Mon·Jun 21, 2021Monday·June 21, 2021

1. 01*

   Gravitational Waves from Global Cosmic Strings and Cosmic Archaeology

   Chia-Feng Chang🇺🇸 · Yanou Cui🇺🇸

   Global cosmic strings are predicted in many motivated extensions to the Standard Model of particle physics, with close connections to axion dark matter physics. Recent studies suggest that, although subdominant relative to Goldstone emission, gravitational wave (GW) signals from global strings can be detectable with current and planned GW detectors such as LIGO, LISA, DECIGO/BBO, ET/CE and AEDGE/AION, as well as pulsar timing arrays such as PPTA, NANOGrav and SKA. This work is an extensive, updated study on GWs from a global cosmic string network, taking into account of the most recent developments related to the subject. The main analysis is based on the analytical Velocity-dependent One-Scale (VOS) model calibrated with recent simulation results, which provides a generic protocol for such calculations with details given. We also demonstrate how the GW signal can be influenced with variations to the baseline model: this includes considering the uncertainties of model parameters and the potential deviation from the conventional VOS model prediction (i.e. the scaling behavior) as suggested by some of the recent simulation results. Furthermore, we investigated in detail the effect of a non-standard cosmology (e.g. early matter domination or kination) or new particle species on the GW signals from global strings. We demonstrate that the frequency spectrum of GW background from global cosmic strings can be used to probe the cosmic history prior to the Big Bang nucleosynthesis (BBN) (i.e. the primordial dark age) up to a temperature of $T\sim 10^8$ GeV.

   hep-phastro-ph.COgr-qchep-thJHEP(2022)·107 citations
2. 02*

   TMD parton densities and corresponding parton showers: the advantage of four- and five-flavour schemes

   H. Jung🇩🇪 · S. Taheri Monfared🇩🇪

   The calculations of $Z+b\bar{b}$ tagged jet production performed in the four- and five-flavour schemes allow for detailed comparison of the heavy flavour structure of collinear and transverse momentum dependent (TMD) parton distributions as well as for detailed investigations of heavy quarks radiated during the initial state parton shower cascade. We have determined the first set of collinear and TMD parton distributions in the four-flavour scheme with NLO DGLAP splitting functions within the Parton-Branching (PB) approach. The four- and five-flavour PB-TMD distributions were used to calculate $Z+b\bar{b}$ tagged jet production at LHC energies and very good agreement with measurements obtained at $\sqrt{s}=8,13$ TeV by the CMS and ATLAS collaborations is observed. The different configurations of the hard process in the four- and five-flavour schemes allow for a detailed investigation of the performance of heavy flavor collinear and TMD parton distributions and the corresponding initial TMD parton shower, giving confidence in the evolution of the PB-TMD parton densities as well as in the PB-TMD parton shower.

   hep-ph7 citations
3. 03*

   A Supersymmetric Flavor Clockwork

   Wolfgang Altmannshofer🇺🇸 · Sri Aditya Gadam🇺🇸

   Clockwork models can explain the flavor hierarchies in the Standard Model quark and lepton spectrum. We construct supersymmetric versions of such flavor clockwork models. The zero modes of the clockwork are identified with the fermions and sfermions of the Minimal Supersymmetric Standard Model. In addition to generating a hierarchical fermion spectrum, the clockwork also predicts a specific flavor structure for the soft SUSY breaking sfermion masses. We find sizeable flavor mixing among first and second generation squarks. Constraints from Kaon oscillations require the masses of either squarks or gluinos to be above a scale of $\sim 3$ PeV.

