Conveners
WG4: QCD with Heavy Flavours and Hadronic Final States: Jet Session 1: inclusive jets and substructure
- Olga Evdokimov (University of Illinois at Chicago (US))
- Xuan Li (Los Alamos National Laboratory)
- Maria Vittoria Garzelli
WG4: QCD with Heavy Flavours and Hadronic Final States: Jet Session 2: heavy-flavour jets
- Xuan Li (Los Alamos National Laboratory)
- Maria Vittoria Garzelli
- Olga Evdokimov (University of Illinois at Chicago (US))
WG4: QCD with Heavy Flavours and Hadronic Final States: Jet Session 3: jet associated production
- Xuan Li (Los Alamos National Laboratory)
- Maria Vittoria Garzelli
- Olga Evdokimov (University of Illinois at Chicago (US))
WG4: QCD with Heavy Flavours and Hadronic Final States: Jet Session 4: jets in DIS
- Olga Evdokimov (University of Illinois at Chicago (US))
- Maria Vittoria Garzelli
- Xuan Li (Los Alamos National Laboratory)
WG4: QCD with Heavy Flavours and Hadronic Final States: Quarkonia from light systems onwards
- Maria Vittoria Garzelli
- Olga Evdokimov (University of Illinois at Chicago (US))
- Xuan Li (Los Alamos National Laboratory)
WG4: QCD with Heavy Flavours and Hadronic Final States: Open heavy flavour (charm and bottom)
- Xuan Li (Los Alamos National Laboratory)
- Olga Evdokimov (University of Illinois at Chicago (US))
- Maria Vittoria Garzelli
WG4: QCD with Heavy Flavours and Hadronic Final States: Quarkonia and Exotics
- Olga Evdokimov (University of Illinois at Chicago (US))
- Maria Vittoria Garzelli
- Xuan Li (Los Alamos National Laboratory)
WG4: QCD with Heavy Flavours and Hadronic Final States: Heavy Flavour Future
- Maria Vittoria Garzelli
- Olga Evdokimov (University of Illinois at Chicago (US))
- Xuan Li (Los Alamos National Laboratory)
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...
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...
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 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...
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...
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...
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...
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...
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 ...
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...
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...
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...
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...
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...
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...
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 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...
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 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...
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...
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...
$J/\psi$ 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...
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....
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...
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...
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 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...
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,...
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.
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...
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...
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....
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...
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 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....
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 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 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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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....
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...
