Conveners
QCD: QCD, Hadron Spectroscopy, and Exotics: QCD-1
- Martha Constantinou (Temple University)
- Justin Stevens (William & Mary)
- Tomasz Skwarnicki (Syracuse University)
QCD: QCD, Hadron Spectroscopy, and Exotics: Joint QCD - PDF
- Tomasz Skwarnicki (Syracuse University)
- Maria Zurek (Argonne National Laboratory)
- Justin Stevens (William & Mary)
- Martha Constantinou (Temple University)
- Maria Pia Zurita (University of Regensburg)
QCD: QCD, Hadron Spectroscopy, and Exotics: QCD-2
- Justin Stevens (William & Mary)
- Tomasz Skwarnicki (Syracuse University)
- Martha Constantinou (Temple University)
Description
QCD, Hadron Spectroscopy, and Exotics
LHCb is at the forefront of searches for new exotic hadrons through spectroscopy in high energy physics and the recent results published from proton-proton collision data taken by the experiment will be presented. In particular, the observation of a $J/\psi\Lambda$ resonance in $B^{-}\to J/\psi\Lambda\bar{p}$ decays consistent with a strange pentaquark, and two new tetraquarks (one doubly...
Many exotic resonances have been recently observed at LHC. In this report a search for low-mass structures in the JPsi/JPsi mass spectrum in pp collisions at sqrt(s)=13TeV is presented. The new results are based on data collected by the CMS experiment during the full Run II.
A production and decay model that incorporates theoretical and previously unrecognized experimental constraints on the LHCb pentaquark states is presented. The model satisfies all constraints and successfully fits the entire invariant mass distribution (unlike previous work). We find strong evidence for Sigma_c D molecular states along with threshold cusp and triangle singularities....
The strong interaction between quarks and gluons, from which hadrons are built, is theoretically described by quantum chromodynamics. However, the role of gluons and how they affect the properties of hadrons is still unresolved. The discovery of several unexpected and possibly exotic hadrons in recent years highlights the need for precise spectroscopic measurements to understand the nature of...
Parton dynamics inside the proton and hadronization are key areas of research in Quantum ChromoDynamics (QCD) at LHCb at the Large Hadron Collider. A large hard scale above the electroweak scale reached by hadron collisions at unprecedentedly high energies enables measurements sensitive to multiple scales that potentially explain interesting nonperturbative dynamics inside the proton and in...
The transverse-momentum-dependent parton distributions (TMDs) provide a 3D imaging of the proton and other hadrons in high-energy scattering experiments, such as those at Fermilab, Jefferson Lab, RHIC and LHC. Recent years have seen significant progress in the global fitting of TMDs from experiments, and along with that is a lattice QCD program aiming at first-principles calculation of these...
A detailed understanding of the proton's properties is incomplete without the knowledge of the transverse spin structure of its constituent quarks, which may be accessed in proton-proton collisions via hadron-in-jet and di-hadron asymmetries. Both observables couple the quark transversity distribution to a spin dependent fragmentation function. For the di-hadron channel it is the collinear...
Nuclear parton distribution functions (nPDF) play a crucial role in the interpretation of scattering data taken in proton-nucleus and nucleus-nucleus collisions at the Relativistic Heavy Ion Collider (RHIC), the Large Hadron Collider (LHC) and in the near future at the Electron-Ion Collider (EIC). However, analyses of these nPDFs are still far away from the precision obtained in free proton...
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 production data to address this issue. To constrain the gluon nPDF further, particularly at low x, we present two new global analyses adding single...
Using data samples with a total integrated luminosity of more than 20 fb^-1 at center-of-mass energies between 4 and 5 GeV, charmonium(-like) states can be investigated in high detail with the BESIII experiment. Here, we will present past accomplishments and recent highlights, including studies on a Zcs candidate, cross section measurements of both hidden- and open-charm production and...
Results of the first global and unitary analysis of e+e- to b b-bar are presented. We find strong evidence for the new Upsilon(10750). Branching fractions are found to deviate significantly from older results. Implications of this for modelling are discussed.
Accessing the hadron spectrum from Quantum ChromoDynamics (QCD) poses several challenges given its non-perturbative nature and the fact that most states couple to multi-particle decay modes. Although challenging, advances in both theoretical and numerical techniques have allowed us to determine few-body systems directly from QCD. A synergistic approach between lattice QCD and scattering theory...
We construct the light-front wavefunctions (LFWFs) of charmonium and bottomonium states on a small-sized basis function representation. In this work, we modeled the LFWFs for four charmonium states and three bottomonium states, $\eta_c$, $J/\psi$, $\psi'$, and $\psi(3770)$,as well as $\eta_b$, $\Upsilon$, $\Upsilon(2s)$, based on a set of orthonormal basis functions.The basis functions are...
Recent results on exotic resonances obtained from the proton-proton collision data taken by the ATLAS experiment will be presented. A study of $J/\psi\ p$ resonances in $\Lambda_b \to J/\psi\ p\ K$ 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 be discussed. Searches for exotic resonances in 4 muon...
