Publications

Order by: publication date number of citations

• Heavy Flavor and Jet Studies for the Future Electron-Ion Collider to Explore the Hadronization Process

  Xuan Li

  SciPost Phys. Proc. 8, 076 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Heavy flavor production at the future Electron-Ion Collider (EIC) will allow us to precisely determine the quark/gluon fragmentation processes in vacuum and the nuclear medium especially within the poorly constrained kinematic region. Heavy flavor hadron and jet reconstruction with the recent EIC detector design have been studies in simulation. Results of corresponding physics projections such as the flavor dependent hadron nuclear modification factor $R_{eA}$ in electron+nucleus collisions will be shown. The statistical precision obtained by these proposed heavy flavor measurements for the future EIC provides a strong discriminating power in separating different theoretical predictions.

• Studying hadronization at LHCb

  Sookhyun Lee

  SciPost Phys. Proc. 8, 075 (2022) · published 12 July 2022 | Toggle abstract · pdf

  LHCb is a fully instrumented forward spectrometer with particle identification and muon reconstruction covering the pseudorapidity ($eta$) range from 2 to 5. Its full jet reconstruc- tion capability makes the LHCb experiment a suitable venue to explore jet substructure observables, particularly formation of hadrons and heavy quarkonia resonances inside jets. This contribution presents a brief overview of ongoing research program and dis- cusses recent results on non-identified charged hadron distributions in Z-tagged jets and charmonium distributions within jets. Future works towards furthering the knowledge of hadronizion are also discussed.

• Physics from Photons at the LHC

  Lucian Harland-Lang

  SciPost Phys. Proc. 8, 072 (2022) · published 12 July 2022 | Toggle abstract · pdf

  LHC collisions can act as a source of photons in the initial state. This mechanism plays an important role in the production of particles with electroweak couplings, and a precise account of photon-initiated (PI) production at the LHC is a key ingredient in the LHC precision physics programme. I will discuss the possibility of modelling PI processes directly via the structure function approach. This can provide percent level precision in the production cross sections, and is therefore well positioned to account for LHC precision requirements. This formalism in addition allows one to make use of another useful feature of photons, namely that they are colour-singlet and can often be emitted elastically (or quasi-elastically) from the proton. I will discuss recent work on applications of the structure function approach to precision calculations of PI production in the inclusive mode, and to `exclusive' processes with rapidity gaps, which can provide a unique probe of the Standard Model and physics beyond it.

• Opportunities for inclusive diffraction at EIC

  Wojciech Slominski, Nestor Armesto, Paul R. Newman, Anna Stasto

  SciPost Phys. Proc. 8, 069 (2022) · published 12 July 2022 | Toggle abstract · pdf

  The possibilities for inclusive diffraction in the Electron Ion Collider, EIC, in the US, are analyzed. We find that thanks to the excellent forward proton tagging, the EIC will be able to access a wider kinematical range of longitudinal momentum fraction and momentum transfer of the leading proton than at HERA. This opens up the possibility to measure subleading diffractive exchanges. The extended $t$-range would allow the precise extraction of 4-dimensional reduced cross section in diffraction. In addition, the varying beam energy setups at the EIC would allow for precise measurements of the longitudinal diffractive structure function.

• Hard exclusive $\pi^{+}n$ electro production beam spin asymmetries off the proton in the GPD and TDA regimes

  S. Diehl for the CLAS collaboration

  SciPost Phys. Proc. 8, 066 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Hard exclusive $\pi^{+}$n electro-production can be used to gain access to the 3D nucleon structure. The QCD factorisation mechanism in the "nearly forward region" ($t/Q^{2}$ small) allows a description by Generalized Parton Distributions (GPDs), while for the "nearly backward" kinematic region ($u/Q^{2}$ small) a description based on nucleon to pion transitions (TDAs) is available. The paper presents a measurement of single beam spin asymmetries to extract the $A^{\sin\phi}_{LU}$ moments and the related cross section ratio $\sigma_{LT^\prime}/\sigma_{0}$ from the hard exclusive $\pi^{+}$ channel off the unpolarized hydrogen target in a wide range of kinematics based on data taken with the CLAS spectrometer at Jefferson Lab. In addition, under forward angles a detailed multidimensional study will be presented based on CLAS12 data and compared to theoretical predictions.

