With the full Run 2 pp collision dataset collected at 13 TeV, very detailed measurements of Higgs boson properties and its interactions can be performed using its decays into bosons and fermions, shining light over the electroweak symmetry breaking mechanism. This talk presents the latest measurements of the Higgs boson couplings by the ATLAS experiment in various decay channels, including...
A study of different jet observables in high $Q^{2}$ Deep-Inelastic Scattering events close to the Born kinematics is presented. Differential and multi-differential cross-sections are presented as a function of the jet’s charged constituent multiplicity, momentum dispersion, jet charge, as well as three values of jet angularities. Results are split into multiple $Q^{2}$ intervals, probing the...
To calculate the PDFs from first principles in Lattice gauge theories
it is convenient to consider the Ioffe-time distribution defined through gauge-invariant bi-local operators with spacelike separation.
Lattice calculations provide values for a limited range of the distance separating the bi-local operators. In order to perform the Fourier transform and obtain the pseudo- and the...
In this talk we present the NNPDF4.0 global analysis. As compared to its predecessor, NNPDF3.1, the new NNPDF4.0 fit includes 44 new datasets, mostly from the LHC, benefits from a novel machine learning methodology based on hyperparameter optimisation and stochastic gradient descent, is based on state-of-the-art NNLO QCD calculations, and accounts for NLO electroweak corrections and nuclear...
In semi-inclusive deep inelastic scattering (SIDIS) the non-zero transverse momentum of partons is reflected in the transverse momentum $P_T$ of the produced hadrons and in their azimuthal distribution. Assuming Gaussian dependence of transverse momentum dependent (TMD) PDFs and fragmentation functions (FFs) upon quark transverse momentum, exponential distribution of $P_T^2$ is expected. For...
In this talk we present the most recent extraction of unpolarized transverse-momentum-dependent (TMD) parton distribution functions (PDFs) and TMD fragmentation functions (FFs) from global data sets of Semi-Inclusive Deep-Inelastic Scattering (SIDIS), Drell-Yan and Z boson production. The fit is performed at the (next-to)$^3$ leading logarithmic accuracy in the resummation of qT-logarithms and...
With the pp collision dataset collected at 13 TeV, detailed measurements of Higgs boson properties can be performed. The Higgs kinematics and CP properties can be measured with various production and decay modes and interpreted to constrain beyond-the-Standard-Model phenomena. This talk presents the measurements of Higgs boson differential and fiducial cross-sections as well as their...
The internal structure of jets allows us to bridge our description and understanding of short-distance physics and color confinement. In this talk, we discuss recent measurements of jet substructure performed using data collected by the CMS experiment at a center-of-mass energy of √s=13 TeV. Measurements of various jet substructure observables, with and without jet grooming, are presented. The...
MSHT20 is the latest PDF fit from the MRST/MSTW/MMHT/MSHT collaboration, representing our most accurate and precise determination of the PDFs to date it is designed for the LHC precision era. We present a general review and outline further progress which has been made. This includes the effects of varying the strong coupling α_S (M_Z^2) and the masses of the charm and bottom quarks. We...
In this talk the current status and plans are presented on the LHeC, towards the new HEP strategy update in about 5 years time, on physics, with emphasis on the $eh-hh$ relation, on the machine, especially the IR, and further detector developments. The talk also covers FCC-he and refers to a separate presentation of the ERL facility PERLE. It is based on the comprehensive Conceptual Design...
We perform the fit to the structure function F2 data from HERA including terms due to the resummation at small x. The equation for the unintegrated gluon density is solved, previously established within the renormalization group improved small x framework. We find very good description of the structure function F2 and its charm component Fc2. The resulting unintegrated gluon density is found...
One of the simplest extensions of the Standard Model (SM) Higgs sector is the Higgs singlet extension in which one adds a singlet to the particle content of the SM. Such models are being studied at the LHC. In the simplest realization of this model, in which the singlet is real, there are two Higgs bosons and only three new parameters, two mixing angles and the mass of the additional Higgs...
Calculations for processes involving a high multiplicity of coloured particles often employ a leading colour approximation, where only the leading colour levels in the expansion of the number of colours Nc are calculated and subleading colour levels, which are suppressed by powers of 1/N^2_c relative to the leading colour, are omitted. This approximation of the full colour result is motivated...
We present our theoretical results of the next-to-leading order approach (NLO) of [Eur. Phys. J. C 80, 1029 (2020)] in contrast with the experimental HERA data. This approach includes the re-summed NLO corrections to the kernel of the evolution equation, the correct asymptotic behavior in the NLO at $\tau = r^{2}Q_{S}^{2} \gg 1$; the impact parameter dependence of the saturation scale in...
We discuss recent developments in the global QCD analysis of parton distribution functions by CTEQ-TEA collaboration.
We present our recent results published in 10.1140/epjc/s10052-022-09997-1. The azimuthal correlation of high transverse momentum jets in pp collisions is studied by applying PB-TMD distributions to NLO calculations via MCatNLO together with the PB-TMD parton shower. A very good description of the cross section as a function of the di-jet azimuthal separation is observed. In the back-to-back...
A central ingredient in calculations of scattering processes in the high energy saturation regime of QCD is the light cone wavefunction. It is a universal QCD quantity encoding the light cone gauge partonic structure of a high energy projectile, and a necessary ingredient in cross section calculations for different scattering processes. This talk will report on the recent calculation of the...
Motivated by recent progress in the PDF determinations carried out by the CT, MSHT, and NNPDF groups, we present an updated combination of global PDF fits: PDF4LHC21. It is based on the Monte Carlo combination of the CT18, MSHT20, and NNPDF3.1 sets followed by either its Hessian reduction or its replica compression. Extensive benchmark studies are carried out in order to disentangle the origin...
In the Standard Model, the ground state of the Higgs field is not found at zero but instead corresponds to one of the degenerate solutions minimising the Higgs potential. In turn, this spontaneous electroweak symmetry breaking provides a mechanism for the mass generation of nearly all fundamental particles. The Standard Model makes a definite prediction for the Higgs boson self-coupling and...
The development of a TeV-scale muon accelerator and storage ring provides enormous scientific potential not only for a $\mu^+\mu^-$ collider, but also for deep inelastic scattering in a completely new regime when a TeV muon beam is collided with a hadron beam. For example, if the approved Electron-Ion Collider at BNL were eventually upgraded with a TeV muon beam replacing its low energy...
Extending TMD factorization to thrust-dependent observables entails difficulties ultimately associated with the behavior of soft radiation. As a consequence, the definition of the TMDs has to be revised, while keeping (and extending) its universality properties. Moreover, the regularization of the rapidity divergences intertwines with the thrust dependence, leading to a new kind of...
We investigate the proposal by Kharzeev and Levin of a maximally entangled proton wave function in Deep Inelastic Scattering at low x and the proposed relation between parton number and final state hadron multiplicity. Contrary to the original formulation we determine partonic entropy from the sum of gluon and quark distribution functions at low x, which we obtain from an unintegrated gluon...
The HERAPDF2.0 ensemble of parton distribution functions (PDFs) was introduced in 2015. The final stage is presented, a next-to-next-to-leading-order (NNLO) analysis of the HERA data on inclusive deep inelastic $ep$ scattering together with jet data as published by the H1 and ZEUS collaborations. A perturbative QCD fit, simultaneously of $\alpha_S(M_Z^2)$ and and the PDFs, was performed with...
The lepton-jet momentum imbalance in deep inelastic scattering events offers a useful set of observables for unifying collinear and transverse-momentum-dependent frameworks for describing high energy Quantum Chromodynamics interactions. A recent first measurement was made [1] of this imbalance in the laboratory frame using positron-proton collision data recordedf with the H1 experiment at HERA...
The discovery of the Higgs boson with the mass of 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable to solely explain some observations. Many extensions of the Standard Model addressing such shortcomings introduce additional Higgs-like bosons which can be either neutral or...
Recently a multi-jet merging method has been proposed which incorporates the evolution of TMD distributions [arXiv:2107.01224 [hep-ph]]. We present new studies of differential jet rates in this framework, and results for Drell-Yan (DY) production and multijets. We discuss the reduction of merging scale uncertainties owing to the TMD merging compared to collinear merging, and investigate the...
The CEBAF accelerator at Jefferson Lab has been providing polarized electrons for high-impact nuclear and particle physics experiments for almost three decades. Accelerator upgrades providing polarization of the beam, increasing the beam energy, and increasing number of experimental end stations have paved the way to many new and successful experiments conducted at the lab. Studies are...
The LHCb detector at the LHC offers unique coverage of forward rapidities. The detector also has a flexible trigger that enables low-mass states to be recorded with high efficiency, and a precision vertex detector that enables excellent separation of primary interactions from secondary decays. This allows LHCb to make significant (and world-leading) contributions in these regions of phase...
Possibilities for the measurement of the longitudinal structure function in diffraction FDL at the future US Electron Ion Collider are investigated. The sensitivity to FDL arises from the variation of the reduced diffractive cross section with centre-of-mass energy. Simulations are performed with various sets of beam energy combinations and for different assumptions on the precision of the...
Measurement of inclusive untagged and heavy-flavour jet production in pp
collisions provides an important test of perturbative QCD and can help to
improve Monte Carlo generators. Jet measurements in p-Pb collisions enable
the study of cold nuclear effects, including the nuclear modification of the PDF.
Jet grooming algorithms reduce nonperturbative effects by removing soft wide-
angle...
COMPASS is a fixed target high energy physics experiment located at the M2 beamline (SPS, North Area) at CERN. The experiment is collecting data since 2002 covering a broad range of physics topics. Experimental results obtained by COMPASS for spin (in)dependent azimuthal azimuthal effects in semi-inclusive deep inelastic scattering (SIDIS) measurements, play an important role in the general...
The goal of LHCspin is to develop, in the next few years, innovative solutions and cutting-edge technologies to access spin physics in polarised fixed-target collisions at high energy, exploring the unique kinematic regime offered by LHC and exploiting new final states by means of the LHCb detector. The forward geometry of the LHCb spectrometer is perfectly suited for the reconstruction of...
Recent progress in global analyses have led to pressing questions about precision and accuracy. NNLO PDFs must balance between the precision of experimental constraints and robustness (stability) with respect to the choice of experimental sets and methodological assumptions. We critically compare various strategies for achieving this balance in the Hessian and Monte Carlo formalisms adopted by...
The study of the partonic and spin structure of the nucleon, using semi-inclusive measurements of hadron muoproduction in Deep Inelastic Scattering (DIS), is one of the main objectives of the COMPASS experiment at CERN. Within the QCD parton model approach, the nucleon structure in DIS can be parametrized in terms of Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs),...
We present a QCD analysis of Drell-Yan W and Z cross-sections using a wide range of measurements from the RHIC, Tevatron and LHC colliders, together with the Deep Inelastic Scattering data from the HERA-2 collider. The study is performed using the xFitter framework and employs a consistent set of theoretical predictions at NNLO in QCD and NLO in EW couplings. Predictions using modern PDFs are...
The study of the dense gluonic matter emerging in QCD at high energies represents one of the main goals of the experimental program at the future Electron-Ion Collider. We demonstrate that dijet production via inelastic diffraction is a promising channel for probing gluon saturation, including in the hard regime at high photon virtuality, where the collinear factorisation applies. By...
We report on calculations of differential cross sections for $c \bar c$- and $b \bar b$-dijet production in $pp$-scattering at $\sqrt{s} = 13$ TeV in the $k_T$-factorization and hybrid-factorization approaches with different unintegrated parton distribution functions (uPDFs). We present distributions in transverse momentum and pseudorapidity of the leading jet, rapidity difference between the...
The Future Circular Collider with electron-positron beams (FCC-ee) will provide improvements of the precision measurement concerning Z, W, H, and top by a large factor over the present status. High precision with the run at the Z pole, where the instantaneous luminosity is expected to be five to six orders of magnitude larger than LEP, offers considerable improvements of the strong coupling...
The presence of a non-baryonic Dark Matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If Dark Matter interacts weakly with the Standard Model (SM) it could be produced at the LHC. The ATLAS experiment has developed a broad search program for DM candidates, including resonance searches for the mediator which would couple DM to the SM,...
Jet-like correlation measurements involving heavy-flavour hadrons allow for comparisons of their production, propagation, and hadronization across different collision systems. Comparison of measurements performed in pp and p-Pb collisions can help to study the possible modification of the heavy-quark production and hadronization inside jets due to cold-nuclear-matter effects, while possible...
We present the MCscales approach for incorporating scale uncertainties in parton
distribution functions. The method builds on the Monte Carlo sampling method
for propagating experimental uncertainties to PDFs that underlies the NNPDF
approach, by extending it to the space of factorisation and renomalisation
scales for the processes entering a PDF fit. A prior probability is assigned...
