Mon·Sep 12, 2022Monday·September 12, 2022

1. 01*

   MoEDAL-MAPP, an LHC Dedicated Detector Search Facility

   James Pinfold

   During LHC's Run-2 the MoEDAL experiment, the LHC's first dedicated search experiment, took over 6 fb^-1 of data at IP8, with p-p and Pb-Pb collisions, operating with 100% efficiency. The LHCC has endorsed the LoI of the MoEDAL Collaboration describing an exciting program to expand the search for Highly Ionizing Particles (HIPs) in p-p and heavy-ion collisions to include feebly ionizing and Long Lived Particle (LLP) messengers of new physics (NP) at LHC's RUN-3 and eventually HL-LHC. In 2021, as part of Phase-1 of the program, the baseline MoEDAL detector was approved by CERN for reinstallation for Run-3 with increased efficiency, lower threshold, a factor of 5 increase in instantaneous luminosity, and, a higher Ecm. MoEDAL will continue the search for HIP avatars of NP with an emphasis on the search for massive, single and multiply electrically charged avatars of BSM physics arising from, eg, supersymmetry, neutrino mass models, L-R symmetry, etc. As part of Phase-1 of the MoEDAL-MAPP project CERN also approved in 2021 the installation of the MoEDAL Apparatus for Penetrating Particles (MAPP) in the UA83 tunnel 100m away from IP8. The MAPP detector has sensitivity to feebly-interacting particles with charge, or effective charge, as low as 10^-3e. Additionally, the MAPP detector, in conjunction with MoEDAL's trapping detector, gives us a unique sensitivity to charged LLPs. MAPP also has some sensitivity to neutral LLPs. In Phase-2 of the project we will instal the MAPP-2 upgrade for the HL-LHC. We envisage that this detector will be deployed in the UGC1 gallery near to IP8. This phase of the experiment is designed to ensure that MoEDAL-MAPP's sensitivity to neutral LLP messengers of BSM physics is competitive and complementary to other planned projects in this arena. Initial MoEDAL plans for the MEDICI facility at the 100 TeV FCC-hh machine will also be briefly presented.

   hep-phhep-ex49 citations
2. 02*

   Fixed-target charmonium production and pion parton distributions

   Wen-Chen Chang🇹🇼 · Jen-Chieh Peng🇺🇸 · Stephane Platchkov🇫🇷 · Takahiro Sawada🇺🇸

   We investigate how charmonium hadroproduction at fixed-target energies can be used to constrain the gluon distribution in pions. Using nonrelativistic QCD (NRQCD) formulation, the $J/\psi$ and $\psi (2S)$ cross sections as a function of longitudinal momentum fraction $x_F$ from pions and protons colliding with light targets, as well as the $\psi (2S)$ to $J/\psi$ cross section ratios, are included in the analysis. The color-octet long-distance matrix elements are found to have a pronounced dependence on the pion parton distribution functions (PDFs). This study shows that the $x_F$ differential cross sections of pion-induced charmonium production impose strong constraints on the pion's quark and gluon PDFs. In particular, the pion PDFs with larger gluon densities provide a significantly better description of the data. It is also found that the production of the $\psi (2S)$ state is associated with a larger quark-antiquark contribution, compared with $J/\psi$.

