Publications

Order by: publication date number of citations

• Particle representation for $NN{\bar K}$ system

  Branislav Vlahovic, Igor Filikhin, Roman Ya. Kezarashvili

  SciPost Phys. Proc. 3, 044 (2020) · published 27 February 2020 | Toggle abstract · pdf

  In the framework of the Faddeev equations in configuration space we perform an analysis of quasi-bound state of the $NN{\bar K}$ system within a particle model. In our approach, the system $NN{\bar K}(s_{NN}=0)$ ($NN{\bar K}(s_{NN}=1))$ is described as a superposition of $ppK^{-}$ and $pn{\bar K}^0$ ($nn{\bar K}^{0}$ and $pn{ K}^-$) states, which is possible due to a particle transition. The relation of the particle model to the theory of a two-state quantum system is addressed and discussed taking into account the possibilities of deep and shallow $NN{\bar K}(s_{NN}=0)$ quasi-bound states.

  3 citations

• Fluctuations of work in realistic equilibrium states of quantum systems with conserved quantities

  Jordi Mur-Petit, Armando Relaño, Rafael A. Molina, Dieter Jaksch

  SciPost Phys. Proc. 3, 024 (2020) · published 25 February 2020 | Toggle abstract · pdf

  The out-of-equilibrium dynamics of quantum systems is one of the most fascinating problems in physics, with outstanding open questions on issues such as relaxation to equilibrium. An area of particular interest concerns few-body systems, where quantum and thermal fluctuations are expected to be especially relevant. In this contribution, we present numerical results demonstrating the impact of conserved quantities (or ‘charges’) in the outcomes of out-of-equilibrium measurements starting from realistic equilibrium states on a few-body system implementing the Dicke model.

  3 citations

• The search for the neutron electric dipole moment at PSI

  Guillaume Pignol, Philipp Schmidt-Wellenburg

  SciPost Phys. Proc. 5, 027 (2021) · published 6 September 2021 | Toggle abstract · pdf

  The existence of a nonzero permanent electric dipole moment (EDM) of the neutron would reveal a new source of CP violation and shed light on the origin of the matter--antimatter asymmetry of the Universe. The sensitivity of current experiments using stored ultracold neutrons (UCN) probes new physics beyond the TeV scale. Using the UCN source at the Paul Scherrer Institut, the nEDM collaboration has performed the most sensitive measurement of the neutron EDM to date, still compatible with zero ($|d_n|<1.8\times 10^{-26} \, e {\rm cm}$, C.L.90%). A new experiment designed to improve the sensitivity by an order of magnitude, n2EDM, is currently in construction.

  3 citations

• PDF4LHC21: Update on the benchmarking of the CT, MSHT and NNPDF global PDF fits

  Thomas Cridge

  SciPost Phys. Proc. 8, 101 (2022) · published 13 July 2022 | Toggle abstract · pdf

  There have been recent updates to the three global PDF fits (CT, MSHT and NNPDF), all adding large amounts of data from the LHC, and this has resulted in significant changes to the global PDFs. Given the impact that the new PDFs will have on physics comparisons at the LHC, it is crucial to perform a benchmarking among the PDFs, similar in spirit to that which was carried out for PDF4LHC15, widely used for LHC physics. In this article we detail a benchmarking comparison of three global PDF sets - CT18, MSHT20 and NNPDF3.1 - and their similarities and differences that have been observed. The end result of this study will be a new PDF4LHC21 ensemble of combined PDFs suitable for a wide range of LHC applications.

  3 citations

• Impact parameter dependence of color charge correlations in the proton

  Adrian Dumitru, Heikki Mäntysaari, Risto Paatelainen

  SciPost Phys. Proc. 8, 058 (2022) · published 12 July 2022 | Toggle abstract · pdf

  The impact parameter dependence of color charge correlators in the proton is obtained from the light front formalism in light cone gauge. We include NLO corrections due to the $|qqqg\rangle$ Fock state via light-cone perturbation theory. Near the center of the proton, the $b$-dependence of the correlations is very different from a "transverse profile function". The resulting $t$-dependence of exclusive $J/\Psi$ photoproduction transitions from exponential to power law at $|t| \approx 1$ GeV$^2$. This prediction could be tested at upcoming DIS facilities or in nucleus-proton ultraperipheral collisions (UPCs).

