Publications

Order by: publication date number of citations

• Accessing CKM suppressed top decays at the LHC

  Darius A. Faroughy, Jernej F. Kamenik, Manuel Szewc, Jure Zupan

  SciPost Phys. 16, 131 (2024) · published 24 May 2024 | Toggle abstract · pdf

  We propose an extension of the existing experimental strategy for measuring branching fractions of top quark decays, targeting specifically $t\to j_q W$, where $j_q$ is a light quark jet. The improved strategy uses orthogonal $b$- and $q$-taggers, and adds a new observable, the number of light-quark-tagged jets, to the already commonly used observable, the fraction of $b$-tagged jets in an event. Careful inclusion of the additional complementary observable significantly increases the expected statistical power of the analysis, with the possibility of excluding $|V_{tb}|=1$ at $95\%$ C.L. at the HL-LHC, and accessing directly the standard model value of $|V_{td}|^2+|V_{ts}|^2$.

• Production mechanisms of open heavy flavor mesons in high-multiplicity events

  Marat Siddikov, Ivan Schmidt

  SciPost Phys. Proc. 8, 096 (2022) · published 13 July 2022 | Toggle abstract · pdf

  In this proceeding we discuss different mechanisms of open-heavy flavor meson production which contribute to inclusive and single diffractive cross-sections. For the case of inclusive production we demonstrate that the three-Pomeron fusion is significant for the $D$-meson production in the kinematics of small transverse momenta $p_{T}$, as well as in large-multiplicity events. Its inclusion allows to improve significantly the description of experimental data. We also analyzed the diffractive production and found that due to gap survival factors it constitutes 0.5\textendash 2 per cent of the inclusive production. The expected dependence on event multiplicity in this channel is significantly milder than for inclusive case.

• Simultaneous Extraction of Unpolarized PDFs and Nuclear Effects

  C. Cocuzza, A. Metz, N. Sato

  SciPost Phys. Proc. 8, 098 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We present a new global QCD analysis of unpolarized parton distribution functions (PDFs) and nuclear effects including for the first time data from the SeaQuest and MARATHON experiments in addition to high-energy weak-boson-production data from the Tevatron and Large Hadron Collider. Simultaneously extracting the PDFs and nuclear effects, we examine the impact of the SeaQuest and MARATHON data on the light-quark sea asymmetry and the EMC ratios of deuterium, helium, and tritium.

• A new method to extract the valence transversity distributions

  Mauro Anselmino, Raj Kishore, Asmita Mukherjee

  SciPost Phys. Proc. 8, 052 (2022) · published 12 July 2022 | Toggle abstract · pdf

  A new method is suggested for the extraction of $u$-quark and $d$-quark transversity distributions, using single spin asymmetry (SSA) data in semi-inclusive deep inelastic scattering (SIDIS) processes, where they couple to the Collins or the di-hadron fragmentation functions. We discuss a recent suggestion to extract the transversity distribution using the concept of difference asymmetries and their ratios, which avoids the requirement of Collins function. We suggest new measurements, involving ratios of polarized cross-sections, that would directly probe the ratio $h_1^{d_v}/h_1^{u_v}$. We also show some numerical estimates.

• Three-loop soft anomalous dimensions for top-quark processes

  Nikolaos Kidonakis

  SciPost Phys. Proc. 8, 104 (2022) · published 13 July 2022 | Toggle abstract · pdf

  I present results for soft anomalous dimensions through three loops for several processes involving the production of top quarks. In particular, I discuss single-top and top-pair production. I also present some numerical results for double-differential distributions in $t{\bar t}$ production through approximate N$^3$LO.

• Shadow generalized parton distributions: a practical approach to the deconvolution problem of DVCS

  V. Bertone, H. Dutrieux, C. Mezrag, H. Moutarde, P. Sznajder

  SciPost Phys. Proc. 8, 107 (2022) · published 13 July 2022 | Toggle abstract · pdf

  Deeply virtual Compton scattering (DVCS) attracts a lot of interest due to its sensitivity to generalized parton distributions (GPDs) which provide a rich access to the partonic structure of hadrons. However, the practical extraction of GPDs for this channel requires a deconvolution procedure, whose feasibility has been disputed. We provide a practical approach to this problem based on a next-to-leading order analysis and a careful study of evolution effects, by exhibiting shadow GPDs with arbitrarily small imprints on DVCS observables at current and future experimental facilities. This shows that DVCS alone will not allow for a model independent extraction of GPDs and a multi-channel analysis is required for this purpose.

• Correlations between azimuthal asymmetries and multiplicity and mean transverse momentum in small collisions systems in the CGC

  Tolga Altinoluk, Néstor Armesto, Alex Kovner, Michael Lublinsky, Vladimir V. Skokov

  SciPost Phys. Proc. 8, 051 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Considering a dilute-dense situation suitable for pA collisions, we compute in the Color Glass Condensate the correlation between azimuthal asymmetries, specifically the squared second Fourier coefficient $v_2^2$, and the total multiplicity in the event. We also analyse the correlation between $v_2^2$ and the mean squared transverse momentum of particles in the event. In both cases, we find that the correlations are generally very small, consistent with the observations. We also note an interesting sharp change in the value of $v_2^2$ and its correlations as a function of the width of the transverse momentum bin, related with a change of the dominance of Bose and HBT quantum correlations.

• WG2 Summary: Small-x, Diffraction and Vector Mesons

  Tolga Altinoluk, Marta Luszczak, Daniel Tapia Takaki

  SciPost Phys. Proc. 8, 110 (2022) · published 13 July 2022 | Toggle abstract · pdf

  Here we briefly summarize the contributions to Working Group 2: Small-x, Diffraction and Vector Mesons, at the DIS2021 Workshop.

• Momentum transfer dependence of heavy quarkonium electroproduction

  Michal Krelina, Jan Nemchik

  SciPost Phys. Proc. 8, 114 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We investigate the momentum transfer dependence of differential cross sections $d\sigma/dt$ in diffractive electroproduction of heavy quarkonia on proton targets. Model predictions for $d\sigma/dt$ within the light-front QCD dipole formalism are based on a realistic model for a proper correlation between the impact parameter $\vec b$ of a collision and color dipole orientation $\vec r$. We demonstrate a significance of $\vec b-\vec r$ correlation by comparing with a standard simplification $\vec{b}\parallel\vec{r}$, frequently used in the literature.

• Anomalous coupling studies with forward protons at the LHC

  C. Royon

  SciPost Phys. Proc. 8, 115 (2022) · published 13 July 2022 | Toggle abstract · pdf

  We describe the gain on sensitivities to quartic $\gamma \gamma \gamma \gamma$, $\gamma \gamma WW$ and $\gamma \gamma \gamma Z$ anomalous couplings and to the search for Axion-Like Particles by two or three orders of magnitude with respect to standard methods at the LHC by tagging intact protons in the final state.