   hep-phhep-exnucl-exnucl-thPRD(2023)·11 citations
3. 03*

   Higgs boson in a flavor-extension of the CMSSM

   Surabhi Gupta🇮🇳 · Sudhir Kumar Gupta🇮🇳 · Keven Ren🇦🇺

   Flavour-violating couplings of Higgs boson with stop and scharm quarks could be very important as in addition to lifting the mass of the Higgs boson by a few GeV, it could also play a vital phenomenological role in reducing the Supersymmetry breaking scale significantly. In this work, we investigate effects of such flavour-violating couplings within the Constrained Minimal Supersymmetric Standard Model (CMSSM) framework in the context of LEP data, Higgs data at the LHC, precision observables and the relic density of the dark matter using Bayesian statistics. Our detailed analysis reveals that the most probable values of $m_0$, $m_{1/2}$, $A_0$, $\tan \beta$, ${\delta }_{ct}^{LR}$ are expected to be around 4.83 TeV, 2.54 TeV, 1.90 TeV, 41.5, and 6.1$\times 10^{-2}$, respectively, with flat priors. The corresponding values translate into 3.25 TeV, 2.13 TeV, 1.90 TeV, 44.7, and 5.9$\times 10^{-2}$, respectively, if the natural priors are used. Furthermore, a comparison of our model with the CMSSM of flavour-conservation as the base model yields a Bayes factor of about 6 while taking into account all the experimental constraints used in our study. Our analysis also reflects that the lightest neutralino would have a mass of about 1 TeV.

   hep-phhep-ex0 citations
4. 04*

   The $\mathbf{X}(3872)$'s excitation and its connection with production at hadron colliders

   M.C. Gordillo🇪🇸 · F. De Soto🇪🇸 · J. Segovia🇪🇸

   The LHCb collaboration has found that the production rate of $X(3872)$ in proton-proton collisions decreases as final state particle multiplicity increases. Moreover, the ALICE experiment at CERN has observed that the number of deuterons produced increases with multiplicity, a behavior that is qualitatively different from that of the $X(3872)$. These experimental findings may point to a compact structure for the $X(3872)$ or, at least, that its hadronization could proceed through a charm-anticharm core. We have recently used a diffusion Monte Carlo method to solve the many-body Schrödinger equation that describes the $X(3872)$ as a $c\bar{c}q\bar{q}$ tetraquark system with quantum numbers $I^G(J^{PC})=0^{+}(1^{++})$ and $1^{-}(1^{++})$. According to our structural analysis, the quark--(anti-)quark correlations resemble light-meson--heavy-meson molecules of type $\omega J/\psi$ and $\rho J/\psi$, rather than the most extended $D{\bar{D}}^{\ast }$ interpretation. It was argued that this fact may be the key to make compatible the molecular features of the $X(3872)$ with its production observables. The same formalism allows us to compute the first color excited $c\bar{c}q\bar{q}$ tetraquark state with either $I^G(J^{PC})=0^{+}(1^{++})$ or $1^{-}(1^{++})$. A bound-state is found in each channel, their masses are around 4.0 GeV which is an energy region where many new exotic candidates have been collected by the Particle Data Group. Concerning their structural properties, these states cluster in a compact diquark-antidiquark arrangement which matches perfectly with a so-called Born-Oppenheimer tetraquark configuration. The promptly production rates of these states in proton-proton, proton-nucleus and nucleus-nucleus collisions should fall off equal to or even faster than those of the $X(3872)$.

   hep-phhep-exhep-latnucl-ex+1PRD(2022)·10 citations
5. 05*

   Heavy-flavor meson and baryon production in high-energy nucleus-nucleus collisions

   Andrea Beraudo🇮🇹 · Arturo De Pace🇮🇹 · Daniel Pablos Alfonso🇮🇹 · Francesco Prino🇮🇹 · Marco Monteno🇮🇹 · Marzia Nardi🇮🇹

   We present a new model for the description of heavy-flavor hadronization in relativistic heavy-ion collisions. We explore its effect on the charmed hadron yields and kinematic distributions once the latter is applied at the end of transport calculations used to simulate the propagation of heavy quarks in the deconfined fireball produced in the collision. The model is based on the formation of color-singlet clusters through the recombination of charm quarks with light antiquarks or diquarks from the same fluid cell. This local mechanism of color neutralization leads to a strong space-momentum correlation, which provides a substantial enhancement of charmed baryon production and of the collective flow of all charmed hadrons.

