Wed·Nov 11, 2020Wednesday·November 11, 2020

1. 01*

   Problems of the correspondence principle for the recombination cross section in dark plasma

   Konstantin Belotsky🇷🇺 · Ekaterina Esipova🇷🇺 · Dmitriy Kalashnikov🇷🇺 · Andrei Letunov🇷🇺

   We raise the issues concerning correspondence principle in description of a recombination of oppositely charged particles. These issues have come from cosmological dark matter (DM) problem investigations. Particles possessing Coulomb-like interaction are considered. Such Coulomb-like interaction between DM particles is assumed though the problem seems to be more general. Analysis showed that usage of different semiclassical approaches leads to the apparent discrepancy between numbers of recombination acts. We attempted to find some conditions under which classical cross-section (which relates to multiple soft photon process) reduces to quantum one, which is obtained in semi-classical approximation (Kramers' formula). We just draw attention to this and provide some (not decisive) arguments.

   hep-phhep-thProceedings to the 23rd Workshop What Com…·2 citations
2. 02*

   H1jet, a fast program to compute transverse momentum distributions

   Alexander Lind🇬🇧 · Andrea Banfi🇬🇧

   We present H1jet, a fast code that computes the total cross section and differential distribution in the transverse momentum of a colour singlet. In its current version, the program implements only leading-order $2\to 1$ and $2\to 2$ processes, but could be extended to higher orders. We discuss the processes implemented in H1jet, give detailed instructions on how to implement new processes, and perform comparisons to existing codes. This tool, mainly designed for theorists, can be fruitfully used to assess deviations of selected new physics models from the Standard Model behaviour, as well as to quickly obtain distributions of relevance for Standard Model phenomenology.

   hep-phEPJC(2021)·4 citations
3. 03*

   On the non-cancellation of infrared singularities in collisions of massive quarks

   Fabrizio Caola🇬🇧 · Kirill Melnikov🇩🇪 · Davide Napoletano🇮🇹 · Lorenzo Tancredi🇬🇧

   We discuss the infrared structure of processes with massive quarks in the initial state. It is well known that, starting from next-to-next-to-leading order in perturbative QCD, such processes exhibit a violation of the Bloch-Nordsieck theorem, in that the sum of real and virtual contributions to partonic cross sections contains uncanceled infrared singularities. The main purpose of this paper is to present a simple physical argument that elucidates the origin of these singularities and simplifies the derivation of infrared-singular contributions to heavy-quark initiated cross sections.

   hep-phhep-thPRD(2021)·23 citations
4. 04*

   High $|t|$ diffractive vector meson production at the EIC

   Michal Deak🇺🇸 · Anna M. Stasto🇺🇸 · Mark Strikman🇺🇸

   We investigate the prospects of the diffractive production of $J/\psi$ mesons at large momentum transfer $|t|$ at the future Electron Ion Collider in electron-proton collisions. In particular, we focus on the measurements of the rapidity gap size. The model used for the calculations is based on the diffractive exchange of the Balitsky-Fadin-Kuraev-Lipatov perturbative Pomeron. Calculations for the cross section and the estimates for the rates assuming integrated luminosity of $10\mathrm{f}{\mathrm{b}}^{-1}$ are provided. Two experimental strategies were considered. First, measuring the rapidity gap size directly, by observing the activity in the forward part of the central detector, and second by putting a lower limit on the rapidity gap size in the case when the detector cannot measure forward activity. We find that, it is possible to measure at the EIC the dependence of the cross section on rapidity gap interval up to four units in rapidity. This should allow to measure the change of the cross section by a factor 1.6 expected due to the BFKL exchange. This is possible with the present setup of the detector which projects the coverage up to 3.5 units of rapidity. We conclude however, that the extension of the detector up to higher rapidity, for example to 4.5 would be desirable and provide even better lever arm for testing rapidity gap physics at the EIC.

   hep-phPRD(2021)·6 citations
5. 05*

   The see-saw portal at future Higgs Factories

   Daniele Barducci🇮🇹 · Enrico Bertuzzo🇧🇷 · Andrea Caputo🇮🇱 · Pilar Hernandez🇪🇸 · Barbara Mele🇮🇹

   We consider an extension of the Standard Model with two right-handed singlet fermions with mass at the electroweak scale that induce neutrino masses, plus a generic new physics sector at a higher scale $\Lambda$. We focus on the effective operators of lowest dimension $d=5$, which induce new production and decay modes for the singlet fermions. We assess the sensitivity of future Higgs Factories, such as FCC-ee, CLIC-380, ILC and CEPC, to the coefficients of these operators for various center of mass energies. We show that future lepton colliders can test the cut-off of the theory up to $\Lambda \simeq 500-1000$TeV, surpassing the reach of future indirect measurements of the Higgs and $Z$ boson widths. We also comment on the possibility of determining the underlying model flavor structure should a New Physics signal be observed, and on the impact of higher dimensional $d=6$ operators on the experimental signatures.