The search for gluon saturation is one of the main pillars for the scientific program of the future Electron-Ion Collider (EIC). In recent years, significant progress has been made in advancing saturation physics to a precision science as we prepare for the EIC era. We contribute to these efforts by performing the first complete next-to-leading order (NLO) computation of inclusive dijet...
Various theories beyond the Standard Model predict new, long-lived particles with unique signatures which are difficult to reconstruct and for which estimating the background rates is also a challenge. Signatures from displaced and/or delayed decays anywhere from the inner detector to the muon spectrometer, as well as those of new particles with fractional or multiple values of the charge of...
Nowadays the study of hadron's structure is triggering ambitious efforts, both on the theretical and experimental side. The advent of new facilities such as the EIC or the EIcC is expected to be shed light on many of the still open questions about hadron’s complexity. This work takes advantage of the such situation to perform the first systematic feasibility study of accessing generalised...
One of the most common final state resulting from high-energy particle collisions features collimated sprays of hadrons. These so-called hadronic jets can be seeded
by particles with very different properties (e.g. from fragmentation, and subsequent hadronization, of very energetic partons or from the hadronic decays of heavy particles, such as the Higgs boson etc). Therefore, the correct ...
We present a general formalism for the inclusion of theoretical uncertainties from missing higher orders into a parton distribution function (PDF) fit. We demonstrate how using the currently available knowledge about the next-to-next-to-next-to-leading order (N$^3$LO), an order above the standard NNLO used in current PDF fits, can provide consistent, justifiable and explainable estimates for...
Using the spinor helicity formalism we calculate the one-loop corrections to inclusive di-hadron production in DIS at small $x$ using the Color Glass Condensate description of the target proton or nucleus. It is shown that all divergences either cancel or can be absorbed into evolution of hadron fragmentation functions. We discuss phenomenological applications of our results to EIC and...
We study the impact of the inclusion of a light baryonic boson B (which we henceforth refer to as a dark photon), primarily coupled to quarks, as a constituent of the proton; this is achieved by including a dark photon parton distribution function (PDF) in the standard PDF evolution equations. Depending on the proposed mass and coupling of the dark photon, the evolution of light quark and...
Understanding the transverse spin and momentum structure of the proton is of great interest to the nuclear physics community and it is one of the main goals of the spin physics program at the Relativistic Heavy Ion Collider (RHIC). Transverse single-spin asymmetry measurements for particles produced in proton-proton collisions provide insight into initial and final state spin-momentum and...
We revisit inclusive $J/\psi$ and $\Upsilon$ photoproduction at lepton-hadron colliders, namely in the limit when the exchanged photon is quasi real. Our computation includes the next-to-leading-order (NLO) $\alpha_s$ corrections to the leading-order contributions in $v^2$.
We consider first large-$P_T$ inclusive photoproduction of $J/\psi$ at HERA and provide NLO predictions for the EIC...
The LHeC and the FCC-he are the cleanest, high resolution microscopes that the world can build in the nearer future. Through a combination of neutral and charged currents and heavy quark tagging, they will unfold the parton structure of the proton with full flavour decomposition and unprecedented precision. In this talk we will present the most recent studies on the determination of proton...
Almost all PDF fits so far take into account experimental uncertainties but not the uncertainties on theoretical predictions. Because theoretical predictions are typically computed at finite order in perturbation theory, they suffer from (often sizeable) uncertainties due to the missing higher orders. In a recent NNPDF study, theory uncertainties evaluated using scale variation have been...
The transversity distribution, $h^q_1(x)$, describes transversely polarized quarks inside a transversely polarized nucleon. As $h^q_1(x)$ is chiral-odd, it can only be accessed via a process where it couples to another chiral-odd function, such as the spin-dependent interference fragmentation function (IFF), in $p^\uparrow p$ collisions. The coupling of $h^q_1(x)$ and IFF yields an...
Gluon nuclear Parton distribution functions (nPDFs) have been the subject of many studies over the past years, since they are important for many processes and difficult to constrain. Recently, nCTEQ15 nPDFs have been updated with vector boson and single inclusive hadron production data to address this issue. To constrain the gluon nPDF further, particularly towards $x$ values smaller than...
Many astrophysical observations as well as anomalies in processes involving electromagnetic currents (e.g. the muon anomalous magnetic moment) could be reconciled assuming the existence of a new kind of matter, not directly interacting with light, called Dark Matter (DM). While
gravitational effects of DM are quite well established, despite the tremendous efforts being devoted to reveal the...
We investigate the Feynman-$x$ spectra of the neutrons produced in the very forward direction in $ep$ collisions using the impact-parameter dependent color dipole model with and without saturation. Our analysis demonstrates that the W and $Q^2$ dependence of the cross-section are independent of the presence of a forward neutron, as predicted by Feynman-scaling. The models prediction are...
FASER$\nu$ is designed to directly detect collider neutrinos of all three flavors for the first time and provide new measurements of their cross-sections at energies higher than those detected from any previous artificial sources. In the pilot run data during LHC Run 2 in 2018, we observed the first neutrino interaction candidates at the LHC, opening a new avenue for studying neutrinos from...
While it has been known since the 60s that nucleons are composed of quarks and gluons, very little is understood about the mechanisms responsible for the emergence of nucleons from these partons. Generalized Parton Distributions (GPDs) provide the opportunity to obtain a 3-dimensional, tomographic picture of a nucleon. Moreover, GPDs are related to total angular momentum, mass and pressure...
The associated production of a vector bosons and jets constitutes an excellent environment to perform experimental tests of perturbative QCD. Inclusive and differential cross sections of vector bosons produced in association with jets at 13 TeV will be presented for various physics channels. Differential distributions as function of a broad range of kinematical observables are measured and...
New measurements of impact parameter dependence of photon-photon interactions in ultraperipheral PbPb collisions (UPC) are presented, using data collected by the CMS detector during the LHC Run 2. The “UPC centrality” is classified based on the number of neutrons (including 0, 1, or at least two) detected in the very forward pseudorapidity to control the impact parameter of UPCs. The...
One of the primary goals of the proposed future collider experiments is to search for dark matter (DM) particles using different experimental approaches. High energy e$^+$e$^-$ colliders offer unique possibility for the most general search based on the mono-photon signature. As any e$^+$e$^-$ scattering process can be accompanied by a hard photon emission from the initial state radiation,...
Generalized Parton Distributions are studied in exclusive reactions
like Deeply Virtual Compton Scattering (DVCS). In 2016 and 2017
DVCS was measured at COMPASS using 160 GeV positively and negatively
charged polarized muon beams provided by the M2 beamline of the SPS at CERN and
which was scattered off a 2.5 m long liquid hydrogen target. To perform an
exclusive measurement the...
The NA62 experiment at CERN took data in 2016-2018 with the main goal of measuring the K+ -> pi+ nu nubar decay.
A large sample of charged kaon decays into final states with multiple charged particles has been collected in 2016-2018 by the NA62 experiment at CERN. This sample provides sensitivities to lepton flavour/number violating decays of the charged kaon and of the neutral pion with...
Measurements of W/Z-boson production in association with jets are an important test of perturbative QCD prediction and also yield information about the parton distribution functions of the proton. This talk will present recent Z+jets results focusing on extreme phase-spaces with high pT jets as well as high pT heavy-flavour jets. The data are presented differentially and compared to...
We present a systematical study on proton-PDF uncertainties in the extraction of nuclear PDFs from W$^\pm$ production data in proton-lead collisions, using the theoretical covariance matrix and Hessian PDF reweighting methods to quantify the impact. We then discuss different ways to mitigate these theoretical uncertainties, including self-normalization, forward-to-backward and nuclear...
Ultra-peripheral collisions (UPC) of relativistic heavy-ion beams lead to a diverse set of photon-nucleus interactions. This talk presents two recent ATLAS measurements of photo-nuclear processes in Pb+Pb collisions at 5.02 TeV. The first measurement is that of photon-induced dijet production in UPC events. The clean environment of these events allows for precision measurements in a...
The LHeC and the FCC-he offer fascinating, unique possibilities for measurement of top properties and discovering BSM physics in DIS, both due to their large centre-of-mass energies and high luminosities. In this talk we will review the most recent studies. We will revisit the determination of the top mass through inclusive measurements. In addition, we will address the possibilities for...
The NA62 experiment at CERN took data in 2016--2018 with the main goal of measuring the K+ -> pi+ nu nubar decay. The high-intensity fixed-target setup and the detector performance make the NA62 experiment particularly suited to investigate the Standard Model structure and its possible extensions with precision measurements of charged kaon decays.
Results from studies of the radiative kaon...
Nuclear parton distribution functions (nPDFs) quantify the initial-state nuclear effects and provide a factorization-based input for perturbative calculations in nuclear collisions. These distributions can be determined in a global QCD analysis using wide range of experimental data. In addition to older fixed-target deep inelastic scattering and Drell-Yan dilepton production data, several...
Motivated by the research program of the Electron Ion Collider,
we have calculated the two-loop (NNLO) flavor-singlet (vector) coefficient
function of deeply virtual compton scattering (DVCS).
Apart from the result and some technical aspects of the calculation,
I will present numerical estimates of the size of the NNLO
correction to the corresponding Compton form factors.
The associated production of a vector bosons and jets coming from the hadronization of b, c quarks are a powerful experimental handle to study the heavy flavour aspects of pQCD. Several predictions including the effect of the heavy flavour mass can be tested and NLO precision can be achieved with physics comparisons to flavour schemes in generators. Inclusive and differential cross sections of...
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...
The decay K+→π+ νν ̅, with a very precisely predicted branching ratio of less than 10-10, is among the best processes to reveal indirect effects of new physics.
The NA62 experiment reports the branching ratio measurement BR(K+→π+νν¯) = (10.6+4.0−3.4|stat ± 0.9syst) × 10−11 at 68% CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data...
We present an updated determination of nuclear parton distributions (nPDFs) from a global NLO QCD analysis of hard processes in fixed-target lepton-nucleus and proton-nucleus together with collider proton-nucleus experiments. In addition to neutral- and charged-current deep-inelastic and Drell-Yan measurements on nuclear targets, we consider the information provided by the production of...
We study correlations originating from the quantum nature of gluons in a hadronic wave function. Bose-Einstein correlation between identical particles lead to the enhancement in the number of pairs of gluons with the same quantum numbers and small relative momentum. We show that these preexisting correlations can be probed in Deep Inelastic Scattering experiments at high energy. Specifically,...
I will discuss nonperturbative flavor correlations between pairs of leading and next-to-leading charged hadrons within jets at the Electron-Ion Collider (EIC). We introduce a charge correlation ratio observable $r_c$ that distinguishes same- and opposite-sign charged pairs. Using Monte Carlo simulations with different event generators, $r_c$ is examined as a function of various kinematic...
We discuss the use of machine learning techniques in effectively nonparametric modelling of generalised parton distributions (GPDs) in view of their future extraction from experimental data. Current parameterisations of GPDs suffer from model dependency that lessens their impact on phenomenology and brings unknown systematics to the estimation of quantities like Mellin moments. The new...
We present our theoretical results for the exclusive photoproduction of heavy quarkonia pairs in the kinematics of the future high-energy colliders, like the future Electron Ion Collider (EIC), the Large Hadron electron Collider (LHeC), and the Future Circular Collider (FCC-he). We found that in the leading order over the strong coupling $\alpha_s$ the produced quarkonia have opposite...
Preliminary results of the K± → µ ± π0π0ν (Kmu400) decay first observation and analysis based on the NA48/2 data collected in 2003-2004 are presented. The branching ratio measurement is done on the basis of 2437 selected candidates with about 20% background. In the restricted region of squared dilepton mass above 0.03 GeV^2/c^4, the branching ratio is Br(Kmu400, M2(2l)>0.03 GeV2/c4) = (0.65 ±...
We report the results of a new global QCD analysis which includes deep-inelastic $e/\mu$ scattering (DIS) data off proton and deuterium, as well as lepton pair production in Drell-Yan process in $pp$ and $pD$ collisions and $W^\pm/Z$ boson production data from $pp$ and $p \bar p$ collisions at LHC and Tevatron. We address nuclear corrections in DIS in terms of a nuclear convolution model with...
A momentum charge correlation ratio observable $r_{c}$, generalized from the balance function [1], is measured using data recorded with the H1 experiment at HERA during 2003 to 2007. This variable distinguishes between same-sign and opposite-sign charged particle pairs[2] in a jet. The average $r_{c}$ is studied for two configurations (prongs) of the leading particles in the jet, defined with...
SND@LHC is a compact and stand-alone experiment to perform measurements with neutrinos produced at the LHC in a hitherto unexplored pseudo-rapidity region of 7.2 < 𝜂 < 8.6, complementary to all the other experiments at the LHC. The experiment is to be located 480 m downstream of IP1 in the unused TI18 tunnel. The detector is composed of a hybrid system based on an 800 kg target mass of...
Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity $ep$ scattering at a centre-of-mass energy $\sqrt{s}=318$ GeV with the ZEUS detector at HERA. Two- and four-particle azimuthal correlations, as well as multiplicity, transverse momentum, and pseudorapidity distributions for charged-particle multiplicities $N_{\rm ch} \geq 20$ are...
We derive subeikonal corrections to the quark propagator assuming that the quark is propagating through the whole medium in order to study DIS dijet production. We take into account NEik (Next-to-Eikonal) corrections from previous results for splitting before the medium and we calculate a new contribution coming from splitting inside the medium at NEik. This time we include not only...
We construct a new parametrization of nuclear PDFs (nPDFs) inspired by short-range correlation (SRC) models, and implement this in a global fit. The SRC motivated parametrization decomposes the nPDFs into a free nucleon component, and a part describing the formation of the bound nucleon pairs. Here, the A-dependence enters only through multiplicative factors describing the number of the...
Vector boson scattering is a key production process to probe the electroweak symmetry breaking of the standard model, since it involves both self-couplings of vector bosons and coupling with the Higgs boson. If the Higgs mechanism is not the sole source of electroweak symmetry breaking, the scattering amplitude deviates from the standard model prediction at high scattering energy. Moreover,...
We apply the formalism developed earlier by Kovchegov, Pitonyak, and Sievert for constructing transverse momentum dependent parton distribution functions (TMDs) at small Bjorken-x to derive the small-x evolution equations for the Boer-Mulders TMD. We construct evolution equations which resum double logarithms $\alpha_s \textrm{ln}^2 (1/x)$, obtaining a closed set of equations in the large $N_c$ limit.
Positron beams play a crucial role in the experimental programs of the next generation of lepton accelerators. In the context of the hadron-physics program of Jefferson Lab (JLab), positron beams are complementary to electron beams in the quest for a precise understanding of the structure of nucleons. In particular, the deeply-virtual scattering of polarized and unpolarized electrons and...
Event shapes provide incisive probes of QCD, both its perturbative and non-perturbative aspects. Grooming techniques have been developed to separate perturbative from non-perturbative components of jets in a theoretically well-controlled way, and have been applied extensively to jet measurements in hadronic collisions. In this talk the first application of grooming techniques to event shape...
We perform the first global QCD analysis of pion valence, sea quark, and gluon distributions within a Bayesian Monte Carlo framework with threshold resummation on Drell-Yan cross sections at next-to-leading logarithmic accuracy. Exploring various treatments of resummation including in Mellin-Fourier and double Mellin space, we find that the behavior of the valence quark distribution at...
This talk reviews recent measurements of multiboson production using CMS data. Inclusive and differential cross sections are measured using several kinematic observables.
There has been significant discussion in the community regarding a future $\mu^+\mu^-$ collider. While such a facility is still decades away from realization, it is also understood that significant technological development and feasibility demonstrations are necessary at lower beam energies. Here we propose such a possibility coupled with a rich physics program. We propose a future Muon-Ion...
We perform the first simultaneous global QCD analysis of spin-averaged and spin-dependent parton distribution functions (PDFs), including single jet production data from unpolarized and polarized hadron collisions. We critically assess the impact of SU(3) flavor symmetry and PDF positivity assumptions on the quark and gluon helicity PDFs, and find strong bias from these, particularly on the...
Missing higher order uncertainties (MHOU) in perturbative computations are usually estimated by varying the unphysical scales present in the process. However, it is known that scale variation prescriptions often underestimate the actual uncertainty. In this talk, we present a more reliable approach to approximate the unknown next-to-next-to-leading order (NNLO) transverse momentum distribution...
Measurements of multiboson production at the LHC probe the electroweak gauge structure of the Standard Model for contributions from anomalous couplings. In this talk we present recent ATLAS results on the first observation of three W boson production at the LHC (WWW). If available, we also present the differential cross-section measurement of the Z boson produced in association with two...
We propose a novel approach to high energy scattering that allows to interpolate between the Bjorken limit and the Regge limit of QCD. It consists in performing a partial twist expansion of cross-sections which allows to resum to all orders higher twists that contribute to gluon saturation at small x. We discuss the case of gluon mediated DIS and DVCS as a first application. In this framework...
We discuss the measurement of gluon transverse momentum distribution (TMD) in dijet and heavy hadron pair (HHP) production in semi-inclusive deep inelastic scattering. The factorization of these processes in position space shows the appearance of a specific new soft factor matrix element on top of angular and complex valued anomalous dimensions. We show in detail how these features can be...
We compute the in-medium jet broadening $\langle p^2_\perp\rangle$ to leading order in energy in the opacity expansion. At leading order in $\alpha_s$ the elastic energy loss gives a jet broadening that grows with $\ln{E}$. The next-to-leading order in $\alpha_s$ result is a jet narrowing, due to destructive LPM interference effects, that grows with $\ln^2{E}$. We find that in the opacity...
The QCD strong coupling (alpha_s) and the parton distribution functions (PDFs) of the proton are fundamental ingredients for phenomenology at high-energy facilities such as the Large Hadron Collider (LHC).
It is therefore of crucial importance to estimate any theoretical uncertainties associated to them.
Both alpha_s and PDFs obey their own renormalisation-group equations (RGEs) whose...
We use small-$x$ helicity evolution equations to analyze the world polarized DIS and Semi-inclusive DIS (SIDIS) data. After successfully describing the $g_1$ structure function extracted from polarized DIS, we extend this analysis to the small-$x$ $g^h_1$ structure function measured in polarized SIDIS. The fit is performed through a Monte-Carlo analysis within the JAM global framework....
The scattering of electroweak bosons tests the gauge structure of the Standard Model and is sensitive to anomalous weak boson self interactions. In this talk, we present recent results on weak-boson scattering from the ATLAS experiment using proton-proton collisions at sqrt(s)=13 TeV. We present the first observation of Z+jets production, in two final states where the Z boson decays...
We investigate the impact of the Balitsky-Kovchegov (BK) non-linear corrections on the initial conditions and evolution of twist components of the DIS cross-section at small x. The twist decomposition of the BK-driven DIS cross-section is performed in the Mellin space. Three main contributions are found that may be interpreted in the OPE framework as: 1) a modification of the input for DGLAP...
The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment, with steel as absorber and plastic scintillators as active medium. The High-Luminosity phase of LHC, delivering five times the LHC nominal instantaneous luminosity, is expected to begin in 2029. TileCal will require new electronics to meet the requirements of a 1 MHz trigger,...
We will report on recent works featuring the parton distribution functions (DFs) of pion-like systems at experimental scales, following an approach based on the assumption that there is an effective charge which defines an evolution scheme for DFs that is all-orders exact. Within this framework, strict lower and upper bounds on all Mellin moments of the valence-quark DFs are derived....
We present a Monte Carlo generator for off-shell top-quark pair production and decay in the semileptonic channel. The generator takes form of an extension to a generator which implements $t\bar{t}$ production in the dileptonic channel in terms of the exact matrix elements for $pp\to \ell^+\nu_{\ell}\, l^-\bar{\nu}_{l}b\bar{b}$ at order $\alpha^4 \alpha_s^2$ plus full NLO QCD corrections. The...
We present a technique to reconstruct the scaling variables defining ep deep inelastic scattering based on a kinematic fit. Most techniques in use rely only on two of the four available quantities(energy and angle of the electron and struck quark), while the kinematic fit uses all available information simultaneously. Initial state radiation is included in the framework. The fitting is...
I will discuss the application of Soft Collinear Effective Theory (SCET) to the extraction of the strong coupling constant from e+e- event shape distributions, where state-of-the-art results exhibit a few sigma discrepancy with respect to the PDG world average. After briefly introducing event shape distributions and the SCET resummation formalism we use to study them, I will then focus on the...
The virtual photon asymmetry $A_1$ is one of the fundamental quantities that provide information on the spin structure of the nucleon. The value of $A_1$ at high $x_{Bj}$ is of particular interest because valence quarks dominate in this region, which makes it a relatively clean region to study the nucleon structure. Several theoretical calculations, including naive SU(6) quark model,...
When parton momentum faction $x$ of hadron becomes small, an enhancement from small-$x$ logarithms shows up, and eventually, we enter into a partonic saturation region. A consistent treatment of the small-$x$ logarithms requires an all-order resummation which can be achieved with the BFKL formalism. However, a boundary to delineate the small-$x$ resummation region from saturation one is...
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is an upgrade of the B factory facility at KEK in Tsukuba, Japan. The experiment began operation in 2019 and aims to record a factor of 50 times more data than its predecessor. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First...
Low-energy nuclear structure physics continues to be a vibrant field of research, as ever more capable rare isotope facilities look for new elements further away from stability. At these dedicated facilities, short-lived nuclei decay in flight between the production and detection points, making those with shorter decay times difficult to study. The future EIC, however, will have heavy ion...
The study of the spin structure of the nucleon by measuring nucleon spin (in)dependent azimuthal asymmetries in Drell-Yan process is one of the main topics of the phase-II research programme of the COMPASS experiment (M2 beamline, SPS, CERN).
In 2015 and 2018 COMPASS performed Drell-Yan measurements using a 190 GeV $\pi^-$ beam interacting with a transversely polarized $NH_3$ and unpolarized...
Ultraperipheral lead-lead collisions at $\sqrt{s_{_{\mathrm{NN}}}} = 5.02$ TeV produce very large photon fluxes that provide the conditions to study photon-photon fusion processes in phase space regions inaccessible with proton-proton data. Measurements of light-by-light ( LbL) scattering and e+e- (Breit-Wheeler) production in ultraperipheral PbPb collisions with data collected during the 2015...
Transverse-momentum-dependent parton distribution functions (TMD PDFs) are essential for describing elementary high-energy processes involving the hadron, such as semi-inclusive deep-inelastic scattering (SIDIS). Basis Light-Front Quantization (BLFQ) now provides the hadron's light-front wave functions in the leading Fock sector of three valence quarks. We report the first calculations within...
In this talk we discuss the impact of the physics programme at the LHeC and FCC-he on the respective $hh$ ones, the HL-LHC and the FCC-hh, and the synergies between both collision modes. We address precision SM measurements, Higgs physics, high-mass searches, parton densities, small-$x$ physics and heavy ion physics with $e$A input, extending the discussions in the 2020 LHeC Conceptual Design...
We investigate the two-photon transitions $H_{c\bar c} \to \gamma^*\gamma$ of the charmonium system in light-front dynamics. The light-front wave functions were obtained from solving the effective Hamiltonian based on light-front holography and one-gluon exchange interaction within the basis light-front quantization approach. We compute the two-photon transition form factors as well as the...
The upcoming Electron Ion Collider (EIC) at Brookhaven National Lab will provide novel opportunities to study the structure of light nuclei. Exclusive reactions in particular, such as Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP), have clean final states which allow us to effectively extract Generalised Parton Distribution (GPDs). This makes them important...
Ultraperipheral lead-lead collisions at $\sqrt{s_{_{\mathrm{NN}}}} = 5.02$ TeV produce very large photon fluxes that fundamental quantum-mechanical processes can be observed. In this presentation, the first observation of the $\tau$ lepton production in ultraperipheral PbPb collision data collected by CMS at LHC is reported. This measurement paves the way for the determination of the anomalous...
Higgs production cross sections at LHeC (FCC-he) energies are as large (larger than) those at future $Z-H$ $e^+e^-$ colliders. This provides alternative and complementary ways to obtain very precise measurements of the Higgs couplings, primarily from luminous, charged current DIS. Recent results for LHeC and FCC-he are shown and their combination is presented with $pp$ (HL-LHC) cross...
Quarkonium production is modified in ultra-relativistic heavy-ion collisions with respect to p+p collisions due to color-screening and recombination of heavy quark pairs inside the hot QCD medium, known as the quark-gluon plasma (QGP). Such modifications, referred to as hot nuclear matter effects, depend on the size and temperature of the QGP, the binding energy and formation time of the...
Angular correlations present in dijet photoproduction are studied, for the first time, using ultraperipheral lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The second moment of the angular distribution, $\langle \cos(2\Phi) \rangle$, where $\Phi$ is the angle between the vector sum $\vec{Q}_\mathrm{T}$ and the vector difference $\vec{P}_\mathrm{T}$ of the...
Transverse momentum dependent (TMD) distributions match collinear parton density functions (PDF) in the limit of small transverse distances, which is accounted for by global extractions of TMD distributions. We study the influence of the PDF choice on the determination of unpolarized TMDPDFs and the description of TMD Drell-Yan-pair and Z-boson production data. We find that PDF essentially...
Relativistic heavy-ion beams at the LHC are accompanied by a large flux of equivalent photons, leading to multiple photon-induced processes. This talk presents a series of measurements of such processes performed by the ATLAS Collaboration. New measurements of exclusive dilepton production (electron, muon, and tau pairs) are discussed. These processes provide strong constraints on the nuclear...