   hep-phPRD(2021)·6 citations
4. 04*

   The study of doubly charmed pentaquark $cc\bar{q}qq$ with the SU(3) symmetry

   Ye Xing🇨🇳 · Yuekun Niu🇨🇳

   We study the masses and lifetimes of doubly charmed pentaquark $P_{cc\bar{q}qq}(q=u,d,s)$ primarily. The operation of masses carried out by the doubly heavy triquark-diquark model, whose results suggests the existence of stable states $cc\bar{s}ud$ with the parity $J^P={\frac{1}{2}}^{-}$. The roughly calculation about lifetimes show the short magnitudes, $(4.65_{-0.55}^{+0.71})\times 10^{-13}s$ for the parity $J^P={\frac{1}{2}}^{-}$ and $(0.93_{-0.11}^{+0.14})\times 10^{-12}s$ for $J^P={\frac{3}{2}}^{-}$. Since the pentaquark $cc\bar{s}ud$ is interpreted as the stable bound states against strong decays, then we will focus on the production and possible decay channels of the pentaquark in the next step, the study would be fairly valuable supports for future experiments. For completeness, we systematically studied the production from ${\Omega }_{ccc}$ and the decay modes in the framework SU(3) flavor symmetry, including the processes of semi-leptonic and two body non-leptonic decays. Synthetically, we make a collection of the golden channels.

   hep-phEPJC(2021)·23 citations
5. 05*

   Pion electromagnetic form factor with Minkowskian dynamics

   Emanuel Ydrefors🇧🇷 · Wayne de Paula🇧🇷 · Jorge H Alvarenga Nogueira🇧🇷 · Tobias Frederico🇧🇷 · Giovanni Salmé🇮🇹

   The pion electromagnetic form factor has been calculated for the first time from the solutions of the Bethe-Salpeter equation, obtained directly in Minkowski space by using the Nakanishi integral representation of the Bethe-Salpeter amplitude. The one-gluon exchange kernel contains as inputs the quark and gluon masses, as well as a scale parameter featuring the extended quark-gluon vertex. The range of variability of these parameters is suggested by lattice calculations. After presenting a very successful comparison with the existing data in the whole range of the momentum transfer, we show how inserting the light-front (LF) formalism in our approach allows to achieve further interesting results, like the evaluation of the LF valence form factor and a first investigation of the end-points effects.

   hep-phPLB(2021)·26 citations
6. 06*

   $SU(5)\times U(1{)}_X$ Axion Model with Observable Proton Decay

   Nobuchika Okada🇺🇸 · Digesh Raut🇺🇸 · Qaisar Shafi🇺🇸

   We propose a $SU(5)\times U(1{)}_X\times U(1{)}_{PQ}$ model, where $U(1{)}_X$ is the generalization of the $B-L$ (baryon minus lepton number) gauge symmetry and $U(1{)}_{PQ}$ is the global Peccei-Quinn (PQ) symmetry. There are four fermions families in $\overline{5}+10$ representations of $SU(5)$, a mirror family in $5+\overline{10}$ representations, and three $SU(5)$ singlet Majorana fermions. The $U(1{)}_X$ related anomalies all cancel in the presence of the Majorana neutrinos. The $SU(5)$ symmetry is broken at $M_{GUT}\simeq (6-9)\times 10^{15}$ GeV and the proton lifetime ${\tau }_p$ is estimated to be well within the expected sensitivity of the future Hyper-Kamiokande experiment, ${\tau }_p\lesssim 1.3\times 10^{35}$ years. The $SU(5)$ breaking also triggers the breaking of the PQ symmetry, resulting in axion dark matter (DM), with the axion decay constant $f_a$ of order $M_{GUT}$ or somewhat larger. The CASPEr experiment can search for such an axion DM candidate. The Hubble parameter during inflation must be low, $H_{inf}\lesssim 10^9$ GeV, in order to successfully resolve the axion domain wall, axion DM isocurvature and $SU(5)$ monopole problems. With the identification of the $U(1{)}_X$ breaking Higgs field with the inflaton field, we implement inflection-point inflation, which is capable of realizing the desired value for $H_{inf}$. The vectorlike fermions in the model are essential for achieving successful unification of the SM gauge couplings as well as the phenomenological viability of both axion DM and inflation scenario.

   hep-phPRD(2021)·1 citation
7. 07*

   Study of some local and global $U(1)$ axial condensates in QCD at finite temperature

   Nicoletta Carabba🇱🇺 · Enrico Meggiolaro🇮🇹

   The aim of this work is to study some possible local and global $U(1)$ axial condensates in the high-temperature chirally restored phase of QCD, by means of two nonperturbative analytical techniques: (i) by expressing the functional averages in terms of the spectral density of the Euclidean Dirac operator and (ii) by evaluating the functional integrals in the instanton-background approximation. In this way, besides proving that these condensates are indeed different from zero in the high-temperature regime, we shall also derive their asymptotic temperature dependence and compare it with that of the topological susceptibility.