   hep-phhep-exhep-thJHEP(2021)·45 citations
6. 06*

   Gravitational Waves as a Big Bang Thermometer

   Andreas Ringwald🇩🇪 · Jan Schütte-Engel🇺🇸 · Carlos Tamarit🇩🇪

   There is a guaranteed background of stochastic gravitational waves produced in the thermal plasma in the early universe. Its energy density per logarithmic frequency interval scales with the maximum temperature $T_{\max }$ which the primordial plasma attained at the beginning of the standard hot big bang era. It peaks in the microwave range, at around $80\mathrm{GHz}[106.75/g_{\ast s}(T_{\max }){]}^{1/3}$, where $g_{\ast s}(T_{\max })$ is the effective number of entropy degrees of freedom in the primordial plasma at $T_{\max }$. We present a state-of-the-art prediction of this Cosmic Gravitational Microwave Background (CGMB) for general models, and carry out calculations for the case of the Standard Model (SM) as well as for several of its extensions. On the side of minimal extensions we consider the Neutrino Minimal SM ($\nu$MSM) and the SM - Axion - Seesaw - Higgs portal inflation model (SMASH), which provide a complete and consistent cosmological history including inflation. As an example of a non-minimal extension of the SM we consider the Minimal Supersymmetric Standard Model (MSSM). Furthermore, we discuss the current upper limits and the prospects to detect the CGMB in laboratory experiments and thus measure the maximum temperature and the effective number of degrees of freedom at the beginning of the hot big bang.

   hep-phastro-ph.COastro-ph.IMhep-exJCAP(2021)·162 citations
7. 07*

   Probing light dark scalars with future experiments

   Enrico Bertuzzo🇧🇷 · Marco Taoso🇮🇹

   We investigate a dark sector containing a pair of light non-degenerate scalar particles, with masses in the MeV-GeV range, coupled to the visible sector through heavier mediators. The heaviest dark state is long-lived, and its decays offer new testable signals. We analyze the prospects for detection with the proposed beam-dump facility SHiP, and the proposed LHC experiments FASER and MATHUSLA. Moreover, we consider bounds from the beam-dump experiment CHARM and from colliders (LEP, LHC and BaBar). We present our results both in terms of an effective field theory, where the heavy mediators have been integrated out, and of a simplified model containing a vector boson mediator, which can be heavy $\gtrsim \mathcal{O}(1)$ TeV, or light $\mathcal{O}(10)$ GeV. We show that future experiments can test large portions of the parameter space currently unexplored, and that they are complementary to future High-Luminosity LHC searches.

   hep-phJHEP(2021)·23 citations
8. 08*

   Neutrino beam-dump experiment with FASER at the LHC

   Krzysztof Jodłowski🇵🇱 · Sebastian Trojanowski🇵🇱

   The neutrino physics program at the LHC, which will soon be initiated by the FASER experiment, will provide unique opportunities for precision studies of neutrino interaction vertices at high energies. This will also open up the possibility to search for beyond the standard model (BSM) particles produced in such interactions in the specific high-energy neutrino beam-dump experiment. In this study, we illustrate the prospects for such searches in models with the dipole or $Z^{\prime }$ portal to GeV-scale heavy neutral leptons. To this end, we employ both the standard signature of new physics that consists of a pair of oppositely-charged tracks appearing in the decay vessel, and the additional types of searches. These include high-energy photons and single scattered electrons. We show that such a variety of experimental signatures could significantly extend the sensitivity reach of the future multi-purpose FASER 2 detector during the High-Luminosity phase of the LHC.

   hep-phJHEP(2021)·67 citations
9. 09*

   Summations of large logarithms by parton showers

   Zoltan Nagy🇩🇪 · Davison E. Soper🇺🇸

   We propose a method to examine how a parton shower sums large logarithms. In this method, one works with an appropriate integral transform of the distribution for the observable of interest. Then, one reformulates the parton shower so as to obtain the transformed distribution as an exponential for which one can compute the terms in the perturbative expansion of the exponent. We apply this general program to the thrust distribution in electron-positron annihilation, using several shower algorithms. Of the approaches that we use, the most generally applicable is to compute some of the perturbative coefficients in the exponent by numerical integration and to test whether they are consistent with next-to-leading-log summation of the thrust logarithms.

   hep-phPRD(2021)·82 citations
10. 10*

    Summations by parton showers of large logarithms in electron-positron annihilation