AMBER (Apparatus for Meson and Baryon Experimental Research) is a new experiment located on the M2 beam line of CERN SPS. The understanding of the origin of the visible mass in the universe is one of its physics goals. It is known that the Higgs boson mechanism alone is not sufficient to explain the mass of a nucleon. Another phenomenon must interplay with it to explain the emergence of the...
One of the golden measurements at the Electron-Ion Collider (EIC) is to measure the coherent diffractive Vector Meson (VM) production off heavy nucleus. The measurement is expected to be sensitive to the non-linear gluon dynamics - saturation, and most importantly, it also provides the gluon density distribution of the nucleus. While the measurement was established in the EIC White Paper 10...
Factorization theorems are known to be extremely powerful tools in high-energy particle physics. Processes like SIDIS, Drell-Yan vector-boson production, Higgs-boson production through gluon fusion and $e^+e^-$ to jets and/or hadrons are just some examples of processes that have been thoroughly investigated by applying rigorous factorization formulae. Furthermore, if in these processes the...
Parton branching solutions of QCD evolution equations have recently been studied
to construct both collinear and transverse momentum dependent (TMD) Parton
distributions. In this formalism, soft-gluon colour coherence effects are taken into account by
introducing the soft-gluon resolution scale. In this talk, we show results of fits to the high precision deep inelastic scattering (DIS)...
$J/\psi$ production has been studied extensively in high energy $p+p$ and heavy ion collisions at RHIC and other facilities in the world, and several promising pQCD based production models have been investigated in details, however, our understanding of the production mechanisms still remain largely uncertain. The recent observations of enhanced particle yields, including $J/\psi$, in high...
We consider the exclusive photo-production of a gamma-meson pair, working in the QCD factorisation framework. Explicitly, we consider a rho meson and a charged pion in the final state. This process has a significant advantage over meson production, since it allows us to probe chiral-odd GPDs, which are not well-known experimentally. The computation is performed at leading order and leading...
With transverse-momentum-dependent parton densities (TMD) obtained from fits to HERA DIS data using the Parton Branching (PB) method, we determine the non-perturbative Collins-Soper (CS) kernel. The CS kernel describes the rapidity evolution of quark TMD parton distribution functions. We use PB-TMD calculations of the Drell-Yan (DY) transverse momentum spectrum at different DY masses. We show...
Building upon the most recent CT18 global fit, we present a new set of parton distribution functions including the photon content of the proton based on an application of the LUX formalism. In this work, we explore two principal variations of the LUX ansatz. In one approach, which we designate "CT18lux," the photon PDF is calculated directly using the LUX formula for all scales, $\mu$. In an...
Understanding the spin of the proton is one of the fundamental questions in QCD, which is also one of central pillars of the Electron-Ion-Collider (EIC) physics program. The existing data from fixed-target polarized lepton-nucleon DIS experiments and polarized proton-proton experiments, provided us with good knowledge on the quark spin contribution $\Delta \Sigma$ and gluon spin contribution...
Heavy flavour production measurements in hadron collisions serve as testing ground of perturbative QCD (pQCD) calculations. Quarkonia, bound states of heavy quark-antiquark pairs, are unique tools to test both perturbative and non-perturbative aspects of QCD. In particular, the heavy-quark pair production process is described by pQCD while the formation of the bound state is non-perturbative....
Coherent deep virtual exclusive scattering (DVES) is an important tool for mapping the quark- and gluon-matter densities of nuclei. The separation of quark and gluon contributions can be achieved by combining the $e\,{}^{Z}\!\text{A} \to e\,{}^{Z}\!\text{A}\gamma$ (DVCS), $e\,{}^{Z}\!\text{A}\to e\,{}^{Z}\!\text{A} \phi$ and $e\,{}^{Z}\!\text{A}\to e\,{}^{Z}\!\text{A}J/\Psi$ reactions. This...
STAR’s recent observations of the Breit-Wheeler process and vacuum birefringence have demonstrated that ultra-peripheral heavy-ion collisions provide an abundant source of linearly polarized photons. We utilize such polarized photons in diffractive photo-nuclear vector meson production ($\rho^0 \rightarrow \pi^+ \pi^-$) to observe a novel quantum interference effect between non-identical...
In this talk we present the potential of $\eta_{b,c}$ production from hadronic collisions to access the gluon TMD PDFs. In particular, we explore the phenomenology of the unpolarized and linearly polarized gluon TMD PDF in unpolarized collisions for different kinematic settings, and the potential of a fixed-target experiment at the LHC to access T-odd distributions such as the gluon Sivers TMD PDF.
We present the MSHT20qed set of parton distribution functions (PDFs). These are obtained from the MSHT20 global analysis via a refit including QED corrections to the DGLAP evolution at ${\cal O}(\alpha),{\cal O}(\alpha\alpha_S)$ and ${\cal O}(\alpha^2)$, and containing the photon PDF of the proton. As in the previous MMHT15qed study we use an input distribution for the photon that is derived...
Measurements of quarkonia production in peripheral and ultra-peripheral heavy-ion collisions are sensitive to photon-photon and photon-nucleus interactions, the partonic structure of nuclei, and to the mechanisms of vector-meson production. LHCb has studied both coherent and incoherent production of $J/\psi$ mesons in peripheral and ultra-peripheral collisions using PbPb data at forward...
In the parton branching (PB) approach, collinear and TMD parton densities have been determined by fits to inclusive deep inelastic scattering (DIS) HERA data. This method allows one to simultaneously take into account soft-gluon emission and the transverse momentum recoils in the parton branchings along the QCD cascade. The latter leads to a natural determination of the TMD PDFs in a proton. A...
Studies of open-charm hadron production in a partonic rich environment are performed at the LHC to investigate charm-quark hadronization mechanisms. Recent measurements of different charm meson (${\rm D^0}$, ${\rm D^+}$, ${\rm D^+_{\rm s}}$, ${\rm D^{*+}}$) and baryon ($\Lambda^+_{\rm c}$, $\Xi^{0,+}_{\rm c}$, $\Sigma^{0,++}_{\rm c}$, $\Omega^0_{\rm c}$) production in pp collisions at...
The exclusive photoproduction reactions $\gamma p \to J/\psi(1S) p$ and $\gamma p \to \psi(2S) p$ have been studied at an $ep$ centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 373 pb$^{-1}$. The measurement has been made in the kinematic range $30 < W < 180$ GeV, $Q^2 < 1$ GeV$^2$, $|t| < 1$ GeV$^2$, where $W$ is the photon--proton...
In this talk we will present a new calculation of $W^+ W^-$ production in the semi--exclusive channel, that is either with intact outgoing protons or rapidity gaps present in the final state, and with no colour flow between the colliding protons. This study provides the first complete prediction of the $W^+ W^-$ semi--exclusive cross section, as well as the breakdown between elastic and...
With the detector instrumented in the forward region, the collected Z boson events in the LHCb acceptance can be used to probe the proton structure. In this talk, the latest Z boson related measurements will be presented: the Z boson production cross-section measurement at 13 TeV, the Z boson angular coefficients measurement, and the measurement of Z+ c jet events for probing intrinsic charm....
The STAR Collaboration has been building a Forward Upgrade to supplement the excellent mid-rapidity capabilities of the STAR Detector for the final years of the RHIC program. The Forward Upgrade utilizes tracking and electromagnetic and hadronic calorimetry to trigger on and measure charged and neutral hadrons, photons, jets, and di-electrons over the pseudorapidity region 2.5 < η < 4. The...
We present fits to determine parton distribution functions (PDFs) using a diverse set of measurements from the ATLAS experiment at the LHC, including inclusive W and Z boson production, ttbar production, W+jets and Z+jets production, inclusive jet production and direct photon production. These ATLAS measurements are used in combination with deep-inelastic scattering data from HERA. Particular...
Exclusive and diffractive final states will provide a wealth of physics at the future Electron-Ion Collider (EIC). However, measurement of these final states provide a unique challenge for detector design since many of the final-state particles wind up at very large pseudorapidities ($\eta$ > 4.5), which is far beyond the acceptance of the central detector. These so-called “far-forward”...
We present a phenomenological study for the production of the charm quark
in the forward and far forward region. We discuss theory predictions for differential cross sections at NLO in QCD obtained with the S-ACOT-MPS General Mass Variable Flavor Number (GMVFN) scheme applied to pp collisions.
We show the impact of charm-quark fragmentation contributions on the theory prediction and we...
The exclusive photoproduction of vector mesons provides a unique opportunity to constrain the gluon distribution function within protons and nuclei. Measuring vector mesons of various masses over a wide range of rapidity and as a function of transverse momentum provides important information on the evolution of the gluon distribution within nuclei. A variety of measurements, including the...
By considering double spin asymmetry (DSA) in exclusive dijet production in $ep$ collisions, we demonstrate for the first time that the $cos(\phi)$ angular correlation between the scattered electron and proton is a direct probe of the gluon orbital angular momentum and its interplay with the gluon helicity. We also make an estimate of the DSA for typical kinematics of the future Electron Ion Collider.
This talk reviews the most recent results in the study of standard model physics data analysis with the data collected by the CMS Collaboration.
FoCAL is a high-granularity forward calorimeter to be installed as an ALICE upgrade subsystem during the LHC Long Shutdown 3 and take data during the LHC Run 4. It consists of a compact silicon-tungsten sampling electromagnetic calorimeter (FoCAL-E) with pad and pixel readout layers to achieve high spatial resolution
for discriminating between isolated photons and decay photon pairs, and a...
I will discuss the extension of the nucleon spin sum rule to QCD×QED. I will present the QED corrections to the evolution of the quark and gluon helicity and orbital-angular-momentum (OAM) distributions, which are calculated for the first time, and discuss the necessary inclusion of photon and lepton helicity and OAM distributions.
The proposed forward physics facility at the LHC will offer the opportunity to collect a large data set of neutrino deep inelastic scattering in the energy range of $\sim 100-1000$ GeV. Already with Run 3, the FASER$\nu$ and SND@LHC experiments will collect neutrino events in the forward region 480 m from the ATLAS interaction point. The high energy electron neutrino and tau neutrino fluxes...
The CMS measurements of double-differential inclusive jet cross sections of and triple-differential top quark-antiquark pair production cross sections at the center of mass energy of 13 TeV are used together with the data of inclusive deep inelastic scattering to extract the parton distribution functions in the proton, the top quark mass and the strong coupling constant. Using standard model...
Heavy ions accelerated at ultra-relativistic energies generate a strong electromagnetic field, leading to photon-photon and photonuclear interactions during the collision. The photoproduction of the J/$\psi$ vector meson has been widely studied in ultra-peripheral collisions with an impact parameter larger than twice the ion radius, where hadroproduction is negligible. In the last few years,...
The LHCb experiment covers the forward region of proton-proton collisions, and it can improve the current electroweak landscape by studying the production of electroweak bosons in this phase space complementary to ATLAS and CMS. In this talk, an overview of the wide LHCb electroweak measurement program will be presented. This includes the recent measurement of the W boson mass.
Measurements of the production of hadrons containing beauty quarks
in pp and p--Pb collisions provide an important test of quantum chromodynamics calculations as well as the possibility to investigate fragmentation mechanims and modifications of the PDF in nuclei.
The use of machine-learning techniques for multi-class classification, coupled with the excellent particle identification,...
The Forward Physics Facility (FPF) is a proposal to create a cavern with the space and infrastructure to support a suite of far-forward experiments at the HL-LHC. The FPF would make possible a wide range of QCD studies, from proton structure at extremely low-x values to testing BFKL dynamics and modelling hadron and charm production as required by high-energy astrophysics experiments....
We present a new study on helicity amplitudes and cross sections for the exclusive production of $\rho$ mesons at the EIC in high-energy factorization. In this framework the analytic expression of amplitudes takes the form of a convolution between an off-shell impact factor depicting the $\gamma^* \to \rho$ transition and a nonperturbative density, known as Unintegrated Gluon Distribution...
Incompleteness in current knowledge of neutrino interactions with nuclear matter imposes a primary limitation in searches for leptonic CP violation carried out at long-baseline neutrino experiments like DUNE. In this talk, we summarize a recent computation that elevates the theoretical accuracy to next-to-next-to-leading order in QCD for charged-current DIS processes relevant for ongoing and...
A first measurement of the 1-jettiness event shape observable in neutral-current deep-inelastic electron-proton scattering is presented. The 1-jettiness observable $\tau_{1b}$ is defined such that it is equivalent to the thrust observable defined in the Breit frame. The data were taken in the years 2003 to 2007 with the H1 detector at the HERA ep collider at a center-of-mass energy of 319 GeV...