   hep-phhep-lathep-thPRD(2022)·7 citations
8. 08*

   Rare and Different: Anomaly Scores from a combination of likelihood and out-of-distribution models to detect new physics at the LHC

   Sascha Caron🇳🇱 · Luc Hendriks🇳🇱 · Rob Verheyen🇬🇧

   We propose a new method to define anomaly scores and apply this to particle physics collider events. Anomalies can be either rare, meaning that these events are a minority in the normal dataset, or different, meaning they have values that are not inside the dataset. We quantify these two properties using an ensemble of One-Class Deep Support Vector Data Description models, which quantifies differentness, and an autoregressive flow model, which quantifies rareness. These two parameters are then combined into a single anomaly score using different combination algorithms. We train the models using a dataset containing only simulated collisions from the Standard Model of particle physics and test it using various hypothetical signals in four different channels and a secret dataset where the signals are unknown to us. The anomaly detection method described here has been evaluated in a summary paper [1] where it performed very well compared to a large number of other methods. The method is simple to implement and is applicable to other datasets in other fields as well.

   hep-phSciPost Phys.(2022)·47 citations
9. 09*

   The one-loop tadpole in the geoSMEFT

   T. Corbett🇩🇰

   Making use of the geometric formulation of the Standard Model Effective Field Theory we calculate the one-loop tadpole diagrams to all orders in the Standard Model Effective Field Theory power counting. This work represents the first calculation of a one-loop amplitude beyond leading order in the Standard Model Effective Field Theory, and discusses the potential to extend this methodology to perform similar calculations of observables in the near future.

   hep-phhep-thSciPost Phys.(2021)·14 citations
10. 10*

    An investigation of the ${\alpha }_S$ and heavy quark mass dependence in the MSHT20 global PDF analysis

    T. Cridge🇬🇧 · L.A. Harland-Lang🇬🇧 · A.D. Martin🇬🇧 · R.S. Thorne🇬🇧

    We investigate the MSHT20 global PDF sets, demonstrating the effects of varying the strong coupling ${\alpha }_S(M_Z^2)$ and the masses of the charm and bottom quarks. We determine the preferred value, and accompanying uncertainties, when we allow ${\alpha }_S(M_Z^2)$ to be a free parameter in the MSHT20 global analyses of deep-inelastic and related hard scattering data, at both NLO and NNLO in QCD perturbation theory. We also study the constraints on ${\alpha }_S(M_Z^2)$ which come from the individual data sets in the global fit by repeating the NNLO and NLO global analyses at various fixed values of ${\alpha }_S(M_Z^2)$, spanning the range ${\alpha }_S(M_Z^2)=0.108$ to $0.130$ in units of $0.001$. We make all resulting PDFs sets available. We find that the best fit values are ${\alpha }_S(M_Z^2)=0.1203\pm 0.0015$ and $0.1174\pm 0.0013$ at NLO and NNLO respectively. We investigate the relationship between the variations in ${\alpha }_S(M_Z^2)$ and the uncertainties on the PDFs, and illustrate this by calculating the cross sections for key processes at the LHC. We also perform fits where we allow the heavy quark masses $m_c$ and $m_b$ to vary away from their default values and make PDF sets available in steps of $\Delta m_c=0.05\mathrm{GeV}$ and $\Delta m_b=0.25\mathrm{GeV}$, using the pole mass definition of the quark masses. As for varying ${\alpha }_S(M_Z^2)$ values, we present the variation in the PDFs and in the predictions. We examine the comparison to data, particularly the HERA data on charm and bottom cross sections and note that our default values are very largely compatible with best fits to data. We provide PDF sets with 3 and 4 active quark flavours, as well as the standard value of 5 flavours.

    hep-phEPJC(2021)·52 citations
11. 11*

    Constraining off-shell production of axion-like particles with $Z\gamma$ and $WW$ differential cross-section measurements

    Sonia Carra🇩🇪 · Vincent Goumarre🇩🇪 · Ruchi Gupta🇩🇪 · Sarah Heim🇩🇪 · Beate Heinemann🇩🇪 · Jan Kuechler🇩🇪 · Federico Meloni🇩🇪 · Pablo Quilez🇩🇪 · Yee-Chinn Yap🇩🇪

    This article describes a search for low-mass axion-like particles (ALPs) at the Large Hadron Collider (LHC). If ALPs were produced at the LHC via gluon-gluon fusion and decayed to bosons, the energy dependence of the measured diboson cross-sections would differ from the Standard Model expectation. Measurements of $WW$ and $Z\gamma$ differential cross-sections by the ATLAS collaboration are interpreted to constrain ALP couplings to $W$-, $Z$-bosons and photons assuming gluon-gluon-fusion production.