  2 citations

• Twist-3 partonic distributions from lattice QCD

  Shohini Bhattacharya, Krzysztof Cichy, Martha Constantinou, Andreas Metz, Aurora Scapellato, Fernanda Steffens

  SciPost Phys. Proc. 8, 057 (2022) · published 12 July 2022 | Toggle abstract · pdf

  Twist-3 partonic distributions contain important information that characterizes nucleon's structure. In this work, we show our lattice exploration of the twist-3 PDFs $g_T(x)$, and $h_L(x)$. We also present our preliminary results on the twist-3 GPD $\tilde{G}_2(x)$. We use the quasi-distribution approach to connect the lattice-extracted matrix elements, renormalized in the RI/MOM scheme, to light-cone distributions, applying the matching procedure that we developed in parallel. We also calculate the twist-2 counterparts of $g_T(x)$ and $h_L(x)$, i.e. $g_1(x)$, and $h_1(x)$, and test the Wandzura-Wilczek approximation.

  2 citations

• Study of deuteron-proton backward elastic scattering at intermediate energies

  Nadezhda Ladygina

  SciPost Phys. Proc. 3, 053 (2020) · published 27 February 2020 | Toggle abstract · pdf

  We study deuteron- proton elastic scattering in the deuteron energy range between 500 MeV and 2~GeV at the cms scattering angle $\theta^*\ge 140^\circ$. The reaction is considered in the relativistic multiple scattering expansion framework. The four reaction mechanisms are included into consideration: one-nucleon exchange, single scattering, double scattering, and the term corresponding to the delta excitation in the intermediate state. The model is applied to describe the angular dependence of the differential cross section at the deuteron energies of between 880 and 1300 MeV. Also the energy dependence of the differential cross section and polarisation observables such as tensor analyzing power $T_{20}$ and polarization transfer from the deuteron to proton $\varkappa$ are considered at the scattering angle equal to 180$^\circ$. Contributions of the different reaction mechanisms into the reaction amplitude are demonstrated in comparison with the existing experimental data.

  2 citations

• A time-dependent Hartree-Fock study of triple-alpha dynamics

  Paul D. Stevenson, J. L. Willerton

  SciPost Phys. Proc. 3, 047 (2020) · published 27 February 2020 | Toggle abstract · pdf

  Time-dependent Hartree-Fock calculations have been performed for fusion reactions of He-4 + He-4 -> Be*-8, followed by He-4 + Be*-8 . Depending on the orientation of the initial state, a linear chain vibrational state or a triangular vibration is found in 12C, with transitions between these states observed. The vibrations of the linear chain state and the triangular state occur at ~9 and 4 MeV respectively.

  2 citations

• Measurement of Intermittency for Charged Particles in Au + Au Collisions at $\sqrt{s_\mathrm{NN}}$ = 7.7-200 GeV from STAR

  Jin Wu

  SciPost Phys. Proc. 10, 041 (2022) · published 11 August 2022 | Toggle abstract · pdf

  Local density fluctuations near the QCD critical point can be probed by intermittency analysis of scaled factorial moments in relativistic heavy-ion collisions. We report the first measurement of intermittency for charged particles in Au + Au collisions at $\sqrt{s_\mathrm{NN}}$ = 7.7-200 GeV from the STAR experiment at RHIC. We observe scaling behaviors in central Au + Au collisions, with the extracted scaling exponent decreasing from mid-central to the most central Au + Au collisions. Furthermore, the scaling exponent exhibits a non-monotonic energy dependence with a minimum around $\sqrt{s_\mathrm{NN}}$ = 20-30 GeV in central Au + Au collisions.

  2 citations

• Searches for invisible scalar decays at CLIC

  Krzysztof Mekala, Aleksander Filip Zarnecki, Bohdan Grzadkowski, Michal Iglicki

  SciPost Phys. Proc. 8, 091 (2022) · published 13 July 2022 | Toggle abstract · pdf

  The Compact Linear Collider (CLIC) is a proposed TeV-scale high-luminosity electron-positron collider at CERN. The first CLIC running stage, at 380 GeV, will focus on precision Higgs boson and top quark studies while the main aim of the subsequent high-energy stages, at 1.5 TeV and 3 TeV, is to extend the sensitivity of CLIC to different Beyond the Standard Model (BSM) scenarios. We studied the prospects for measuring invisible Higgs boson and additional heavy scalar decays using CLIC data at 380 GeV and 1.5 TeV. The analysis is based on the WHIZARD event generator, with fast simulation of the CLIC detector response parametrised by the DELPHES package. We present the expected limits for the invisible decays of the 125 GeV Higgs boson, the cross section limits for production of an additional neutral Higgs scalar, assuming its invisible decays, and limits on the mixing angle between the SM-like Higgs boson and the new scalar of the "dark sector" in the framework of the vector-fermion dark matter model.

  2 citations