    Zoltan Nagy🇩🇪 · Davison E. Soper🇺🇸

    In a companion publication, we have explored how to examine the summation of large logarithms in a parton shower. Here, we apply this general program to the thrust distribution in electron-positron annihilation, using several shower algorithms. The method is to work with an appropriate integral transform of the distribution for the observable of interest. Then, we reformulate the parton shower calculation so as to obtain the transformed distribution as an exponential for which we can compute the terms in the perturbative expansion of the exponent.

    hep-ph54 citations
11. 11*

    Light mass window of lepton portal dark matter

    Shohei Okawa🇨🇦 · Yuji Omura🇯🇵

    We explore a novel possibility that dark matter has a light mass below 1GeV in a lepton portal dark matter model. There are Yukawa couplings involving dark matter, left-handed leptons and an extra scalar doublet in the model. In the light mass region, dark matter is thermally produced via its annihilation into neutrinos. In order to obtain the correct relic abundance and avoid collider bounds, a neutral scalar is required to be light while charged scalars need to be heavier than the electroweak scale. Such a mass spectrum is realized by adjusting quartic couplings in the scalar potential or introducing an extra singlet scalar. It turns out that the mass region of 10MeV-10GeV is almost free from experimental and observational constraints. We also point out that searches for extra neutrino flux from galactic dark matter annihilations with neutrino telescopes are the best way to test our model.

    hep-phastro-ph.HEhep-exJHEP(2021)·31 citations
12. 12*

    On $\xi$-process for DVCS-amplitude

    I.V. Anikin🇷🇺

    In this note, we demonstrate in detail the $\xi$-process implementation applied to the deeply virtual Compton scattering amplitude to ensure both the QCD and QED gauge invariance. The presented details are also important for understanding of the contour gauge used in different processes.

    hep-phSymmetry(2020)·4 citations
13. 13*

    Lepton-mediated electroweak baryogenesis, gravitational waves and the $4\tau$ final state at the collider

    Ke-Pan Xie🇰🇷

    An electroweak baryogenesis (EWBG) mechanism mediated by $\tau$ lepton transport is proposed. We extend the Standard Model with a real singlet scalar $S$ to trigger the strong first-order electroweak phase transition (SFOEWPT), and with a set of leptophilic dimension-5 operators to provide sufficient CP violating source. We demonstrate this model is able to generate the observed baryon asymmetry of the universe. This scenario is experimentally testable via either the SFOEWPT gravitational wave signals at the next-generation space-based detectors, or the $pp\to h^{\ast }\to SS\to 4\tau$ process (where $h^{\ast }$ is an off-shell Higgs) at the hadron colliders. A detailed collider simulation shows that a considerable fraction of parameter space can be probed at the HL-LHC, while almost the whole parameter space allowed by EWBG can be reached by the 27 TeV HE-LHC.

    hep-phastro-ph.COJHEP(2021)·33 citations
14. 14*

    An approach of statistical corrections to interactions in hadron resonance gas

    Mahmoud Hanafy (Physics Department, Benha University, Benha, Egypt)🇪🇬 · Muhammad Maher (Helwan University, Physics Department, Ain Helwan, Egypt)🇪🇬

    We propose a new model for hadrons with quantum mechanical attractive and repulsive interactions sensitive to some spatial correlation length parameter inspired by Beth-Uhlenbeck quantum mechanical non-ideal gas model \cite{uhlenbeck1937quantum}. We confront the thermodynamics calculated using our model with a corresponding recent lattice data at four different values of the baryon chemical potential, ${\mu }_{\mathtt{b}}=0,170,340,425$MeV over temperatures ranging from $130$ MeV to $200$MeV and for five values for the correlation length ranging from $0$ to $0.2$fm. For equilibrium temperatures up to the vicinity of the chiral phase transition temperature $\simeq 160$MeV, a decent fitting between the model and the lattice data is observed for different values of $r$, especially at $({\mu }_{\mathtt{b}},r)=(170,0.05),(340,0.1)$, and $(340,0.15)$, where ${\mu }_{\mathtt{b}}$ is in MeV and $r$ is in fm. For vanishing chemical potential, the uncorrelated model ($r=0$), which corresponds to ideal hadron resonance gas model seems to offer the best fit. The quantum hadron correlations seem to be more probable at non-vanishing chemical potentials, especially within the range ${\mu }_{\mathtt{b}}\in [170,340$MeV$]$.

