fermi Gamma-ray Space Telescope (FGST) data. We update the time delay model and reaffirm these findings with new observations.
New method is presented for measuring the radius of the deuteron that can help to resolve the current discrepancies between muon-deuteron, electron-deuteron spectroscopic as well as electron-deuteron scattering measurements.
The MUon proton Scattering Experiment (MUSE) at the Paul Scherrer Institute (PSI) was motivated by the proton radius puzzle. We obtain simultaneous high-precision measurements of elastic electron-proton and muon-proton scattering, alternating between positively and negatively charged leptons. The experiment will test lepton universality by comparing electron to muon scattering, will determine...
The form factors of the energy-momentum tensor give information on the pressure, energy and angular momentum distributions among quark and gluons inside the proton. We discuss the distributions of pressure and angular momentum inside a quark state dressed with one gluon.
The SPD experiment will operate at one of the two interaction points of the NICA collider facility at JINR. The collider will provide polarized proton and deuteron beams for $pp$ and $dd$ collisions with the c.m.s. energy up to $\sqrt{s} = 27$ GeV and $\sqrt{s_{NN}} = 13.5$ GeV, respectively. The primary goal of the experiment is to study the polarized and unpolarized gluon structure of proton...
A new Monte Carlo generator for simulation of the events with unobservable hard photon including the exclusive radiative tail in semi-inclusive deep inelastic scattering of polarized particles is presented. Simulation strategy, structure of the contributions to the observed cross section, cross-checks are presented and briefly discussed.
Transverse Momentum Dependent Parton Distribution Functions (TMDPDFs) can be extracted from deep processes such as Drell-Yan (DY), Semi Inclusive Deep Inelastic Scattering (SIDIS), and $e^+$ $e^-$ annihilation. At the leading-twist, there are two time-reversal odd TMDPDFs, namely the Sivers function and the Boer-Mulders function have connections to the partons' orbital angular momenta...
In recent years, AI/ML techniques have become common practice in particle physics experiments. In this talk, I will review how AI/ML is used in the CLAS12 experiment at Jefferson Lab, to enhance its capabilities in online monitoring, triggering, reconstruction efficiency, and data analysis.
In this talk, an overview of the physics program, the detector conceptual design, and the project status will be presented. The Electron-Ion Collider in China (EicC) is a proposed high energy nuclear physics facility to be constructed based on the High Intensity heavy-ion Accelerator Facility (HIAF) in Huizhou, China. EicC will be able to place highly polarized ($\sim$80%) electrons in...
The proposed super tau-charm facility (STCF) is a symmetric electron-positron collider, designed to provide $e^+e^−$ interactions at a center-of-mass energy from 2.0 to 7.0 GeV. This energy region corresponds to the transitions between non-perturbative quantum chromodynamics (QCD) and perturbative QCD. Hence, a large variety of topics in elementary particle physics can be pursued at STCF,...
The transverse momentum squared $P_T^2$ distributions of charged hadrons produced in deep inelastic scattering and the azimuthal modulations in their angular distributions provide valuable insight into the transverse motion of partons. Using unpolarized semi-inclusive deep inelastic scattering data collected by the COMPASS Collaboration in 2016 and 2017 on proton target with longitudinally...
Semi-inclusive deep inelastic scattering (SIDIS) measurements provide crucial experimental insight into the three-dimensional momentum structure and spin structure of nucleons. The additional degree of freedom when observing two hadrons in the semi-inclusive final state allows for access to correlations between quark polarization and the angular momentum of final state hadrons through Dihadron...
One of the main objectives of extensive physics program of COMPASS experiment has been to conduct measurements of target-spin asymmetries in semi-inclusive (di-)hadron production in Deep Inelastic Scattering of high-energy muons off polarized targets. In 2022, the latest semi-inclusive DIS measurements were performed using a transversely polarized deuteron target and a 160 GeV/c muon beam....
Relevant information about hadron structure is contained in nonperturbative functions called Transverse Momentum Depentend Parton Distribution Functions (TMD PDFs) and the Collins-Soper kernel, a universal function which regulates their scale evolution.
Usually these functions are obtained by modeling and fitting to experimental data but in recent years lattice calculations have calculated...
We present the preliminary results for the Collins and Sivers amplitudes of the transverse target spin asymmetries (TSAs) in production of neutral kaons ($K^0$) in semi-inclusive deep inelastic scattering. The results were obtained using the data accumulated at COMPASS in 2022 on a transversely polarized $^6$LiD target. The amplitudes were extracted using an unbinned maximum likelihood...
The investigation of Transverse-Spin Dependent Azimuthal Asymmetries in the Drell-Yan process provides a key insight into the spin-dependent structure of nucleons, particularly testing the restricted universality of Transverse-Momentum Dependent Parton Distribution Functions. During the 2015 and 2018 data-taking periods, the COMPASS Collaboration at CERN measured the $\pi^-$p $\rightarrow...
Advancements in precise neutrino experiments offer promising opportunities to explore new physics by examining the effects of Neutral Current Non-Standard Interactions between neutrinos and matter. While neutrino oscillation experiments have already imposed stringent limits on all vector NC NSI flavor elements, axial NC NSI remains elusive in these studies. However, neutrino-nucleon scattering...