   hep-phnucl-exnucl-thEPJ Web Conf.(2023)·0 citations
6. 06*

   Snowmass 2021 topical group report: Neutrinos from Natural Sources

   Yusuke Koshio🇯🇵 · Gabriel D. Orebi Gann🇺🇸 · Erin O'Sullivan🇸🇪 · Irene Tamborra🇩🇰

   This is the final report from the Snowmass 2021 Neutrino Frontier Topical Group on Neutrinos from Natural Sources. It covers a broad range of neutrino sources, from low-energy neutrinos from the early universe to ultra high-energy sources. We divide this report by source, and discuss the motivations for pursuing searches in each case, the current state of the field, and the prospects for future theoretical and experimental developments. We consider neutrinos produced in the early universe; solar neutrinos; geoneutrinos; supernova neutrinos, including the diffuse supernova neutrino background (DSNB); neutrinos produced in the atmosphere; and high-energy astrophysical neutrinos.

   hep-phastro-ph.HEhep-exhep-th6 citations
7. 07*

   The Recoil Proton Polarization: a new discriminative DVCS observable

   Olga Bessidskaia Bylund (1)🇫🇷 · Maxime Defurne (1)🇫🇷 · Pierre A. M. Guichon (1) ((1) Irfu, CEA, Université Paris-Saclay, 91191, Gif-sur-Yvette, France)🇫🇷

   Generalized parton distributions describe the correlations between the longitudinal momentum and the transverse position of quarks and gluons in a nucleon. They can be constrained by measuring photon leptoproduction observables, arising from the interference between Bethe-Heitler and Deeply virtual Compton scattering processes. At leading-twist/leading-order, the amplitude of the latter is parameterized by complex integrals of the GPDs {H, E, H̃, Ẽ . As data collected on an unpolarized or longitudinally polarized target constrains H and H̃, E is poorly known as it requires data collected with a transversely polarized target, which is very challenging to implement in fixed target experiments. The only alternative considered so far has been DVCS on a neutron with a deuterium target, while assuming isospin symmetry and absence of final-state interactions. Today, we introduce the polarization of the recoil proton as a new DVCS observable, highly sensitive to E, which appears feasible for an experimental study at a high-luminosity facility such as Jefferson Lab.

   hep-phhep-exPRD(2023)·6 citations
8. 08*

   Pursuit of $CP$ violation in hyperon decays at $e^{+}{e}^{-}$ colliders

   Xiao-Gang He🇨🇳 · Jusak Tandean🇮🇩 · German Valencia🇦🇺

   We present a concise overview on $CP$ violation in hyperon decays, including past, present, and future efforts to search for it. We highlight in particular the most recent results of the BESIII experiment using a quantum-entangled pair of hyperon and antihyperon produced by a charmonium resonance formed in $e^{+}{e}^{-}$ annihilation. The subsequent nonleptonic decays of these hyperon pairs allow for the simultaneous determination of various parameters pertaining to $CP$ violation in the decays. We compare the reported data with the corresponding current predictions for $CP$ asymmetries within the standard model of particle physics. Moreover, we touch on how much these asymmetries might be enhanced by possible new physics beyond the standard model. We also comment briefly on the importance of the proposed super tau-charm factories in future quests for hyperon $CP$-violation.

   hep-phhep-ex1 citation
9. 09*

   XQC and CSR constraints on strongly interacting dark matter with spin and velocity dependent cross sections