    hep-phhep-thAdv.High Energy Phys.(2021)·2 citations
15. 15*

    Alignment of Yukawa couplings in two Higgs doublet models

    Seong Youl Choi🇰🇷 · Jae Sik Lee🇰🇷 · Jubin Park🇰🇷

    We study the alignment of Yukawa couplings in the framework of general two Higgs doublet models (2HDMs) considering a scenario in which the lightest neutral Higgs boson is purely CP even while the two heavier neutral Higgs bosons are allowed to mix in the presence of nontrivial CP-violating phases in the Higgs potential. Identifying the lightest neutral Higgs boson as the 125 GeV one discovered at the LHC, we find that the alignment of Yukawa couplings without decoupling could be easily achieved in the type-I 2HDM with no much conflict with the current LHC Higgs precision data. Otherwise, we observe that the Yukawa couplings of the lightest Higgs boson could decouple much slowly compared to the Higgs coupling to a pair of massive vector bosons and they significantly deviate from the corresponding SM values even when the deviation of the Higgs to vector boson coupling is below the percent level. On the other hand, independently of 2HDM type and regardless of decoupling, we find a wrong-sign alignment limit of the Yukawa couplings in which the Yukawa couplings to the down-type quarks and/or those to the charged leptons are equal in strength but opposite in sign to the corresponding SM ones. The magnitude and sign of the up-type quark Yukawa couplings remain the same as in the SM. Accordingly, in this limit, all four types of 2HDMs are viable against the LHC Higgs precision data.

    hep-ph5 citations
16. 16*

    Molecular states from $D^{(\ast )}{\bar{D}}^{(\ast )}/B^{(\ast )}{\bar{B}}^{(\ast )}$ and $D^{(\ast )}{D}^{(\ast )}/{\bar{B}}^{(\ast )}{\bar{B}}^{(\ast )}$ interactions

    Zuo-Ming Ding🇨🇳 · Han-Yu Jiang🇨🇳 · Jun He🇨🇳

    In this work, we preform a systematic investigation about hidden heavy and doubly heavy molecular states from the $D^{(\ast )}{\bar{D}}^{(\ast )}/B^{(\ast )}{\bar{B}}^{(\ast )}$ and $D^{(\ast )}{D}^{(\ast )}/{\bar{B}}^{(\ast )}{\bar{B}}^{(\ast )}$ interactions in the quasipotential Bethe-Salpeter equation (qBSE) approach. With the help of Lagrangians with heavy quark and chiral symmetries, interaction potentials are constructed within the one-boson-exchange model in which we include the $\pi$, $\eta$, $\rho$, $\omega$ and $\sigma$ exchanges, as well as $J/\psi$ or ${\rm Y}$ exchange. Possible bound states from the interactions considered are searched for as the pole of scattering amplitude. The results suggest that experimentally observed states, $Z_c(3900)$, $Z_c(4020)$, $Z_b(10610)$, and $Z_b(10650)$, can be related to the $D{\bar{D}}^{\ast }$, $D^{\ast }{\bar{D}}^{\ast }$, $B{\bar{B}}^{\ast }$, and $B^{\ast }{\bar{B}}^{\ast }$ interactions with quantum numbers $I^G(J^P)=1^{+}(1^{+})$, respectively. The $D{\bar{D}}^{\ast }$ interaction is also attractive enough to produce a pole with $0^{+}(0^{+})$ which is related to the $X(3872)$. Within the same theoretical frame, the existence of $D\bar{D}$ and $B\bar{B}$ molecular states with $0(0^{+})$ are predicted. The possible $D^{\ast }{\bar{D}}^{\ast }$ molecular states with $0(0^{+},1^{+},2^{+})$ and $1(0^{+})$ and their bottom partners are also suggested by the calculation. In the doubly heavy sector, no bound state is produced from the $DD/\bar{B}\bar{B}$ interaction while a bound state is found with $0(1^{+})$ from $D{D}^{\ast }/\bar{B}{\bar{B}}^{\ast }$ interaction. The $D^{\ast }{D}^{\ast }/{\bar{B}}^{\ast }{\bar{B}}^{\ast }$ interaction produces three molecular states with $0(1^{+})$, $0(2^{+})$ and $1(2^{+})$.

    hep-phEPJC(2020)·65 citations
17. 17*

    Supersymmetric gauged U(1)${}_{L_{\mu }-L_{\tau }}$ model for electron and muon $(g-2)$ anomaly