• First measurement of the forward rapidity gap distribution in pPb collisions at 8 TeV

  Dmitry E. Sosnov

  SciPost Phys. Proc. 8, 065 (2022) · published 12 July 2022 | Toggle abstract · pdf

  We present the forward rapidity gap spectra from proton-lead collisions for both I\!P-Pb and I\!P-p topologies measured at the CMS at a center-of-mass energy of 8.16 TeV. For the I\!P-Pb topology, the cross-section predicted by EPOS-LHC is a factor of two lower than the data while has reasonable description of the spectrum shape. For the I\!P-p topology, the EPOS-LHC, QGSJET~II and HIJING predictions are significantly lower than the data, what can be explained by a contribution of ultra-peripheral photoproduction events. The obtained data may be of significant input for understanding the high energy limit of QCD and modeling cosmic ray air showers.

• Nucleon and pion PDFs: large-x asymptotics meets functional mimicry

  Aurore Courtoy, Pavel M. Nadolsky

  SciPost Phys. Proc. 8, 063 (2022) · published 12 July 2022 | Toggle abstract · pdf

  We review strategies to unveil the primordial large-$x$ structure of the nucleons as well as the pion from hard-scattering experiments. Ideas are presented for learning about the $x\to 1$ limit of nonperturbative QCD dynamics at energy scales of order 1 GeV from collider experiments at much higher scales. The behavior of parton distributions at $x\to 1$ predicted by the quark counting rules and other low-energy theoretical approaches is contrasted with phenomenological PDFs. Polynomial mimicry of PDF parametrizations is one of many factors that influence the apparent power of the $(1-x)$ falloff. We discuss implications of the mimicry for the large-$x$ falloff of the pion PDFs.

• Open strange meson $K^\pm_1$ in hot and dense nuclear matter

  Rajesh Kumar, Arvind Kumar

  SciPost Phys. Proc. 8, 055 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Using the unification of the chiral SU(3) model and QCD sum rules, we deduce the in-medium properties of $K^\pm_1$ meson. Within the chiral SU(3) model, medium modified gluon and quark condensates are evaluated through their interactions with the scalar fields ($\sigma$, $\zeta$, $\delta$, and $\chi$). These condensates are further used as input in the Borel transformed equations of QCD sum rules to evaluate the in-medium mass of strange $K^\pm_1$ meson. The in-medium property of the above meson can be used to study the restoration of chiral symmetry in nuclear matter.

• Multi-particle production in proton-nucleus collisions in the Color Glass Condensate

  Pedro Augusto Agostini Infante, Tolga Altinoluk, Nestor Armesto

  SciPost Phys. Proc. 8, 054 (2022) · published 12 July 2022 | Toggle abstract · pdf

  We compute multi-gluon production in the Color Glass Condensate approach in dilute-dense collisions, p$A$. We include the contributions that are leading in the overlap area of the collision but keep all orders in the expansion in the number of colors. We use a form of the Lipatov vertices that leads to the Wigner function approach for the projectile previously employed, that we generalise to take into account quantum correlations in the projectile wave function. We compute four gluon correlations and we find that the second order four particle cumulant is negative, so a sensible second Fourier azimuthal coefficient can be defined.

• Measuring the light meson nuclear modification factor in p-Pb collisions over an unprecedented $p_{\text{T}}$ range with ALICE

  Joshua König

  SciPost Phys. Proc. 8, 048 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Differential invariant cross sections of light neutral mesons in p-Pb collisions at $\sqrt{s_{\text{NN}}}$ = 8.16 TeV and in pp collisions at $\sqrt{s}$ = 8 TeV have been measured up to very high transverse momentum ($p_{\text{T}}$). By combining independent reconstruction techniques available in ALICE using the EMCal and PHOS calorimeters as well as the central barrel tracking detectors, the combined spectra cover almost two orders of magnitude in $p_{\rm T}$ for the $\pi^{0}$ meson. The nuclear modification factor $R_{\text{pPb}}$ has been measured for the $\pi^{0}$ and $\eta$ mesons and is found to be consistent with NLO pQCD, CGC and energy loss calculations. Comparisons to the $R_{\text{pPb}}$ of $\pi^{0}$ measured in $\sqrt{s_{\text{NN}}}$ = 5.02 TeV hint at a stronger suppression at low $p_{\rm T}$ with increasing collision energy.