   Yonglin Li🇨🇳 · Zuowei Liu🇨🇳 · Yilun Xue🇨🇳

   Dark matter that interacts strongly with baryons can avoid the stringent dark matter direct detection constraints, because, like baryons, they are likely to be absorbed when traversing the rocks, leading to a suppressed flux in deep underground labs. Such strongly interacting dark matter, however, can be probed by dark matter experiments or other experiments operated on the ground level or in the atmosphere. In this paper we carry out systematic analysis of two of these experiments, XQC and CSR, to compute the experimental constraints on the strongly interacting dark matter in the following three scenarios: (1) spin-independent and spin-dependent interactions; (2) different velocity dependent cross sections; (3) different dark matter mass fractions. Some of the scenarios are first analyzed in the literature. We find that the XQC exclusion region has some non-trivial dependencies on the various parameters and the limits in the spin-dependent case is quite different from the spin-independent case. A peculiar region in the parameter space, where the XQC constraint disappears, is also found in our Monte Carlo simulations. This occurs in the case where the interaction cross section is proportional to the square of the velocity. We further compare our XQC and CSR limits to other experimental constraints, and find that a large parameter space is allowed by various experiments if the dark matter mass fraction is sufficiently small, $f_{\chi }\lesssim 10^{-4}$.

   hep-phastro-ph.COJCAP(2023)·12 citations
10. 10*

    Leptonic signatures of color-sextet scalars

    Linda M. Carpenter🇺🇸 · Taylor Murphy🇺🇸 · Katherine Schwind🇺🇸

    Color-sextet scalars could have an array of possible couplings to the Standard Model beyond their well known renormalizable couplings to quark pairs. The next-largest couplings these scalars might enjoy have mass dimension six, and some include electroweak fields and can therefore produce highly distinctive signals at hadron colliders. Here we study the single production of color-sextet scalars in association with a hard lepton, which results from a dimension-six coupling to leptons in addition to quarks and gluons. We identify parameter space in which these scalars decay promptly and propose a search for such particles in final states with two jets and an opposite-charge lepton pair, one member of which has high momentum. We then impose our selection criteria on the proposed signal and its leading backgrounds to project the discovery potential and exclusion limits during the next runs of the LHC. We compare our search with existing searches for leptoquarks, and we find we achieve much higher sensitivity with our tailored approach due to the unique kinematics of leptonic sextet events.

    hep-phPRD(2022)·9 citations
11. 11*

    Model-independent analysis of $b\to d$ processes

    Rigo Bause🇩🇪 · Hector Gisbert🇩🇪 · Marcel Golz🇩🇪 · Gudrun Hiller🇩🇪

    We perform a model-independent analysis of $|\Delta b|=|\Delta d|=1$ processes to test the standard model and probe flavor patterns of new physics. Constraints on Wilson coefficients are obtained from global fits to $B^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$, $B_s^0\to {\bar{K}}^{\ast 0}{\mu }^{+}{\mu }^{-}$, $B^0\to {\mu }^{+}{\mu }^{-}$, and radiative $B\to X_d\gamma$ decays data. The fits are consistent with the standard model but leave sizable room for new physics. Besides higher-statistics measurements and more data in theory-friendly bins of the dilepton mass, further complementary observables such as angular distributions of $B_s^0\to {\bar{K}}^{\ast 0}{\ell }^{+}{\ell }^{-}$, $B\to \rho {\ell }^{+}{\ell }^{-}$ or the baryonic modes ${\Xi }_b\to \Sigma {\ell }^{+}{\ell }^{-}$, ${\Omega }_b^{-}\to {\Xi }^{-}{\ell }^{+}{\ell }^{-}$ are necessary to resolve the significant degeneracy in the fit for the semileptonic four-fermion operators. Assuming minimal quark flavor violation, the $b\to s$ global fit implies tight constraints on the $b\to d$ couplings, and hence allows to test this paradigm with improved data. Another benefit from $|\Delta b|=|\Delta d|=1$ processes is to shed light on the $B$-anomalies in $|\Delta b|=|\Delta s|=1$ modes from a new angle. Specifically, studies of lepton flavor-specific and dineutrino modes are informative on the lepton flavor structure. Rare $b\to d\ell \ell ,\nu \bar{\nu }$ decays can be studied at high luminosity flavor facilities LHCb, Belle II, and a future $Z$-factory.

    hep-phhep-exEPJC(2023)·43 citations
12. 12*

    HNL mass degeneracy: implications for low-scale seesaws, LNV at colliders and leptogenesis