We investigate the relation between the topology of a nucleon and its spin composition. We approach this question in 1+1 dimensional single-flavor QCD with a large number of color. In this limit the theory can be shown to be dual to the exactly solvable sine-Gordon model. The spectrum of baryons and mesons is known analytically, and the baryon is a topological kink of the sine-Gordon model....
Recent results from the proton-proton collision data taken by the ATLAS experiment on B_c production and decays will be presented. The measurement of the differential ratios of the B_c+ and B+ production cross sections at 8 TeV will be shown. New results on the B_c decays to J/psi Ds(*) final states obtained with the Run 2 data at 13 TeV will also be reported.
Coherent exclusive $J/\psi$ photoproduction in heavy-ion ultraperipheral collisions (UPCs) at the LHC, Pb+Pb $\rightarrow$ Pb+$J/\psi$+Pb, has traditionally been suggested as an efficient probe of the gluon distributions. We show, by approximating the GPDs involved in this process with collinear PDFs, that this is indeed the case in the leading order pQCD but at NLO the situation changes...
We describe the status of the ATLAS Forward Proton Detectors (AFP and ALFA) for LHC Run 3 after all refurbishments and improvements done during Long Shutdown 2. Based on analysis of Run 2 data, the expected performance of the Tracking and Time-of-Flight Detectors, the electronics, the trigger, and the readout and detector control and data quality monitoring are described. Finally, the physics...
Seven years after the preliminary data were made available, the CLAS collaboration published both CLAS and CLAS12 results on the beam-spin asymmetry in semi-inclusive dihadron production off proton target. We present the phenomenological extraction of the associated twist-3 collinear PDF, e(x), made possible through the analysis of dihadron fragmentation function. We will discuss the extent to...
The EMC effect -- the modification of quarks in bound nucleons -- is a decades-old open question in QCD research, with far-reaching implications for our understanding of the fundamental structure of matter. While inclusive deep inelastic scattering (DIS) measurements have characterized many features of the EMC effect, their insensitivity to the initial state of the struck bound nucleon limits...
We provide state-of-the art SCETlib predictions for the $W$ and $Z/\gamma^*$ transverse-momentum ($q_T$) distributions at the LHC at complete three-loop order in resummed perturbation theory (N$^3$LL$'$) and matched to available fixed order. We compare our predictions to high-precision measurements by the ATLAS and CMS experiments. We pay particular attention to the estimation of theory...
Generalized Parton Distribution (GPDs) are universal functions which provide a comprehensive description of hadron properties in terms of quarks and gluons. Deeply Virtual Compton Scattering (DVCS) is the simplest process involving GPDs. In this talk, we will present the latest $ep \to e p \gamma$ cross sections obtained from Jlab Hall A data at three values of the Bjorken variable $x_B$. In...
The transverse momentum transfer dependence of differential cross sections for coherent photoproduction of heavy quarkonia on nuclei is studied in the framework of the color dipole model.
In our calculations, the higher-twist nuclear shadowing related to the $\bar QQ$ Fock component of the photon includes the correlation between dipole orientation $\vec r$ and impact parameter of a...
The most recent results on top quark physics, obtained using data collected with the CMS experiment at 5.02 and 13 TeV center-of-mass energies, are presented.
SeaQuest has measured dimuon events from the interaction of 120 GeV proton beam on liquid hydrogen and deuterium targets with dimuon mass between 2 and 8 GeV. These dimuon events contain both the Drell-Yan process and the charmonium ($J/\psi$ and $\psi^\prime$) production. Unlike the Drell-Yan process which probes the antiquark distributions in the nucleons, the charmonium production is...
Exclusive vector meson production is a powerful process to probe the small Bjorken-$x$ structure of protons and nuclei, as such processes are especially sensitive to gluonic structure and also provide access to the spatial distribution of small-$x$ gluons in nuclei. A powerful theoretical framework to study vector meson production at high energy, and to describe the initial condition of heavy...
The cross section for inclusive jet production in high-energy $pp$ collisions is well described by pQCD in the collinear factorization framework, which, together with its high rate and clear signal, makes it a key observable to study the proton structure. For $pp$ collisions at RHIC at a center-of-mass energy of $\sqrt{s} = 200~\text{GeV}$, the STAR detector provides jet measurements at $0.07...
After 9 years of successful operation in proton-proton collisions reaching up to $\sqrt{s}$ = 13 TeV, the ATLAS detector started in 2018 the preparations for an ambitious physics project, aiming the exploration of very rare processes and extreme phase spaces, an endeavor that will require a substantial increase in the integrated luminosity. To accomplish this purpose, a comprehensive...
The Electron-Ion Collider (EIC), to be built at Brookhaven National Lab within this decade, will provide high-precision access to the gluon and sea-quark dominated region of the nucleon. With luminosities of $10^{33-34}$ cm$^{-2}$s$^{-1}$, centre of mass energies 20-140 GeV, highly polarised electron and proton / light-ion beams and hermetic detectors, the collider will enable measurements of...
The large top quark samples in top quark pair and single top production have yielded measurements of the production cross section of unprecedented precision and in new kinematic regimes. They have also enabled new measurements of top quark properties that were previously inaccessible. In this contribution the highlights of the ATLAS top quark precision program are presented. ATLAS presents in...
Determining the multi dimensional structure of protons and nuclei at high energy is one central goal of the future Electron-Ion Collider. This fundamental information is a crucial input for models describing the initial state of heavy ion collisions. In particular the event-by-event fluctuating proton geometry should have a strong effect on the flow and multiplicity distribution in high...
While the unpolarized valence quark ($d$ and $u$) distributions are well determined from DIS experiments, their sea quark counterparts, $\bar{d}$ and $\bar{u}$, are much less constrained, in particular, near the valence region.
Measurements of $W^+/W^-$ production ratio in $pp$ collider experiments, such as the STAR experiment at RHIC, are sensitive to the $\bar{d}/\bar{u}$ ratio at leading...
DUNE is a next-generation long baseline experiment for neutrino science. An advanced Near Detector (ND) complex is foreseen for limiting the systematic uncertainties and ensure high precision measurements of neutrino oscillation parameters.
The SAND apparatus is one component of the ND permanently located on-axis with the primary goal of monitoring the beam and measure the neutrino flux....
The proton structure can be parameterized through Generalized Parton Distributions (GPDs) - a formalism that describes exclusive processes and allows to perform tomography of the nucleon. Measurements of exclusive processes, such as Deeply Virtual Compton Scattering (DVCS), are sensitive to complex integrals of GPDs, known as Compton Form Factors (CFFs). To gain access to the elusive CFF E for...
Run 2 of the LHC has witnessed the observation of many rare top quark production processes predicted by the Standard Model and has boosted searches for flavour-changing-neutral-current interactions of the top quark, that are heavily suppressed in the SM. In this contribution highlights of searches by the ATLAS experiment for rare processes involving top quarks are shown. Results are presented...
The Liquid Argon Calorimeters are employed by ATLAS for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic and forward calorimetry in the region from |η| = 1.5 to |η| = 4.9. It also provides inputs to the first level of the ATLAS trigger. After successful period of data taking during the LHC Run-2 between 2015 and 2018 the ATLAS detector entered into a...
We perform a global QCD analysis of unpolarized parton distributions within a Bayesian Monte Carlo framework, including the new $W$-lepton production data from the STAR Collaboration at RHIC and Drell-Yan di-muon data from the SeaQuest experiment at Fermilab. We assess the impact of these two new measurements on the light antiquark sea in the proton, and the $\bar{d}-\bar{u}$ asymmetry in...
The gluon radius of the proton is expected to increase at small gluon momentum fractions x, an effect which has hitherto not been considered in the dipole model framework. We investigate the energy dependence of exclusive J/ψ, φ, and ρ production by introducing three models for x dependence of the gluon thickness function. We allow the transverse width of the proton to increase as x decreases,...
Evidence for the production of top quarks in heavy ion collisions is reported in a data sample of lead-lead collisions recorded in 2018 by the CMS experiment at a nucleon-nucleon center-of-mass energy of $\sqrt{s_{_{\mathrm{NN}}}} = 5.02$ TeV, corresponding to an integrated luminosity of $1.7\pm0.1\,\mathrm{nb}^{-1}$. Top quark pair ($\mathrm{t\bar{t}}$) production is measured in events with...
We investigate photo-production of vector mesons $J/\Psi$ and $\Psi(2s)$ and their potential use for finding evidence for the presence of non-linear QCD evolution at the LHC and future collider projects. Our study is based both on unintegrated gluon densities, subject to BK (non-linear) and NLO BFKL (linear) QCD low x evolution, and the study of dipole models. While the energy dependence of...
We present a new approach to fitting the $e^+P$ and $e^-P$ high-$x$ data from the ZEUS experiment\footnote{H.~Abramowicz et al. (ZEUS Collaboration), Phys. Rev. D
89, 072007 (2014); I.~Abt et al. (ZEUS Collaboration), Phys.Rev.D 101 (2020) 11, 112009 } based on a full forward modeling from the input PDFs to the expected number of events in measurement bins. Systematic uncertainties are...
The proposed Electron-Ion Collider (EIC), to be built at Brookhaven National Laboratory, will enable an unparalleled exploration of how the observed properties of nucleons and nuclei emerge from the interactions of their constituent partons. This program will be made possible both by a state-of-the-art machine, capable of colliding polarized electrons with either polarized protons or...
Generalized distribution amplitudes (GDAs) are the s-t crossing quantities of generalized parton distributions (GPDs), which can be measured in the process of $\gamma^* + \gamma \rightarrow M_1+ M_2$. In 2016, the Belle Collaboration released the measurements of differential cross section for $\gamma^* + \gamma \rightarrow \pi+ \pi$, from which the pion GDAs were extracted by using the...
Single top quarks are mainly produced through a t-channel W boson exchange, $q + b \to q^\prime + t$, at the LHC. The computation of the last missing ingredient for NNLO QCD corrections, the non-factorisable two-loop amplitude, was recently completed.
Despite being colour-suppressed and hence previously neglected, there is reason to expect this correction to have an impact comparable to that...
The ATHENA (A Totally Hermetic Electron-Nucleus Apparatus) detector is designed to deliver the full physics program of the Electron-Ion Collider (EIC) as set out in the community EIC White Paper and the U.S. National Academy of Sciences report, providing the best possible acceptance, resolution, and particle identification capabilities. ATHENA has been designed to accommodate all necessary...
We present calculations of QCD corrections for the associated production of a single top quark and a photon ($tq\gamma$) in proton-proton collisions. We calculate the NLO cross section as well as the approximate NNLO (aNNLO) cross section with soft-gluon corrections, including theoretical uncertainties, at collider energies of up to 100 TeV. We show results with various choices of parton...
We present a novel method to reconstruct the kinematics of neutral-current deep inelastic scattering (DIS) using a deep neural network (DNN). Unlike traditional methods, it exploits the full kinematic information of both the scattered electron and the hadronic-final state, and it accounts for QED radiation by identifying events with radiated photons and event-level momentum imbalance. The...
I will discuss recent work on the issues that arise when dealing with ultraviolet renormalization of both collinear and TMD Parton densities. In particulars, I will discuss how some commonly assumed properties like positivity can be violated in standard schemes. I will discuss the ways that using TMD parton densities can help even when dealing with collinear pdfs.
With a unique geometry covering the forward rapidity region, the LHCb detector provides unprecedented kinematic coverage at low Bjorken-$x$ down to $x \sim 10^{-5}$ or lower. The excellent momentum resolution, vertex reconstruction and particle identification allow precision measurements down to very low hadron transverse momentum. In this contribution we present the latest studies of the...
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$80%) electrons in...
The STAR collaboration has recently reported on the observation of a significant suppression of forward back-to-back hadron pairs produced in p-Au and p-Al collisions compared to p-p collisions [1]. The A-dependence of this suppression follows the expectations of the color glass condensate effective theory of high-energy QCD, thus giving evidence of the manifestation of gluon saturation at...
We present EKO, a new PDF evolution code, and yadism, a new DIS structure function library. Both programs produce operators which are independent from the boundary condition, can be stored and quickly applied to several PDFs.As a first application we show a determination of intrinsic charm content of the proton. Both codes are fully open source and written in Python, with a modular structure...
I present theoretical results for top-antitop pair production cross sections at current and future collider energies up to 100 TeV. I discuss the contribution of higher-order terms in the perturbative series. I show the very high quality of the soft gluon approximation through NNLO and the effect of contributions at aN$^3$LO.
For the SoLID Collaboration
SoLID (Solenoidal Large Intensity Device) is a large acceptance, high luminosity device proposed for fully exploiting the potential of the Jefferson Lab (JLab) 12 GeV energy upgrade. The scientific program of SoLID includes one parity-violating deep inelastic scattering (PVDIS) experiment, three semi-inclusive deep inelastic scattering experiments, and one...