    Heerak Banerjee🇮🇳 · Bhaskar Dutta🇺🇸 · Sourov Roy🇮🇳

    Minimal gauged U(1)${}_{L_{\mu }-L_{\tau }}$ models can provide for an additional source for the muon anomalous magnetic moment however it is difficult to accommodate the discrepancy in the electron magnetic moment in tandem. Owing to the relative sign between the discrepancies in these quantities, it seems unlikely that they arise from the same source. We show that a supersymmetric (SUSY) gauged U(1)${}_{L_{\mu }-L_{\tau }}$ model can accommodate both the muon and electron anomalous magnetic moments in a very simple and intuitive scenario, without utilizing lepton flavor violation. The currently allowed parameter space in this kind of a scenario is constrained from the latest LHC and various low energy experimental data,e.g., recent COHERENT data, CCFR, Borexino, BaBaR, supernova etc. These constraints, in conjunction with the requirement to explain both lepton magnetic moments, lead to an upper bound on the first generation slepton mass, a lower bound on the second generation slepton mass and constricts the allowed range for the new gauge boson mass and coupling. The scheme can be probed at the ongoing COHERENT and Coherent CAPTAIN-Mills experiments and at future experiments, e.g., DUNE, BELLE-II etc.

    hep-phhep-exJHEP(2021)·25 citations
18. 18*

    Analysis of the $P_{cs}(4459)$ as the hidden-charm pentaquark state with QCD sum rules

    Zhi-Gang Wang🇨🇳

    In this article, we study the scalar-diquark-scalar-diquark-antiquark type $udsc\bar{c}$ pentaquark state with the QCD sum rules, the predicted mass $M_P=4.47\pm 0.11\mathrm{GeV}$ is in excellent agreement with the experimental data $4458.8\pm 2.9{}_{-1.1}^{+4.7}\text{mbox}MeV$ from the LHCb collaboration, and supports assigning the $P_{cs}(4459)$ to be the hidden-charm pentaquark state with the spin-parity $J^P={\frac{1}{2}}^{-}$. We take into account the flavor $SU(3)$ mass-breaking effect, and estimate the mass spectrum of the diquark-diquark-antiquark type $udsc\bar{c}$ pentaquark states with the strangeness $S=-1$.

    hep-phInt.J.Mod.Phys.A(2021)·86 citations
19. 19*

    Composite Higgs scenario in mass-split models

    Oliver Witzel🇺🇸 · Anna Hasenfratz🇺🇸 · Curtis T. Peterson🇺🇸

    Mass-split composite Higgs models naturally accommodate the experimental observation of a light 125 GeV Higgs boson and predict a large scale separation to other heavier resonances. We explore the SU(3) gauge system with four light (massless) and six heavy (massive) flavors by performing numerical simulations. Since the underlying system with degenerate and massless ten flavors appears to be infrared conformal, this system inherits conformal hyperscaling and allows to study near-conformal dynamics. Carrying out nonperturbative lattice field theory simulations, we present the low-lying particle spectrum. We demonstrate hyperscaling, predict the anomalous mass dimension of the corresponding conformal fixed point, and show that in the investigated mass regime the data are described by dilaton chiral perturbation theory. The proximity of a conformal infrared fixed point leads to a highly predictive particle spectrum which is quite distinct from QCD. Further we present initial results of our finite temperature investigations.

    hep-phhep-latPoS(2021)·6 citations
20. 20*

    Scalar resonances in the $D^{+}\to K^{-}{K}^{+}{K}^{+}$ decay

    L. Roca🇪🇸 · E. Oset🇪🇸

    We study theoretically the resonant structure of the double Cabibbo suppressed $D^{+}\to K^{-}{K}^{+}{K}^{+}$ decay. We start from an elementary production diagram, considered subleading in previous approaches, which cannot produce a final $K^{-}{K}^{+}$ pair at the tree level but which we show to be able to provide the strength of the decay through final meson-meson state interaction. The different meson-meson elementary productions are related through SU(3) and the final rescattering is implemented from a suitable implementation of unitary extensions of ChPT which generate dynamically the scalar resonances $f_0(980)$ and $a_0(980)$. We obtain a good agreement with recent experimental data from the LHCb collaboration with a minimal freedom in the fit and show the dominance of the $a_0(980)$ contribution close to the threshold of the $K^{-}{K}^{+}$ spectrum.

    hep-phPRD(2021)·23 citations
21. 21*

    Angular distributions in Monte Carlo event generation of weak single-pion production

    K. Niewczas🇧🇪 · A. Nikolakopoulos🇧🇪 · J. T. Sobczyk🇵🇱 · N. Jachowicz🇧🇪 · R. González-Jiménez🇪🇸

    One of the substantial sources of systematic errors in neutrino oscillation experiments that utilize neutrinos from accelerator sources stems from a lack of precision in modeling single-pion production (SPP). Oscillation analyses rely on Monte Carlo event generators (MC), providing theoretical predictions of neutrino interactions on nuclear targets. Pions produced in these processes provide a significant fraction of oscillation signal and background on both elementary scattering and detector simulation levels. Thus, it is of critical importance to develop techniques that will allow us to accommodate state-of-the-art theoretical models describing SPP into MCs. In this work, we investigate various algorithms to implement single-pion production models in Monte Carlo event generators. Based on comparison studies, we propose a novel implementation strategy that combines satisfactory efficiency with high precision in reproducing details of theoretical models predictions, including pion angular distributions. The proposed implementation is model-independent, thereby providing a framework that can include any model for SPP. We have tested the new algorithm with the Ghent Low Energy Model for single-pion production implemented in the NuWro Monte Carlo event generator.