    Enrique Fernández-Martínez🇪🇸 · Xabier Marcano🇪🇸 · Daniel Naredo-Tuero🇪🇸

    Low-scale seesaw variants protected by lepton number symmetry provide a natural explanation of the smallness of neutrino masses but, unlike their higher-scale counterparts, with potentially testable phenomenology. The approximate lepton number symmetry arranges the heavy neutrinos in pseudo-Dirac pairs, which might be accessible at collider or even beam dump experiments if their mass is low enough and their mixing with the active neutrinos sufficiently large. Despite their pseudo-Dirac nature, their small mass splittings may lead to oscillations that prevent the cancellation of their potential lepton-number-violating signals. Interestingly, these small splittings may also resonantly enhance the production of a lepton number asymmetry for low-scale leptogenesis scenarios or, for extremely degenerate states, lead to an asymmetry large enough to resonantly produce a keV sterile neutrino dark matter candidate with the correct relic abundance via the Shi-Fuller mechanism. In this work we explore the parameter space of the different low-scale seesaw mechanisms and study the size of these splittings, given their important and interesting phenomenological consequences. While all low-scale seesaw variants share the same dimension 5 and 6 operators when integrating out the heavy states, we point out that the mass splitting of the pseudo-Dirac pairs are very different in different realizations such as the inverse or linear seesaw. This different phenomenology could offer a way to discriminate between low-scale seesaw realizations.

    hep-phhep-exJHEP(2023)·28 citations
13. 13*

    Bound states and electromagnetic radiation of relativistically rotating cylindrical wells

    Matteo Buzzegoli🇺🇸 · Kirill Tuchin🇺🇸

    We compute the effect of rigid rotation on the non-relativistic bound states. The energy levels of the bound states increase with the angular velocity of rotation until at certain value of the angular velocity they are completely pushed out into the continuum which corresponds to dissociation of the bound states. When the angular velocity exceeds the critical value at which the ground state disappears into the continuum, no bound state is possible. This effect should have important consequences for the phenomenology of the quark-gluon plasma. One of the ways to study it experimentally is to observe the electromagnetic radiation emitted by a rotating bound state. We compute the corresponding intensity of electromagnetic radiation and show that it strongly depends on the angular velocity of rotation.

    ↳ nucl-thastro-ph.HEhep-phNPA(2023)·11 citations
14. 14*

    Ultimate Limit of Future Colliders

    M.Bai🇺🇸 · V.Shiltsev🇺🇸 · G. White🇺🇸 · F. Zimmermann🇨🇭

    With seven operational colliders in the world and two under construction, the international particle physics community not only actively explores options for the next facilities for detailed studies of the Higgs/electroweak physics and beyond-the-LHC energy frontier, but also seeks a clear picture of the limits of the colliding beams method. In this paper, we try to consolidate various recent efforts in identifying physics limits of colliders in conjunction with societal sustainability, and share our thoughts about the perspective of reaching the ultimate collider that is at the quantum limit.

    ↳ physics.acc-phhep-phJACoW(2022)·1 citation
15. 15*

    Enhanced pion-to-proton ratio at the onset of the QCD phase transition

    Thiranat Bumnedpan🇹🇭 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪 · Ayut Limphirat🇹🇭 · Christoph Herold🇹🇭

    The pion-to-proton ratio is identified as a potential signal for a non-equilibrium first-order chiral phase transition in heavy-ion collisions, as the pion multiplicity is directly related to entropy production. To showcase this effect, a non-equilibrium Bjorken expansion starting from realistic initial conditions along a Taub adiabat is used to simulate the entropy production. Different dynamical criteria to determine the final entropy-per-baryon number are investigated and matched to a hadron resonance gas model along the chemical freeze out curve to obtain the final pion and proton numbers. We detect a strong enhancement of their multiplicity ratio at the energies where the system experiences a strong phase transition as compared to a smooth crossover which shows almost no enhancement.