The broadening of the away side peak of the photon-hadron cross section has been predicted to be a sensitive probe of non-linear gluon dynamics in high energy pp and especially pA collisions. In this contribution I plan to show explicit results [1] based on our extensive numerical computation of the photon-hadron cross section that has been recently measured by PHENIX [2] at 200 and 510 GeV in...
In this talk, the xFitter project is presented. xFitter is an open-source package that provides a framework for the determination of the parton distribution and fragmentation functions for many different kinds of analyses in Quantum Chromodynamics (QCD). xFitter version 2.2.0 has recently been released and offers an expanded set of tools and options. xFitter has been used for a number of...
I discuss C-conjugation odd color charge correlations in the
light-front wave function of the proton at moderately small $x$,
and for perturbative momenta.
The proton is approximated by an effective three-quark Fock
state to which we add the one-gluon emission correction in
light-cone perturbation theory.
The observed non-trivial dependence of the correlations on
impact parameter and on...
We discuss the impact of top-quark pair production differential cross section measurements from CMS and ATLAS at center of mass energy of 13 TeV on the CT18 proton PDFs. We discuss various phenomenological aspects of novel QCD analyses obtained with this extended baseline of data sets and in particular the impact on the gluon PDF.
The Precision Proton Spectrometer (PPS) is a new subdetector of CMS introduced for the LHC Run 2, which provides a powerful tool for advancement of BSM searches. The talk will present the new results on exclusive diphoton, ttbar, Z+X, and diboson production explored with with PPS, illustrating the unique sensitivity which can be achieved using proton tagging.
Fast interpolation-grid frameworks facilitate an efficient and flexible evaluation of higher-order predictions for any choice of parton distribution functions (PDFs) or value of the strong coupling constant $\alpha_s$. They constitute an essential tool for the extraction of PDFs and Standard Model parameters as well as studies of the dependence on the renormalization and factorization scales....
The matrix elements of the energy momentum tensor (EMT) between plane wave states define gravitational form factors (GFFs) which provide information about spatial distribution of energy, momentum and angular momentum. The Druck gravitational form factor is related to the mechanical stability of the nucleon and gives information about the spatial distributions of the forces inside the hadron....
Heavy meson production in reactions with nuclei is a new frontier to understand QCD dynamics and hadronization in nuclear matter. Measurements in various colliding systems, including Pb-Pb, Xe-Xe, O-O, p-Pb, and p-O at the LHC and the upcoming sPHENIX experiment, enable precision tests of the medium-size, temperature, and mass dependencies of the in-medium QCD evolution. We employ a coupled...
Many theories beyond the Standard Model (BSM) have been proposed to address several of the Standard Model shortcomings, such as the origin of dark matter and neutrino masses, the fine-tuning of the Higgs Boson mass, or the observed pattern of masses and mixing angles in the quark and lepton sectors. Many of these BSM extensions predict new particles or interactions directly accessible at the...
The Drell-Yan lepton pair productions have been measured to an unprecedented precision level at the LHC. In companion, the theoretical calculations should reach the same level. However, a visible discrepancy among different next-to-next-to-leading order (NNLO) calculations has been discovered by both the CTEQ-TEA group and also by S. Alekhin et al. In this study, we carefully examine the...
We present a new methodology that is able to yield a simultaneous deter- mination of the Parton Distribution Functions (PDFs) of the proton alongside any set of parameters that determine the theory predictions; whether within the Standard Model (SM) or beyond it. The SIMUnet methodology is based on an extension of the NNPDF4.0 neural network architecture, which allows the addition of an extra...
We present calculations of the invariant mass of the leading highest-p$_t$ jet in the production of Higgs/vector bosons in association with a single hard jet at hadron colliders. We pay particular attention to the structure of non-global logarithms both at fixed-order and to all-orders in QCD perturbative expansion. Our calculations are carried out in the eikonal (soft) approximation, and...
Extracting the non-perturbative transport coefficient $\hat q$ is an important approach to quantify the nuclear medium property probed by the jets traversing the medium. Electron-nucleus (eA) and proton-nucleus (pA) collisions provide a clean environment to delicately study the jet transport coefficient in cold nuclear matter and to test the theoretical framework of jet-medium interaction, and...
The structure of the proton has been studied by measuring the parton distribution function, which is the parton density distribution as a function of the longitudinal momentum of the parton, for long time. In the last few decades, the three-dimensional imaging of nucleon, such as the transverse momentum dependent parton distribution functions (TMDs), has received attention to better understand...
The realisation of the LHeC and the FCC-he at CERN require the development of the energy recovering technique in multipass mode and for large currents $\mathcal{O}(10)$ mA in the SRF cavities. For this purpose, a technology development facility, PERLE, is under design to be built at IJCLab Orsay, which has the key LHeC ERL parameters in terms of configuration, source, current, frequency and...
Thermal dark matter candidates are usually associated with the Weakly-interacting massive particles (WIMPS). However, vanilla WIMP scenarios suffer from severe experimental constraints. I would therefore like to discuss two alternatives to the standard picture: Inelastic Dark Matter and Dark Sectors with Bound States. In both cases, a dark matter candidate is in thermal contact with the...
In this talk we present initial accelerator considerations on a common IR to be built which alternately could serve $eh$ and $hh$ collisions at the HL-LHC, while other experiments would stay on $hh$ in either condition [1]. A forward-backward symmetrised option of the LHeC detector is sketched which would permit extending the LHeC physics programme to also include aspects of hadron-hadron and...
Quarkonium suppression is one of the more useful observables to obtain information about the hot medium created in ultrarelativistic heavy-ion collisions.
In this talk, we discuss a simple way to implement both the initial-state effects and the hot-medium evolution, and to compute the quarkonium nuclear modification factor if the survival probability for a bound state at a given energy...
Recently, the $Q^2$ dependence of several low moments of the proton longitudinal structure function, $F_L$, has been mapped thanks to the measurements taken at HERA and JLAB. In this contribution, we present the first lattice QCD determination of the lowest moment of $F_L$ and its $Q^2$ dependence. This is achieved by computing the forward Compton amplitude via an application of the...
Decays of B mesons that proceed through electroweak and radiative penguin amplitudes currently attract significant attention due to a number of observed discrepancies between the standard model predictions and the experimental results.
Belle II is expected to perform measurements on channels closely related to those exhibiting anomalies and that are uniquely available to Belle II. These...
There are new polarized structure functions, which do not exist for the spin-1/2 nucleons, in a spin-1 hadron such as the deuteron. In the near future, we expect that physics of spin-1 hadrons will become a popular topic, since there are experimental projects to investigate spin structure of the spin-1 deuteron at the Jefferson Laboratory, the Fermilab, the NICA, the LHCspin, and the...
My talk is baesed on our work of presenting the first complete next-to-leading-order (NLO) prediction for the single inclusive jet production in pA collisions at forward rapidities within the color glass condensate (CGC) effective theory. Our prediction is fully differential over the final state physical kinematics, which allows the implementation of the full jet clustering algorithm in our...
There have been rapid developments in direct lattice-QCD calculations of the Bjorken-x dependence of parton distributions. In this talk, I will highlight selected recent lattice-QCD results on parton distributions with emphasis on calculations at physical pion mass when applicable. Results include the continuum-physical isovector nucleon PDF, a first study of the strange and charm PDFs, the...
The search for lepton flavour violation is regarded as one of the main roads in the quest for new physics beyond the Standard Model. At PSI, Switzerland, the MEG II experiment will search for the $\mu \rightarrow e \gamma$ decay with the capability of setting an upper limit down to $6 \times 10^{-14}$, one order of magnitude below the result of the first-phase MEG experiment. The MEG II...
Polarization and spin-alignment measurements represent an important tool to understand the particle production mechanisms in proton-proton (pp) collisions. In heavy-ion collisions, quarkonium polarization could also be used to investigate the characteristics of a deconfined state of nuclear matter, the quark--gluon plasma (QGP), created at LHC energies. This measurement was performed for the...
Charm and bottom quark production is an important experimental observable that sheds light on the heavy quark interaction with the nuclear medium. With high statistics datasets, tracking and PID at very low transverse momentum, and excellent vertexing capabilities, LHCb performs precision measurements of a rich set of heavy flavor hadrons, including B mesons, open charm hadrons and charmonia....
The energy dependence of the total inclusive hadroproduction cross section of pseudo-scalar quarkonia and photoproduction cross section of vector quarkonia is computed via matching Next-to-Leading Order (NLO) Collinear-Factorisation (CF) results with resummed higher-order corrections, proportional to $\alpha_s^n ln^{n-1} (1/z)$, to the CF hard-scattering coefficient, where $z=M^2/\hat{s}$...
We re-interpret the jet clustering as an axis-finding procedure which, along with the proton beam, defines the virtual photon transverse momentum $q_T$ in deep inelastic scattering (DIS). In this way, we are able to probe the nucleon intrinsic structures with jets in a fully inclusive manner, similar to the Drell-Yan process. We present the factorization formulae and a complete list of the...
The light-cone definition of Parton Distribution Functions (PDFs) does not allow for a direct ab initio determination employing methods of Lattice QCD simulations that naturally take place in Euclidean spacetime. In this presentation we focus on pseudo-PDFs where the starting point is the equal time hadronic matrix element with the quark and anti-quark fields separated by a finite distance. We...
We introduce an effort to catalog the gauge-invariant interactions of Standard Model (SM) particles and new fields in a variety of representations of the SM color gauge group SU(3)c. In this first installment, we direct this effort toward fields in the six-dimensional (sextet, 6) representation. We consider effective operators of mass dimension up to seven (comprehensively up to dimension...
We present a calculation of the $\cos2\phi$ azimuthal asymmetry in $e ~p\rightarrow e ~J/\psi ~Jet~ X$, where $J/\psi-Jet$ pair is almost back-to-back in the transverse plane, within the framework of the generalized parton model (GPM) and assuming TMD factorization. This probes the Weisz{\"a}ker-Williams type linearly polarized gluon distribution. We calculate the asymmetry using...
Recent reduced pseudo Ioffe time distributions and matrix elements of current-current correlators generated from lattice QCD are used simultaneously with experimental data to extract pion parton distribution functions (PDFs) from a Monte Carlo global QCD analysis. Through the complementarity of the experimental and lattice QCD data, the analysis rigorously quantifies both the uncertainties of...
We present a novel study on the inclusive production of a heavy quarkonium (J/Ψ or Υ), in association with a light-flavored jet, as a test field of the high-energy QCD dynamics. The large transverse momenta at which the two final-state objects are detected permits to perform an analysis in the spirit of the variable-flavor number scheme (VFNS), in which the cross section for the...
Significant deviations from SM predictions have been observed in $ b \to s \mu^+ \mu^-$ decays and in the muon (g-2). Scalar leptoquark extensions of the SM are known to be able to address these anomalies, but generically give rise to lepton flavor violation or even proton decay. As a possible resolution, we introduce a lepton-flavored U(1) gauge symmetry to preserve the accidental symmetries...
In the last few years many exotic hadrons, which are states which do not appear to fit with the expectations for an ordinary $q\bar{q}$ or $qqq$ hadrons in the quark model, have been observed at various experimental facilities. Such results have motivated a series of studies focused on the description of the internal structure of the exotic hadrons as well as the proposition of new channels to...
We obtain the masses, the electromagnetic properties, and the parton distribution functions (PDFs) of the baryons (with a strange quark $\Lambda$ and a charm quark $\Lambda_c$, and their isospin triplet baryons) from a light-front effective Hamiltonian in the leading Fock sector. The effective Hamiltonian consists of the confining potential adopted from light-front holography in the transverse...
Novel studies of high energy photon-photon interactions at the LHeC [1] and FCC-eh, at the center-of-mass energy up to 1 TeV and beyond, will open new frontiers in the electroweak physics as well as in searches for physics beyond the Standard Model. Despite very high ep luminosities, the experimental conditions will be very favorable at these colliders - a negligible event pileup will...
Factorization formulas for scattering cross sections typically involve a parton-level cross section and PDFs associated with scattering hadrons. In hybrid kT-factorization, one PDF depends on the transverse momentum components of the parton besides the momentum component longitudinal to the hadron momentum. Furthermore, also in the partonic cross section these transverse components are not...
In this contribution, I will present a novel dynamical model for the pion based on the solution of the Bethe-Salpeter equation in Minkowski space. Our approach considers the pion as a bound state of a pair quark anti-quark interacting through the one-gluon exchange. The inputs of the model are the quark and gluon masses, and a scale parameter related to the extended quark-gluon vertex. Within...
One of the most interesting yet-to-be answered questions in Particle Physics is the nature of the Higgs Yukawa couplings and their universality. Key information in our understanding of this question arises from studying the coupling of the Higgs boson to second generation quarks. Some puzzles in the flavor sector and potential additional sources of CP violation could also have their origins in...