    hep-phPRD(2021)·11 citations
22. 22*

    Yang-Mills Gauss law and the heavy quark binding energy in the presence of a dimension-2 gluon condensate

    Jordan Wilson-Gerow🇨🇦

    We study the binding energy of a heavy quark-antiquark ($q\bar{q}$) pair using the first-order path integral formalism. This makes the Yang-Mills constraint equation explicit, and highlights that it is valid without relying on a semiclassical approximation. A generalized gauge-covariant Coulomb gauge is chosen to allow for a decomposition of the chromoelectric field into a gauge-covariant generalization of transverse and longitudinal parts. This decomposition makes it clear that the $q\bar{q}$ binding energy is determined solely by the solution to the constraint equation. Assuming that the low-energy physics is dominated by the existence of a dimension-2 gluon condensate, we develop an asymptotic series solution to the constraint equation and thus to the $q\bar{q}$ binding energy. We predict a QCD string tension in terms of the condensate strength and quadratic Casimir eigenvalues, and relate our result to results coming from OPE analyses.

    hep-phhep-th1 citation
23. 23*

    Flavor mixing and renormalization in a perturbation theory

    Chang-Hun Lee🇹🇼

    The renormalization of theories with flavor mixing is discussed, and it is shown that the physical unstable particles should be interpreted as quasiparticles which cannot be regarded as external states. Several popular beliefs on renormalization are disproved accordingly, and the limitations of physical renormalization schemes are discussed. In addition, the properties of unstable particles with flavor mixing such as decay widths are studied from scattering mediated by them.

    hep-ph3 citations
24. 24*

    On-shell effective theory for higher-spin dark matter

    Adam Falkowski🇫🇷 · Giulia Isabella🇫🇷 · Camila S. Machado🇩🇪

    We apply the on-shell amplitude techniques in the domain of dark matter. Without evoking fields and Lagrangians, an effective theory for a massive spin-$S$ particle is defined in terms of on-shell amplitudes, which are written down using the massive spinor formalism. This procedure greatly simplifies the study of theories with a higher-spin dark matter particle. In particular, it provides an efficient way to calculate the rates of processes controlling dark matter production, and offers better physical insight into how different processes depend on the relevant scales in the theory. We demonstrate the applicability of these methods by exploring two scenarios where higher-spin DM is produced via the freeze-in mechanism. One scenario is minimal, involving only universal gravitational interactions, and is compatible with dark matter masses in a very broad range from sub-TeV to the GUT scale. The other scenario involves direct coupling of higher-spin DM to the Standard Model via the Higgs intermediary, and leads to a rich phenomenology, including dark matter decay signatures.

    hep-phhep-thSciPost Phys.(2021)·35 citations
25. 25*

    Exploring Early Dark Energy solution to the Hubble tension with Planck and SPTPol data

    Anton Chudaykin🇷🇺 · Dmitry Gorbunov🇷🇺 · Nikita Nedelko🇷🇺

    A promising idea to resolve the long standing Hubble tension is to postulate a new subdominant dark-energy-like component in the pre-recombination Universe which is traditionally termed as the Early Dark Energy (EDE). However, as shown in Refs. \cite{Hill:2020osr,Ivanov:2020ril} the cosmic microwave background (CMB) and large-scale structure (LSS) data impose tight constraints on this proposal. Here, we revisit these strong bounds considering the Planck CMB temperature anisotropy data at large angular scales and the SPTPol polarization and lensing measurements. As advocated in Ref. \cite{Chudaykin:2020acu}, this combined data approach predicts the CMB lensing effect consistent with the $\Lambda$CDM expectation and allows one to efficiently probe both large and small angular scales. Combining Planck and SPTPol CMB data with the full-shape BOSS likelihood and information from photometric LSS surveys in the EDE analysis we found for the Hubble constant $H_0=69.79\pm 0.99\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ and for the EDE fraction $f_{\mathrm{EDE}}<0.094(2\sigma )$. These bounds obtained without including a local distance ladder measurement of $H_0$ (SH0ES) alleviate the Hubble tension to a $2.5\sigma$ level. Including further the SH0ES data we obtain $H_0=71.81\pm 1.19\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ and $f_{\mathrm{EDE}}=0.088\pm 0.034$ in full accordance with SH0ES. We also found that a higher value of $H_0$ does not significantly deteriorate the fit to the LSS data. Overall, the EDE scenario is (though weakly) favoured over $\Lambda$CDM even after accounting for unconstrained directions in the cosmological parameter space. We conclude that the large-scale Planck temperature and SPTPol polarization measurements along with LSS data do not rule out the EDE model as a resolution of the Hubble tension. This paper underlines the importance of the CMB lensing effect for robust constraints on the EDE scenario.

