Publications

Order by: publication date number of citations

• A measurement of the proton plus helium spectrum of cosmic rays in the TeV region with HAWC

  Juan Carlos Arteaga-Velázquez on behalf of the HAWC collaboration

  SciPost Phys. Proc. 13, 015 (2023) · published 28 September 2023 | Toggle abstract · pdf

  HAWC is an air-shower detector designed to study TeV gamma and cosmic rays. The observatory is composed of a 22000 $m^2$ array of 300 water Cherenkov tanks (4.5 m deep x 7.3 m diameter) with 4 photomultipliers (PMT) each. The instrument registers the number of hit PMTs, the timing information and the total charge at the PMTs during the event. From these data, shower observables such as the arrival direction, the core position at ground, the lateral age and the primary energy are estimated. In this work, we study the distribution of the shower age vs the primary energy of a sample of shower data collected by HAWC from June 2015 to June 2019 and employ a shower-age cut based on predictions of QGSJET-II-04 to separate a subsample of events dominated by H and He primaries. Using these data and a dedicated analysis, we reconstruct the cosmic ray spectrum of H+He from 6 to 158 TeV, which shows the presence of a softening at around 24 TeV with a statistical significance of 4.1$\sigma$.

• Sivers asymmetry in inelastic $J/ψ$ leptoproduction at the EIC

  Sangem Rajesh, Umberto D'Alesio, Asmita Mukherjee, Francesco Murgia, Cristian Pisano

  SciPost Phys. Proc. 8, 017 (2022) · published 11 July 2022 | Toggle abstract · pdf

  We study the Sivers asymmetry in inelastic $J/\psi$ leptoproduction, $ep^\uparrow \to e+ J/\psi+X$, within a transverse momentum dependent scheme, the so-called generalized parton model (GPM). The effects of final-state interactions are properly taken into account by employing the color-gauge invariant GPM (CGI-GPM). For the $J/\psi$ formation the non-relativistic QCD (NRQCD) framework is adopted. Predictions for unpolarized cross sections and maximized Sivers asymmetries at EIC energies are given.

• Computation of entanglement entropy in inhomogeneous free fermions chains by algebraic Bethe ansatz

  Pierre-Antoine Bernard, Gauvain Carcone, Nicolas Crampé, Luc Vinet

  SciPost Phys. Proc. 14, 018 (2023) · published 23 November 2023 | Toggle abstract · pdf

  The computation of the entanglement entropy for inhomogeneous free fermions chains based on $q$-Racah polynomials is considered. The eigenvalues of the truncated correlation matrix are obtained from the diagonalization of the associated Heun operator via the algebraic Bethe Ansatz. In the special case of chains based on dual $q$-Hahn polynomials, the eigenvectors and eigenvalues are expressed in terms of symmetric polynomials evaluated on the Bethe roots.

• Candidate phases for SU(2) adjoint QCD$_4$ with two flavors from $\mathcal{N}=2$ supersymmetric Yang-Mills theory

  Clay Córdova, Thomas T. Dumitrescu

  SciPost Phys. 16, 139 (2024) · published 29 May 2024 | Toggle abstract · pdf

  We study four-dimensional adjoint QCD with gauge group $SU(2)$ and two Weyl fermion flavors, which has an $SU(2)_R$ chiral symmetry. The infrared behavior of this theory is not firmly established. We explore candidate infrared phases by embedding adjoint QCD into ${\mathcal N}=2$ supersymmetric Yang-Mills theory deformed by a supersymmetry-breaking scalar mass $M$ that preserves all global symmetries and 't Hooft anomalies. This includes 't Hooft anomalies that are only visible when the theory is placed on manifolds that do not admit a spin structure. The consistency of this procedure is guaranteed by a nonabelian spin-charge relation involving the $SU(2)_R$ symmetry that is familiar from topologically twisted ${\mathcal N}=2$ theories. Since every vacuum on the Coulomb branch of the ${\mathcal N}=2$ theory necessarily matches all 't Hooft anomalies, we can generate candidate phases for adjoint QCD by deforming the theories in these vacua while preserving all symmetries and 't Hooft anomalies. One such deformation is the supersymmetry-breaking scalar mass $M$ itself, which can be reliably analyzed when $M$ is small. In this regime it gives rise to an exotic Coulomb phase without chiral symmetry breaking. By contrast, the theory near the monopole and dyon points can be deformed to realize a candidate phase with monopole-induced confinement and chiral symmetry breaking. The low-energy theory consists of two copies of a $\mathbb{CP}^1$ sigma model, which we analyze in detail. Certain topological couplings that are likely to be present in this $\mathbb{CP}^1$ model turn the confining solitonic string of the model into a topological insulator. We also examine the behavior of various candidate phases under fermion mass deformations. We speculate on the possible large-$M$ behavior of the deformed ${\mathcal N}=2$ theory and conjecture that the $\mathbb{CP}^1$ phase eventually becomes dominant.