We present a parton-level study of electro-weak production of vector-boson pairs at the Large Hadron Collider, establishing the sensitivity to a set of dimension-six operators in the Standard Model Effective Field Theory (SMEFT). Different final states are statistically combined, and we discuss how the orthogonality and interdependence of different analyses must be considered to obtain the...
I summarize our attempts to describe HERA experimental data for the F_2 structure function using our implementation of the collinearly improved JIMWLK equation. I briefly describe the numerical framework based on Langevin reformulation of the JIMWLK equation and I illustrate the impact of the improvement on the dipole amplitude. I also comment on the influence of different functional forms of...
We obtain the light meson light-front wavefunctions (LFWFs) from the light-front QCD Hamiltonian, determined for their constituent quark-antiquark and quark-antiquark-gluon Fock components, together with a three-dimensional confinement. By fitting the model parameters to achieve the light-meson mass spectroscpy, the LFWFs provide a good quality description of the pion electromagnetic form...
In 2023, the sPHENIX detector at BNL’s Relativistic Heavy Ion Collider (RHIC) will begin measuring a suite of unique jet and heavy flavor observables with unprecedented statistics and kinematic reach at the RHIC energies using combined EM and hadronic calorimeters and high precision tracking. A MAPS-based vertex detector upgrade to sPHENIX, the MVTX, will provide a precise determination of the...
We discuss a method to study free protons and neutrons using $\nu(\bar \nu)$-hydrogen (H) Charged Current (CC) inelastic interactions using $\nu$ and $\bar \nu$ CC interactions on both H and nuclear targets. Probing free nucleons with (anti)neutrinos provides information about their internal structure, as well as a crucial input for the modeling of $\nu(\bar \nu)$-nucleus (A) interactions....
There have been numerous attempts, both theoretical and experimental, to understand the origin of the unexpectedly large transverse single spin asymmetry ($A_{N}$) for the inclusive hadron production at forward rapidities observed in $p^{\uparrow}$+p collisions at various center-of-mass energies. The twist-3 contributions in the collinear factorization framework and the...
We describe the phenomenological implications of a new heavy-quark mass scheme, called the Physical Scheme, that accounts for the effects of intrinsic heavy-quarks and provides a way to smoothly transition over the heavy-quark thresholds. We will present results for the DIS coefficient functions for $F_2$ and $F_L$ at NLO in the Physical Scheme showing that they reduce to the familiar...
Understanding the origin of the proton spin is one of the most fundamental and challenging questions in QCD. Much progress has been made since the first surprising results %on the spin structure of the proton by the EMC experiment in the late 1980s. However, for the helicity distributions of the proton, contributions from sea quarks, especially from the strange quark (anti-quark),...
Based on the light-cone wave function approach, we derive the the JIMWLK evolution equations with massive quarks. This is a generalization of previous work of NLO JIMWLK with massless quarks. The introduction of quark mass not only complicates relevant integrals due to massive energy denominators (propagators), but also gives rise to some divergences that are not present for cases with...
We argue that a wide range of phenomena which could be studies in UPC collisions at the LHC would be able to serve as a forerunner of studies to be performed within the small x program at EIC. This includes elastic and incoherent diffractive J/ψ production off nuclei where one would be able to reach x=10-5 direct photon production of charm dijets both in inclusive and diffractive modes....
Global interpretations of particle physics data in the context of the Standard Model Effective Field Theory (SMEFT) rely on the combination of a wide range of physical observables from many different processes. We present ongoing work towards the integration of unbinned measurements into such global SMEFT interpretations by means of machine learning tools. We use a deep-learning...
Future studies of nuclear physics will focus on the internal structure of the nucleon, which will require an Electron-Ion Collider (EIC) with high luminosity. Jets and heavy flavor quarks produced at the EIC will be key measurements to provide information on the hadronization process within nuclear matter, gluon saturation in nuclei, and the origin of mass. To achieve these physics goals, the...
Heavy flavor mass effects are significant in deep inelastic scattering (DIS) processes, and their systematic treatment becomes of more importance as we approach a one-percent accuracy in the determination of Parton Distribution Functions (PDFs). These effects are included through so-called variable flavor number schemes (VFNS), and most of the ingredients that are required by these schemes...
Spontaneous polarization of $\Lambda/\bar{\Lambda}$ has been observed over four decades ago, but still eludes a definitive explanation. One possible origin is the effect arising from polarizing fragmentation functions (PFFs), which describe the production of polarized hadrons from the fragmentation of an unpolarized parton. In 2019, the Belle experiment observed significant transverse...
The potential of the future Electron Ion Collider to constrain proton and nuclear collinear parton densities is explored using data simulated in the context of the proposed ATHENA detector. For the proton, projections relative to a `DIS-only’ approach are obtained in the HERAPDF2.0 framework. Substantial improvements in precision are observed at large x for valence quark, sea quark and gluon...
The talk will be about applications of on-shell techniques to the Standard Model Effective Field Theory (SMEFT). I will present a systematic classification of marginal operators in generic effective field theories and the computation of their anomalous dimensions using only on-shell data. Finally, I will show explicit results in the context of the SMEFT.
We consider a derivation of the hierarchy of correlators of ordered exponentials directly from the Lipatov's effective action
formulated in terms of interacting ordered exponentials.
The derivation of the Balitsky equation from the hierarchy is discussed as well as
the way the sub-leading eikonal corrections to the Balitsky equation arise from the transverse field contribution and...
In the Standard Model, CP violation in the Electroweak sector is parametrized by the Jarlskog Invariant. This is the order parameter of CP-violation, in the sense that it vanishes iff CP is conserved. When higher dimensional operators are allowed, and the Standard Model Effective Field Theory is constructed, numerous new sources for CP violation can appear. However, the description of CP...
We discuss models with Pomeron interactions in zero transverse dimensions. We show how to construct unitary models that allow for emission of more than one parton in one step of high energy evolution, and study some properties of particle distributions in these models.
We make a systematic study of $\Lambda$ hyperon polarizations in unpolarized lepton induced semi-inclusive reactions such as $e^-N\to e^-\Lambda X$ and $e^+e^-\to\Lambda h X$. We present the general form of cross sections in terms of structure functions obtained from a general kinematic analysis. This already shows that the produced hyperons can be polarized in three orthogonal directions,...
Heavy quark production in deep inelastic scattering receives a large contribution from the Photon Gluon Fusion process and thus provides a valuable tool to constrain the gluon distributions inside the nucleon/ion probed. Measurements of heavy flavor production can significantly improve the constraints on nuclear gluon distribution functions and gluon polarization in protons. Heavy flavor...
The anomalous dimensions of local quark and gluon operators determine the
scaling violations of the deep–inelastic scattering structure functions
and are therefore instrumental in the measurement of the strong coupling constant
and the evolution of the parton densities.
In this talk I present our recalculation of the 2- and 3-loop
anomalous dimensions with the traditional method of...
The proposed high-luminosity high-energy Electron-Ion Collider (EIC) will provide a clean environment to explore the proton/nuclear structure, search for gluon saturation and precisely determine the nuclear parton distribution functions (nPDFs) in a wide x-$Q^{2}$ phase space. Heavy flavor hadron and jet probes at the future EIC will allow us to better constrain the nPDFs within the poorly...
The computation of the structure functions for DIS can be tested across a range of energies with high accuracy and provides vital information for the evolution in the distribution of partons within a proton. We are currently investigating DIS at 4-loop, in particular the non-singlet sector.
Our approach consists of the determination large number of Mellin Moments, allowing for the...
Electroweak interactions assign a central role to the gauge group $SU(2)_L \times U(1)_Y$ , which is either realized linearly (SMEFT) or nonlinearly (e.g., HEFT) in the effective theory obtained when new physics above the electroweak scale is integrated out. Although the discovery of the Higgs boson has made SMEFT the default assumption, nonlinear realization remains possible.
I will...
Deep inelastic scattering on nuclei at the Electron-Ion Collider will open new opportunities to investigate the structure of matter. Heavy flavor-tagged jets are complementary probes of the partonic composition and transport coefficients of large nuclei, but introduce a new mass scale that modifies the structure of parton showers and must be carefully accounted for in perturbative...
The sPHENIX detector currently under construction at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) is designed to significantly advance studies of the microscopic nature of nuclear matter. The experiment incorporates full azimuth vertexing, tracking, and a complete set of electromagnetic and hadronic calorimeters over the pseudorapidity range |η| < 1.1. This powerful...
We explore the interplay between the HEFT and SMEFT theories. Whereas the SMEFT has become the standard in the field of LHC phenomenology, the HEFT provides a more flexible description of the electroweak sector. In particular, we discuss various aspects of (multi-) Higgs production from longitudinal electroweak gauge bosons $W_LW_L\to n\times h$ in the TeV region, and compare predictions from...
The Electron-Ion Collider (EIC) is a cutting-edge accelerator experiment, which will be uniquely poised to address questions related to the origin of mass and spin of the nucleon and the emergent properties of dense systems of gluons. Detector design and R&D are currently ongoing for proposed experiments at the EIC that will be realized approximately 10 years from now. These experiments...
We present results of all-charm tetraquark study in the Front Form of Hamiltonian dynamics using many-body basis function approach known as Basis Light Front Quantization. We take into account only color-singlet states but make no restriction on possible tetraquark structures. The model Hamiltonian contains transverse and longitudinal confining potentials and one-gluon-exchange effective...
Recent results from the proton-proton collision data taken by the ATLAS experiment on exotic resonances will be presented. A study of J/psi p resonances in the Lambda_b -> J/psi p K decays with large m(pK) invariant masses will be reported. Studies of Z_c states in B-meson decays with the Run 2 data at 13 TeV will also be discussed. Searches for exotic resonances in 4 muon final states will be...
We discuss the impact of the new LHCb fixed-target $p\!+\!^{4}\!He$ data for $D^0/{\bar D}^0$ production on the intrinsic $c \bar c$ component in the nucleon wave function. Within the scenario presented here neither the traditional gluon-gluon fusion or quark-antiquark annihilation mechanisms calculated in the $k_T$-factorization approach nor their counterparts from the collinear...
Correlations between charged particles provide important insight about hadronization processes. We present recent results on Bose-Einstein two-particle correlation using ATLAS data at the center-of-mass energy of 13 TeV. Also, if available, the analysis of the momentum difference between charged hadrons in pp, p-lead, and lead-lead collisions of various energies is performed in order to study...
High $p_T$ direct photons produced in initial hard scattering are not affected by the colored medium formed in heavy ion collisions. This has been observed in large-on-large ion collisions, where, in contrast, jets and final state hadrons show energy loss, measured via the nuclear modification factor that compares the observed yields to the expected yield from p+p scaled by the number of...
We present a Leading-Order PDFs fitting within the CT18 framework, i.e., CT18 LO PDFs. To improve the fitting results, we imposed two treatments: 1) exclude 5 data sets, which cannot be correctly described with LO QCD theory, from the CT18 global data set; 2) apply a K-factor to mimic the NLO QCD corrections to Drell-Yan processes. The strong coupling as input for CT18 LO is fixed to be its...
The Electron-Ion Collider is a future collider planned to be built at BNL in about 2030. It will provide physicists with high luminosity and highly polarized beams of electrons, protons and ions with a wide range of nuclei species at different energies, covering an extensive kinematic range. The EIC physical goals include measuring the generalized parton distribution from Deeply Virtual...
To meet new TDAQ buffering requirements and withstand the high expected radiation doses at the high-luminosity LHC, the ATLAS Liquid Argon Calorimeter readout electronics will be upgraded. The triangular calorimeter signals are amplified and shaped by analogue electronics over a dynamic range of 16 bits, with low noise and excellent linearity. Developments of low-power preamplifiers and...
In this work, we investigate the dependence of proton $k_t$-factorization structure functions on the different sets of parton distribution functions (PDFs), i.e. MMHT2014, CJ15lo, CTEQ6l1, HERAPDF15, MSTW2008 and MSHT20. The Kimber-Martin-Ryskin (KMR) unintegrated parton distribution functions (UPDFs), which can use the above PDFs sets as input, are considered to calculate the
proton...
We present a phenomenological study of the single top (anti-)quark production with leptonic decays at the Large Hadron electron Collider (LHeC) at the next-to-leading-order (NLO) in QCD. We focus on various differential distributions in a fiducial region. The NLO corrections can reduce the fiducial cross section by 14%. We find the NLO predictions exhibit strong stability under scale...
The current work is used to explore the structure of hot and dense system quark gluon plasma (QGP) in order to deal with the dynamics of quarks and gluons in magnetized field. Since a huge and intense magnetic field is expected to be produce at RHIC and LHC, we calculate the equation of states (EoS) in the presence of time dependent magnetic fields with the medium effects of quarks and gluons...
Hard Exclusive Meson Production (HEMP) and Deeply Virtual Compton Scattering (DVCS) are very promising reactions to access Generalized Parton Distributions (GPDs). Such exclusive measurements were performed at COMPASS in 2016 and 2017 at the M2 beamline of the CERN SPS using the 160 GeV muon beam scattering off a 2.5 m long liquid hydrogen target surrounded by a barrel-shaped time-of-flight...