    ↳ astro-ph.COhep-phPRD(2021)·55 citations
26. 26*

    QCD phase structure in strong magnetic fields

    H.-T. Ding🇨🇳 · S.-T. Li🇨🇳 · Q. Shi🇨🇳 · A. Tomiya🇺🇸 · X.-D. Wang🇨🇳 · Y. Zhang🇨🇳

    In this proceedings we discuss the natural connection between the reduction of neutral pion mass in the vacuum, and the magnetic catalysis as well as the reduction of transition temperature in the external magnetic field. We also present the first results on fluctuations of and correlations among conserved charges in strong magnetic fields from lattice QCD computations.

    ↳ hep-lathep-phhep-thnucl-ex+1Acta Phys.Polon.Supp.(2021)·14 citations
27. 27*

    Constraint on hybrid stars with gravitational wave events

    Kilar Zhang🇹🇼 · Feng-Li Lin🇹🇼

    Motivated by the recent discoveries of compact objects from LIGO/Virgo observations, we study the possibility of identifying some of these objects as compact stars made of dark matter called dark stars, or the mix of dark and nuclear matters called hybrid stars. In particular, in GW190814, a new compact object with 2.6 $M_{\odot }$ is reported. This could be the lightest black hole, the heaviest neutron star, and a dark or hybrid star. In this work, we extend the discussion on the interpretations of the recent LIGO/Virgo events as hybrid stars made of various self-interacting dark matter (SIDM) in the isotropic limit. We pay particular attention to the saddle instability of the hybrid stars which will constrain the possible SIDM models.

    ↳ astro-ph.HEgr-qchep-phhep-thUniverse(2020)·17 citations
28. 28*

    Generalized elastic positivity bounds on interacting massive spin-2 theories

    Zi-Yue Wang🇨🇳 · Cen Zhang🇨🇳 · Shuang-Yong Zhou🇨🇳

    We use generalized elastic positivity bounds to constrain the parameter space of multi-field spin-2 effective field theories. These generalized bounds involve inelastic scattering amplitudes between particles with different masses, which contain kinematic singularities even in the $t=0$ limit. We apply these bounds to the pseudo-linear spin-2 theory, the cycle spin-2 theory and the line spin-2 theory respectively. For the pseudo-linear theory, we exclude the remaining operators that are unconstrained by the usual elastic positivity bounds, thus excluding all the leading (or highest cutoff) interacting operators in the theory. For the cycle and line theory, our approach also provides new bounds on the Wilson coefficients previously unconstrained, bounding the parameter space in both theories to be a finite region ({\it i.e.}, every Wilson coefficient being constrained from both sides). To help visualize these finite regions, we sample various cross sections of them and estimate the total volumes.

    ↳ hep-thgr-qchep-phJHEP(2021)·35 citations
29. 29*

    Jas4pp -- a Data-Analysis Framework for Physics and Detector Studies

    S. V. Chekanov🇺🇸 · G. Gavalian🇺🇸 · N. A. Graf🇺🇸

    This paper describes the Jas4pp framework for exploring physics cases and for detector-performance studies of future particle collision experiments. Jas4pp is a multi-platform Java program for numeric calculations, scientific visualization in 2D and 3D, storing data in various file formats and displaying collision events and detector geometries. It also includes complex data-analysis algorithms for function minimisation, regression analysis, event reconstruction (such as jet reconstruction), limit settings and other libraries widely used in particle physics. The framework can be used with several scripting languages, such as Python/Jython, Groovy and JShell. Several benchmark tests discussed in the paper illustrate significant improvements in the performance of the Groovy and JShell scripting languages compared to the standard Python implementation in C. The improvements for numeric computations in Java are attributed to recent enhancements in the Java Virtual Machine.

