Publications

Order by: publication date number of citations

• Implications of tau data for CP violation in K decays

  Antonio Rodríguez-Sánchez

  SciPost Phys. Proc. 1, 005 (2019) · published 18 February 2019 | Toggle abstract · pdf

  The $D=6$ contribution of the Operator Product Expansion (OPE) of the VV-AA correlator of quark currents can be related to hadronic matrix elements associated to CP violation in non-leptonic kaon decays. We use those relations to find an updated value for $\langle(\pi\pi)_{I=2}|\mathcal{Q}_{8}|K\rangle$ in the chiral limit using the updated ALEPH spectral function. Taking instead values of the matrix elements from the lattice to obtain the $D=6$ vacuum elements provides a new short-distance constraint that allows for an inclusive determination of $f_{\pi}$ and an updated value for the $D=8$ condensate.

• $tW$ and $tZ'$ production at hadron colliders

  Nikolaos Kidonakis, Marco Guzzi, Nodoka Yamanaka

  SciPost Phys. Proc. 8, 064 (2022) · published 12 July 2022 | Toggle abstract · pdf

  We present theoretical results with soft-gluon corrections for two separate processes: (1) the production of a single top quark in association with a $W$ boson in the Standard Model; and (2) the production of a single top quark in association with a heavy $Z'$ boson in new physics models with or without anomalous couplings. We show that the higher-order corrections from soft-gluon emission are dominant for a wide range of collider energies. Results are shown for the total cross sections and top-quark transverse-momentum and rapidity distributions for $tW$ and $tZ'$ production at LHC and future collider energies up to 100 TeV. The uncertainties from scale dependence and parton distribution functions are also analyzed.

• New 2- and 3-loop heavy flavor corrections to unpolarized and polarized deep-inelastic scattering

  Jakob Ablinger, Johannes Blümlein, Abilio De Freitas, Marco Saragnese, Carsten Schneider, Kay Schoenwald

  SciPost Phys. Proc. 8, 137 (2022) · published 14 July 2022 | Toggle abstract · pdf

  A survey is given on the new 2– and 3–loop results for the heavy flavor contributions to deep–inelastic scattering in the unpolarized and the polarized case. We also discuss related new mathematical aspects applied in these calculations.

• 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.

• Inclusive and diffractive dijet photoproduction in ultraperipheral heavy ion collisions at the LHC

  V. Guzey, M. Klasen

  SciPost Phys. Proc. 8, 141 (2022) · published 14 July 2022 | Toggle abstract · pdf

  We calculate the cross section of inclusive dijet photoproduction in ultraperipheral collisions (UPCs) of heavy ions at the CERN Large Hadron Collider using next-to-leading order perturbative QCD and demonstrate that it provides a good description of the ATLAS data. We study the role of this data in constraining nuclear parton distribution functions (nPDFs) using the Bayesian reweighting technique and find that it can reduce current uncertainties of nPDFs at small $x$ by a factor of 2. We also make predictions for diffractive dijet photoproduction in UPCs and examine its potential to shed light on the disputed mechanism of QCD factorization breaking in diffraction.

• Prospects for diffractive dijet photoproduction at the EIC

  V. Guzey, M. Klasen

  SciPost Phys. Proc. 8, 142 (2022) · published 14 July 2022 | Toggle abstract · pdf

  We discuss the prospects of diffractive dijet photoproduction at the EIC to distinguish different fits of diffractive proton PDFs, different schemes of factorization breaking, to determine diffractive nuclear PDFs and pion PDFs from leading neutron production.

• 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.

• Photoproduction of diffractive dijets in Pythia 8

  Ilkka Helenius

  SciPost Phys. Proc. 8, 145 (2022) · published 14 July 2022 | Toggle abstract · pdf

  The new framework for the simulations of hard diffractive events in photoproduction within Pythia 8 is presented. The model, originally introduced for proton-proton collisions, applies the dynamical rapidity gap survival probability based on the multiparton interaction model in Pythia. These additional interactions provide a natural explanation for the observed factorization-breaking effects in hard diffraction by filling up the rapidity gaps used to classify the events of diffractive origin. The generated cross sections are well in line with the existing data from HERA experiments and predictions for the future electron-ion collider are presented. In addition, also predictions for ultra-peripheral collisions at the LHC have been calculated where the factorization-breaking effects are found to be more pronounced.

• 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.

• Exclusive electro-weak production of a charmed meson at high energy

  B. Pire, L. Szymanowski, J. Wagner

  SciPost Phys. Proc. 8, 150 (2022) · published 14 July 2022 | Toggle abstract · pdf

  Exclusive electro-weak processes have peculiar features which make them complementary to usually discussed deeply virtual electroproduction processes such as deep virtual Compton scattering or meson production (and the corresponding crossed reactions). They allow in particular single charmed meson production, which we study in two different contexts : electroproduction at an electron ion collider and neutrino-production at a medium energy neutrino facility. We rely on the QCD collinear factorization framework where generalized parton distributions allow physicists to perform a nucleon tomography.