    ↳ hep-exhep-phPRD(2021)·37 citations
12. 12*

    Study of neutrino-nucleus reactions with CRISP Program (0 < $E_{\nu }$ < 3 GeV)

    R. Perez🇧🇷 · A. Deppman🇧🇷 · Evandro Andrade-II🇧🇷 · A.R. Samana🇧🇷 · F.G. Velasco🇲🇽 · F. Guzmán🇨🇺

    The neutrino-nucleus reactions are studied at energies from 0 to 3 GeV, using the CRISP program. To simulate these reactions, CRISP uses the Monte Carlo method through an intranuclear cascade model. Quase-elastic and baryonic resonance formation channels for the neutrino-nucleon interaction are considered. The total and differential particle emission cross-sections were obtained, obtaining a good agreement with the values reported by the MiniBooNE experiment. The influence of nuclear effects on the studied reactions, such as fermionic motion, the Pauli blocking mechanism, and the nucleonic separation energy, was shown. It was not possible to simultaneously reproduce the ${\nu }_{\mu }+D$ and ${\nu }_{\mu }{+}^{12}C$ reactions using the same axial mass value. For the charged current quasi-elastic channel, $M_A=0.95GeV$ for the ${\nu }_{\mu }+D$ reaction, and $M_A=1.35GeV$ for the ${\nu }_{\mu }{+}^{12}C$ reaction. This can be solved if one considers, in addition to the neutrino-nucleon interaction, the neutrino interaction with a pair of nucleons, just as we demonstrate in the last part of this work.

    ↳ nucl-thhep-phPRD(2022)·2 citations
13. 13*

    MadFlow: automating Monte Carlo simulation on GPU for particle physics processes

    Stefano Carrazza🇮🇹 · Juan Cruz-Martinez🇮🇹 · Marco Rossi🇮🇹 · Marco Zaro🇮🇹

    We present MadFlow, a first general multi-purpose framework for Monte Carlo (MC) event simulation of particle physics processes designed to take full advantage of hardware accelerators, in particular, graphics processing units (GPUs). The automation process of generating all the required components for MC simulation of a generic physics process and its deployment on hardware accelerator is still a big challenge nowadays. In order to solve this challenge, we design a workflow and code library which provides to the user the possibility to simulate custom processes through the MadGraph5_aMC@NLO framework and a plugin for the generation and exporting of specialized code in a GPU-like format. The exported code includes analytic expressions for matrix elements and phase space. The simulation is performed using the VegasFlow and PDFFlow libraries which deploy automatically the full simulation on systems with different hardware acceleration capabilities, such as multi-threading CPU, single-GPU and multi-GPU setups. The package also provides an asynchronous unweighted events procedure to store simulation results. Crucially, although only Leading Order is automatized, the library provides all ingredients necessary to build full complex Monte Carlo simulators in a modern, extensible and maintainable way. We show simulation results at leading-order for multiple processes on different hardware configurations.

    ↳ physics.comp-phhep-exhep-phhep-thEPJC(2021)·31 citations
14. 14*

    Demonstration of Confinement and Chiral Symmetry Breaking in $SO(N_c)$ Gauge Theories

    Csaba Csáki🇺🇸 · Andrew Gomes🇺🇸 · Hitoshi Murayama🇺🇸 · Ofri Telem🇺🇸

    We demonstrate that $SO(N_c)$ gauge theories with matter fields in the vector representation confine due to monopole condensation and break the $SU(N_F)$ chiral symmetry to $SO(N_F)$ via the quark bilinear. Our results are obtained by perturbing the $\mathcal{N}=1$ supersymmetric theory with anomaly-mediated supersymmetry breaking.

    ↳ hep-thhep-phPRL(2021)·24 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.