    ↳ physics.comp-phhep-phnucl-exComput.Phys.Commun.(2021)·3 citations
30. 30*

    ETHOS -- An Effective Theory of Structure Formation: Impact of Dark Acoustic Oscillations on Cosmic Dawn

    Julian B. Muñoz🇺🇸 · Sebastian Bohr🇮🇸 · Francis-Yan Cyr-Racine🇺🇸 · Jesús Zavala🇮🇸 · Mark Vogelsberger🇺🇸

    Upcoming data of the 21-cm hydrogen line during cosmic dawn ($z\sim 10-30$) will revolutionize our understanding of the astrophysics of the first galaxies. Here we present a case study on how to exploit those same measurements to learn about the nature of dark matter (DM) at small scales. Focusing on the Effective Theory of Structure Formation (ETHOS) paradigm, we run a suite of simulations covering a broad range of DM microphysics, connecting the output of $N$-body simulations to dedicated 21-cm simulations to predict the evolution of the 21-cm signal across the entire cosmic dawn. We find that observatories targeting both the global signal and the 21-cm power spectrum are sensitive to all ETHOS models we study, and can distinguish them from CDM if the suppression wavenumber is smaller than $k\approx 300h/$Mpc, even when accounting for feedback with a phenomenological model. This is an order of magnitude smaller comoving scales than currently constrained by other data sets, including the Lyman-$\alpha$ forest. Moreover, if a prospective 21-cm detection confirmed a deficiency of power at small scales, we show that ETHOS models with strong dark acoustic oscillations can be discriminated from the pure suppression of warm dark matter, showing the power of 21-cm data to understand the behavior of DM at the smallest physical scales.

    ↳ astro-ph.COastro-ph.GAhep-phPRD(2021)·37 citations
31. 31*

    A New Spin on the Weak Gravity Conjecture

    Lars Aalsma🇺🇸 · Alex Cole🇳🇱 · Gregory J. Loges🇺🇸 · Gary Shiu🇺🇸

    The mild form of the Weak Gravity Conjecture states that quantum or higher-derivative corrections should decrease the mass of large extremal charged black holes at fixed charge. This allows extremal black holes to decay, unless protected by a symmetry (such as supersymmetry). We reformulate this conjecture as an integrated condition on the effective stress tensor capturing the effect of quantum or higher-derivative corrections. In addition to charged black holes, we also consider rotating BTZ black holes and show that this condition is satisfied as a consequence of the $c$-theorem, proving a spinning version of the Weak Gravity Conjecture. We also apply our results to a five-dimensional boosted black string with higher-derivative corrections. The boosted black string has a $\text{BTZ}\times S^2$ near-horizon geometry and, after Kaluza-Klein reduction, describes a four-dimensional charged black hole. Combining the spinning and charged Weak Gravity Conjecture we obtain positivity bounds on the five-dimensional Wilson coefficients that are stronger than those obtained from charged black holes alone.

    ↳ hep-thhep-phJHEP(2021)·31 citations
32. 32*

    Many Phases of Generalized 3D Instanton Crystals

    Matti Jarvinen🇰🇷 · Vadim Kaplunovsky🇺🇸 · Jacob Sonnenschein🇮🇱

    Nuclear matter at large number of colors is necessarily in a solid phase. In particular holographic nuclear matter takes the form of a crystal of instantons of the flavor group. In this article we initiate the analysis of the three-dimensional crystal structures and the orientation patterns for the two-body potential that follows from holographic duality. The outcome of the analysis includes several unexpected results. We perform simulations of ensembles of O(10000) instantons whereby we identify the lattice structure and orientations for the different values of the weight factors of the non-Abelian orientation terms in the two-body potential. The resulting phase diagram is surprisingly complex, including a variety of ferromagnetic and antiferromagnetic crystals with various global orientation patterns, and various "non-Abelian" crystals where orientations have no preferred direction. The latter include variants of face-centered-cubic, hexagonal, and simple cubic crystals which may have remarkably large or small aspect ratios. The simulation results are augmented by analytic analysis of the long-distance divergences, and numerical computation of the (divergence free) energy differences between the non-Abelian crystals, which allows us to precisely determine the structure of the phase diagram.

    ↳ hep-thhep-phnucl-thSciPost Phys.(2021)·11 citations
33. 33*

    Gravitational tests of electroweak relaxation

    Daniele Barducci🇮🇹 · Enrico Bertuzzo🇧🇷 · Martín Arteaga Tupia🇧🇷

    We consider a scenario in which the electroweak scale is stabilized via the relaxion mechanism during inflation, focussing on the case in which the back-reaction potential is generated by the confinement of new strongly interacting vector-like fermions. If the reheating temperature is sufficiently high to cause the deconfinement of the new strong interactions, the back-reaction barrier then disappears and the Universe undergoes a second relaxation phase. This phase stops when the temperature drops sufficiently for the back-reaction to form again. We identify the regions of parameter space in which the second relaxation phase does not spoil the successful stabilization of the electroweak scale. In addition, the generation of the back-reaction potential that ends the second relaxation phase can be associated to a strong first order phase transition. We then study when such transition can generate a gravitational wave signal in the range of detectability of future interferometer experiments.

    ↳ astro-ph.COgr-qchep-lathep-ph+1JHEP(2021)·7 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.