• Λ(1520) resonance production with respect to transverse spherocity using EPOS3+UrQMD

  Nasir Mehdi Malik, Sanjeev Singh Sambyal

  SciPost Phys. Proc. 15, 027 (2024) · published 3 April 2024 | Toggle abstract · pdf

  Resonances are sensitive to the properties of the medium created in heavy ion collision. They also provide insight into the properties of the hadronic phase. Studying the dependence of the yield of resonances on transverse spherocity and multiplicity allows us to understand the resonance production mechanism with event topology and system size, respectively. The results reported pertain to $\Lambda(1520)$, using predictions from EPOS3+UrQMD event generator.

• Quantum collider probes of the fermionic Higgs portal

  Ulrich Haisch, Maximilian Ruhdorfer, Konstantin Schmid, Andreas Weiler

  SciPost Phys. 16, 112 (2024) · published 25 April 2024 | Toggle abstract · pdf

  We explore the sensitivity of future hadron colliders to constrain the fermionic Higgs portal, with a focus on scenarios where the new fermions cannot be directly observed in exotic Higgs decays. This portal emerges in various models including twin-Higgs scenarios and dark matter models, posing significant challenges for collider tests. Working in an effective field theory (EFT), we determine the reach of the high-luminosity option of the Large Hadron Collider (HL-LHC), the high-energy upgrade of the LHC (HE-LHC) and a proposed Future Circular Collider (FCC) in probing the fermionic Higgs portal through off-shell and double-Higgs production. Notably, we find that quantum-enhanced indirect probes offer a better sensitivity than other direct Higgs measurements. We argue that this finding is valid in a wide class of ultraviolet realisations of the EFT. Our study presents a roadmap of a multifaceted search strategy for exploring the fermionic Higgs portal at forthcoming hadron machines.

• Probing quantum entanglement and collectivity effects in e+p collisions at HERA H1

  Chuan Sun

  SciPost Phys. Proc. 8, 147 (2022) · published 14 July 2022 | Toggle abstract · pdf

  Charged particle multiplicity spectra are measured at HERA H1 in DIS process at 319 GeV. The hadron entropy determined from the multiplicity spectra is compared to the gluon entropy predicted from a quantum-entanglement model. On the other hand, observed collective behaviours in high multiplicity pA, pp and ultra-peripheral PbPb collisions at RHIC and LHC motivate a study in ep collisions. Two- and multi-particle correlations are studied in DIS, as well as photoproduction events with collision energy <Wγp>~270 GeV.

• Disordered $\mathcal{N} = (2, 2)$ supersymmetric field theories

  Chi-Ming Chang, Xiaoyang Shen

  SciPost Phys. 16, 140 (2024) · published 30 May 2024 | Toggle abstract · pdf

  We investigate a large class of $\mathcal{N}=(2,2)$ supersymmetric field theories in two dimensions, which contains the Murugan-Stanford-Witten model, and can be naturally regarded as a disordered generalization of the two-dimensional Landau-Ginzburg models. We analyze the two and four-point functions of chiral superfields, and extract from them the central charge, the operator spectrum, and the chaos exponent in these models. Some of the models exhibit a conformal manifold parameterized by the variances of the random couplings. We compute the Zamolodchikov metrics on the conformal manifold, and demonstrate that the chaos exponent varies nontrivally along the conformal manifolds. Finally, we introduce and perform some preliminary analysis of a disordered generalization of the gauged linear sigma models, and discuss the low energy theories as ensemble averages of Calabi-Yau sigma models over complex structure moduli space.

• Studies of $b$-hadrons and quarkonia at LHCb

  Zhiyu Xiang

  SciPost Phys. Proc. 8, 092 (2022) · published 13 July 2022 | Toggle abstract · pdf

  LHCb has productive studies of quarkonia and $b$-hadrons which provide essential inputs to study quantum chromodynamics (QCD). In this proceeding, seven recent results are reported: the observation of a new excited $\Xi_b^0$ resonance in $\Xi_b^- \pi^+$ final states, the new excited $B_s^0$ state is observed in $B^+ K^-$ mass spectrum, the first observation of suppressed semileptonic $B_s^0 \rightarrow K^- \mu^+ \nu_{\mu}$ decay, the first observation of the decay $B^0 \rightarrow D^0 \bar{D}^0 K^+ \pi^-$, the first observation of the Cabibbo-suppressed decay $\Lambda_b^0 \rightarrow \chi_{c1} p \pi^-$, the first observation of $\Lambda_b^0 \rightarrow \Lambda_c^+ K^+ K^- \pi^-$ decay, and end this report with the first search for the doubly heavy baryon $\Omega_{bc}^{0}$ and a search for $\Xi_{bc}^0$ baryon.

• Pionic hydrogen and deuterium

  D. Gotta, L. M. Simons

  SciPost Phys. Proc. 5, 014 (2021) · published 6 September 2021 | Toggle abstract · pdf

  The measurement of strong-interaction shift and broadening in pionic hydrogen and deuterium yields pion-nucleon scattering lengths as well as the threshold pion-production strength on isoscalar NN pairs. Results from recent high-resolution experiments at PSI using crystal spectrometers allow important comparisons with the outcome of the modern low-energy description of QCD within the framework of effective field theories.