    ↳ nucl-thhep-phPLB(2022)·7 citations
16. 16*

    Moments and power corrections of longitudinal and transverse proton structure functions from lattice QCD

    M. Batelaan🇦🇺 · K. U. Can🇦🇺 · A. Hannaford-Gunn🇦🇺 · R. Horsley🇬🇧 · Y. Nakamura🇯🇵 · H. Perlt🇩🇪 · P. E. L. Rakow🇬🇧 · G. Schierholz🇩🇪 · H. Stüben🇩🇪 · R. D. Young🇦🇺 · J. M. Zanotti🇦🇺

    We present a simultaneous extraction of the moments of $F_2$ and $F_L$ structure functions of the proton for a range of photon virtuality, $Q^2$. This is achieved by computing the forward Compton amplitude on the lattice utilizing the second-order Feynman-Hellmann theorem. Our calculations are performed on configurations with two different lattice spacings and volumes, all at the $SU(3)$ symmetric point. We find the moments of $F_2$ and $F_L$ in good agreement with experiment. Power corrections turn out to be significant. This is the first time the $Q^2$ dependence of the lowest moment of $F_2$ has been quantified.

    ↳ hep-lathep-phnucl-thPRD(2023)·14 citations
17. 17*

    Search for relativistic fractionally charged particles in space

    DAMPE Collaboration: F. Alemanno · C. Altomare · Q. An · P. Azzarello · F. C. T. Barbato · P. Bernardini · X. J. Bi · M. S. Cai · E. Casilli · E. Catanzani · J. Chang · D. Y. Chen and 138 other authors

    More than a century after the performance of the oil drop experiment, the possible existence of fractionally charged particles FCP still remains unsettled. The search for FCPs is crucial for some extensions of the Standard Model in particle physics. Most of the previously conducted searches for FCPs in cosmic rays were based on experiments underground or at high altitudes. However, there have been few searches for FCPs in cosmic rays carried out in orbit other than AMS-01 flown by a space shuttle and BESS by a balloon at the top of the atmosphere. In this study, we conduct an FCP search in space based on on-orbit data obtained using the DArk Matter Particle Explorer (DAMPE) satellite over a period of five years. Unlike underground experiments, which require an FCP energy of the order of hundreds of GeV, our FCP search starts at only a few GeV. An upper limit of $6.2\times 10^{-10}\mathrm{c}{\mathrm{m}}^{-2}\mathrm{s}{\mathrm{r}}^{-1}{\mathrm{s}}^{-1}$ is obtained for the flux. Our results demonstrate that DAMPE exhibits higher sensitivity than experiments of similar types by three orders of magnitude that more stringently restricts the conditions for the existence of FCP in primary cosmic rays.

    ↳ astro-ph.HEhep-exhep-phphysics.space-phPRD(2022)·14 citations
18. 18*

    Higgsless simulations of cosmological phase transitions and gravitational waves

    Ryusuke Jinno🇪🇸 · Thomas Konstandin🇩🇪 · Henrique Rubira🇩🇪 · Isak Stomberg🇩🇪

    First-order cosmological phase transitions in the early Universe source sound waves and, subsequently, a background of stochastic gravitational waves. Currently, predictions of these gravitational waves rely heavily on simulations of a Higgs field coupled to the plasma of the early Universe, the former providing the latent heat of the phase transition. Numerically, this is a rather demanding task since several length scales enter the dynamics. From smallest to largest, these are the thickness of the Higgs interface separating the different phases, the shell thickness of the sound waves, and the average bubble size. In this work, we present an approach to perform Higgsless simulations in three dimensions, producing fully nonlinear results, while at the same time removing the hierarchically smallest scale from the lattice. This significantly reduces the complexity of the problem and contributes to making our approach highly efficient. We provide spectra for the produced gravitational waves for various choices of wall velocity and strength of the phase transition, as well as introduce a fitting function for the spectral shape.

    ↳ astro-ph.COhep-phJCAP(2023)·78 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.