Jets are collimated bunches of hadrons ubiquitous in the detectors at the LHC. Studying the internal structure of these objects is essential to identify the original objects that originate the jet and to understand the underlying physical process. An important category of Jet Substructure (JSS) observables are Jet Angularities which have been recently calculated in resummed perturbation...
We study the production of $2\pi^+2\pi^-$ in ultra-peripheral heavy-ion collisions at RHIC and LHC energies. The recent H1 preliminary data [1] are utilized to improve the description of the poorly known $\gamma p \to 4\pi^\pm p$ process. Predictions for photon-nucleus interactions were calculated for various excited states of $\rho$ meson. We will present an agreement of theory with the...
The search for physics beyond the Standard Model (BSM) is one of the main goals of the LHC. Compared to standard proton-proton collision studies, heavy-ion collisions provide unique and complementary means to search for new phenomena. In particular, ultra-peripheral collisions (UPCs) of heavy ions offer a natural environment for the studies of photon-mediated processes, such as light-by-light...
We study the non-perturbative leading twist generalized parton quasi distributions (qGPDs) and transversity generalized quasi distributions (qtGPDs) of the pion in the framework chiral quark models. Such quantities can be directly accessed in lattice QCD simulations, hence our model predictions gain practical significance. We also explore the corresponding Ioffe distributions and various form...
We present the first-ever global QCD analysis of the semi-inclusive DIS data using Monte Carlo techniques to extract the worm-gear TMD $g_{1T}$. The relevant data are available from HERMES, COMPASS and JLab. We compare our results for $g_{1T}$ with different theoretical approaches such as the large-$N_c$ approximation, the Wandzura-Wilczek-type approximation, and lattice QCD.
The hard scatter, tagged by an electroweak boson or a jet, fixes initial properties of the showering partons prior to interactions with the QGP. In large systems, modification to the parton fragmentation is an expected consequence of the strong medium interactions, while in small systems, indications of QGP droplet formation are juxtaposed with previous observations of minimal jet quenching....
We present a measurement of the inclusive jet production in proton-proton collisions at the LHC at $\sqrt{s}=13~TeV$. The double-differential cross sections are measured as a function of the jet transverse momentum $p_T$ and the absolute jet rapidity $|y|$. The anti-$k_t$ clustering algorithm is used with distance parameter of 0.4 (0.7) in a phase space region with jet $p_T$ from $97~GeV$ up...
Deep inelastic scatterings (DIS) of heavy nuclei at future electron-ion colliders start an exciting new era for precision measurement of the partonic structures of the cold nuclear matter. The transverse-momentum dependent (TMD) parton distributions in heavy nuclei can be uniquely studied from nuclear modifications of jet fragmentation and hadron production in semi-inclusive DIS. In the...
Over the last decades, the theoretical picture of how hadronic jets interact with nuclear matter has been extended to account for the medium’s finite longitudinal length and expansion. However, only recently a first-principle approach has been developed that allows to couple the jet evolution to the medium flow and anisotropic structure in the dilute limit. In this talk, we will show how to...
Hypernuclei are bound nuclear systems of correlated nucleons and hyperons. Therefore, the production of hypernuclei in heavy-ion collisions provides an experimental avenue for studying hyperon$-$nucleon (Y-N) interaction, which is an important ingredient, not only in the equation-of-state of astrophysical objects such as neutron stars, but also in the description of the hadronic phase of a...
Tests of Lorentz invariance continue to expand and challenge our understanding of spacetime symmetries in and beyond the Standard Model and General Relativity. Using a model-independent framework based on effective field theory, generic deviations from exact Lorentz invariance, CPT invariance, and other fundamental symmetries can be studied in a wide class of physical systems covering a broad...
Within the Phase-II upgrade of the LHC, the readout electronics of the ATLAS LAr Calorimeters is prepared for high luminosity operation expecting a pile-up of up to 200 simultaneous pp interactions. Moreover, the calorimeter signals of up to 25 subsequent collisions are overlapping, which increases the difficulty of energy reconstruction. Real-time processing of digitized pulses sampled at 40...
We study production of one, two, three and four isolated photons at the energy of Large Hadron Collider in the Parton Reggeization Approach [1,2], which is based on high-energy factorization, Lipatov effective theory [3] and new unintegrated PDFs, obtained in modified multi-Regge kinematics approximation for QCD scattering amplitudes [4]. It is shown that experimental data from ATLAS and CMS...
The LHCb spectrometer has the unique capability to function as a fixed-target experiment by injecting gas into the LHC beampipe while proton or ion beams are circulating. The resulting beam+gas collisions cover an unexplored energy range that is above previous fixed-target experiments, but below the top RHIC energy for AA collisions. Here we present new results on antiproton and charm...
Background modelling is one of the main challenges of particle physics analyses at hadron colliders. Commonly employed strategies are the use of simulations based on Monte Carlo event generators or the use of parametric methods. However, sufficiently accurate simulations are not always available or may be computationally costly to produce in high statistics, leading to uncertainties that can...
The feasibility of observing true tauonium, the ground bound-state of two tau leptons $\mathcal{T}_0\equiv(\tau^+\tau^-)$, via photon-photon collisions at current and future colliders is studied. The production cross sections of the process $\gamma\gamma\to\mathcal{T}_0\to\gamma\gamma$ ---as well as those of all relevant backgrounds: spin-0 and 2 charmonium resonances decaying to diphotons,...
The European Strategy for Particle Physics ESPP has recommended the financial and technical feasibility of the FCC colliders and their infrastructure to be carried out for its next upgrade around 2026. The integral FCC program combines in the same 100km infrastructure a high luminosity Higgs and Electroweak factory e+e- collider, FCC-ee, followed by a 100 TeV hadron collider. With its high...
ATHENA is a general-purpose detector designed to deliver the full physics program of the Electron-Ion Collider (EIC). Particle identification (PID) at the EIC is an essential asset as well as a challenge: the PID systems have to provide excellent separation of pions, kaons, and protons over a large phase space with significant pion/electron suppression. ATHENA addresses the physics...
We present a new determination of unpolarised charged pion and kaon fragmentation functions from a set of single-inclusive electron-positron annihilation and lepton-nucleon semi-inclusive deep-inelastic scattering data. The determination includes next-to-next-to-leading order QCD corrections to both processes, and is carried out in a framework that combines a neural network parametrisation of...
We discuss a method to study free protons and neutrons using $\nu(\bar \nu)$-hydrogen (H) Charged Current (CC) inelastic interactions using $\nu$ and $\bar \nu$ CC interactions on both H and nuclear targets. Probing free nucleons with (anti)neutrinos provides information about their internal structure, as well as a crucial input for the modeling of $\nu(\bar \nu)$-nucleus (A) interactions....
We consider the production of $Z$ bosons associated with heavy (charm and beauty) jets at the LHC energies using two scenarios based on the transverse momentum dependent (TMD) parton densities in a proton. The first of them employs the Catani-Ciafaloni-Fiorani-Marchesini gluon evolution and is implemented in the Monte-Carlo event generator \textsc{pegasus}. Here, the heavy quarks are always...
To resolve the long-standing discrepancy between the precision measurement of bottom quark forward-backward asymmetry at LEP/SLC and the Standard Model prediction, we propose a novel method to probe the $Zb\bar{b}$ coupling by measuring the (average jet charge weighted) single-spin asymmetry of the polarized lepton cross section in neutral current DIS processes with a b-tagged jet at HERA and...
The ALICE experiment aims at investigating the properties of strongly-interacting matter in extreme conditions of temperature and energy density where the quark-gluon plasma (QGP) is formed. Heavy quarks (charm and beauty quarks), mostly produced via hard partonic scattering processes in the very early stage of the collisions, are efficient probes of the properties and dynamics of the QGP...
A phenomenological study of the isolated photon and dilepton production in association with leading hadron in $pp$ and $pA$ collisions at RHIC and LHC energies is performed. Using the color dipole approach we investigate the production cross section differential in the
transverse momentum of the photon (di-lepton pair) considering three different phenomenological models for the universal...
The potential of the future Electron Ion Collider to constrain proton and nuclear collinear parton densities is explored using data simulated in the context of the proposed ATHENA detector. For the proton, projections relative to a `DIS-only’ approach are obtained in the HERAPDF2.0 framework. Substantial improvements in precision are observed at large x for valence quark, sea quark and gluon...
Ultrarelativistic nuclear collisions provide an excellent opportunity to understand the properties of the deconfined medium of quarks and gluons, the so-called quark-gluon plasma. Beauty quarks are produced by hard parton-parton scatterings in the initial stages of the nuclear collisions, and experience the full medium evolution. Measurements of open-beauty hadrons can provide information on...
The differential cross section of proton-proton elastic scattering, as a function of the magnitude of the four-momentum transfer squared |t|, evolves in a consistent manner with $\sqrt{s}$ at LHC energies. The "dip" and "bump" structures change their positions in $|t|$ as a function of $\sqrt{s}$ and the slope at low values of $|t|$ and integrated elastic cross section grow with $\sqrt{s}$....
To address the incompleteness of the Standard Model (SM), many models, e.g compositeness, extra dimensions, have predicted the existence of new resonances at the LHC in the final state of a photon and a jet. If such a resonance exists, the signal would appear as a bump on top of the smooth invariant mass distribution of the SM background processes. A search is presented for new resonances...
Many new physics models predict the existence of Higgs-like particles decaying into two bosons (W, Z, photon, or Higgs bosons) making these important signatures in the search for new physics. Searches for V??, VV, and VH resonances have been performed in various final states. In some of these searches, jet substructure techniques are used to disentangle the hadronic decay products in highly...
Precise theoretical predictions of physical processes at hadron colliders are a fundamental ingredient of the LHC precision programme. In the production of a heavy quark pair in proton-proton collisions, the final-state invariant mass can be much smaller than the collider energy. Under these conditions, high-energy logarithms may spoil the perturbativity of fixed order perturbation theory....
Motivated by the approval of the Electron-Ion Collider, we report the status of modeling electron-ion scattering at NLO in QCD with the general-purpose simulation framework MadGraph5_aMC@NLO.
The sPHENIX detector currently under construction at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) is designed to significantly advance studies of the microscopic nature of nuclear matter. The experiment incorporates full azimuth vertexing, tracking, and a complete set of electromagnetic and hadronic calorimeters over the pseudorapidity range |η| < 1.1. This powerful...
Here, we present the extraction of the Parton Distribution Functions (PDFs) at
low x and at the next-to-leading order (NLO) approximation.
We show that the "sea quark distribution functions" have self-similar behavior or the "Fractal" behavior with fixed exponent at $x<0.01$. To this end, a simple parametrization for the sea quarks PDFs based on the "Fractal" approach is considered....
The Spin Physics Detector project at the future NICA complex at JINR
(Dubna, Russia) aims to investigate the nucleon spin structure and
polarization phenomena in collisions of longitudinally and
transversely polarized protons and deuterons at $\sqrt{s}$ up to 27
GeV and luminosity up to 10$^{32}$ cm$^{-2}$ s$^{-1}$.In particular
such probes as charmonia, prompt photons, and open charm...
Experiments at the future Electron-Ion Collider (EIC) pose stringent requirements on the tracking system for the measurement of the scattered electron and charged particles produced in the collision, as well as the position of the collision point and any decay vertices of hadrons containing heavy quarks. Monolithic Active Pixel Sensors (MAPS) offer the possibility of high granularity in...
This talk presents ATLAS recent measurements of distributions sensitive to Underlying event, the hadronic activity observed in relationship with the hard scattering in the event. The rates and the total transverse momentum was measured for Kaons, Lambda baryons and their ratios as a function of the leading track-jet and is compared to MC predictions which in general fail to describe the data....
Transverse momentum broadening (TMB) of energetic partons in QCD matter plays a central role in a variety of processes studied at colliders to probe QCD, ranging from TMD gluon distributions that encode information on the 3D structure of the proton and nuclei in electron-proton or proton-proton collisions to jet suppression in heavy ion collisions.
In this talk, based on [1,2], we study the...
Ultra-peripheral collisions of heavy ions (UPCs) serve as a valuable source of experimental data for studies of photon-photon interactions. One of the latest examples is the evidence of light-by-light scattering process (LbyL) first established by the CMS and ATLAS collablorations at the LHC. UPCs were also proposed as a tool for searches of effects of physics beyond the Standard Model (BSM),...
The strong electromagnetic field generated by the colliding nuclei in heavy-ion collisions can be represented by a spectrum of photons, leading to photon-induced interactions. While such interactions are traditionally studied in ultra-peripheral collisions (UPC) without any nuclear overlap, significant enhancements of dilepton pair and J/$\psi$ production at very low transverse momentum...
