Fri·Aug 28, 2020Friday·August 28, 2020

1. 01*

   Prospects of Indirect Detection for the Heavy S3 Dark Doublet

   C. Espinoza🇲🇽 · M. Mondragón🇲🇽

   We present an analysis of the Dark S3 model in the heavy DM mass region, this model features an S3 symmetric extension of the scalar sector of the SM including a scalar $SU(2)$ doublet dark matter candidate. We use publicly available tools to compute, in addition to conventional physical constraints on the parameter space of the model, the Sommerfeld enhancement factors for the present day annihilation cross section and the likelihood profile for a simulation of an observation run by the Cherenkov Telescope Array of the Coma Berenices dwarf galaxy. Our results disfavour masses above $\sim$5 TeV mainly because of overproduction of dark matter not consistent with the relic abundance observations; we also find a moderately large region with masses in between 1.2 and 4.9 TeV which predict the correct value of the DM relic and in addition have a light scalar with the characteristics of the SM Higgs boson (i.e. within the decoupling limit akin to the THDM). Comparison of our results with model independent exclusion curves from HESS and other CTA simulations show that these limits fall short only an order of magnitude in the value of the annihilation cross section in order to exclude the best fit point of the model.

   hep-ph7 citations
2. 02*

   The Scale of Superpartner Masses and Electroweakino Searches at the High-Luminosity LHC

   Jia Liu🇺🇸 · Navin McGinnis🇺🇸 · Carlos E.M. Wagner🇺🇸 · Xiao-Ping Wang🇺🇸

   Searches for weakly interacting particles is one of the main goals of the high luminosity LHC run. In this work we study the well motivated cases of electroweakinos with mostly Wino and Bino components. We show the relevance of squark induced t-channel production in defining the production cross section and hence the LHC reach. Moreover, a realistic evaluation of the decay branching ratios show a strong dependence on the sign of $\mu$ and, for negative values of $\mu$, on the relative size of the ratio of $\mu$ to the gaugino masses compared with tan$\beta$. Overall, unless it is kinematically suppressed, or specific conditions are fulfilled, the Higgs decay channel is the most significant one, and the trilepton channel becomes subdominant with respect to final states including bottom quarks. Although the properties are different than in the Higgsino-Bino case, also in this case the discovery reach extends to mass values that are significantly larger than the ones probed at current luminosities, leading to a strong motivation for the search for electroweakinos in the high luminosity LHC run.

   hep-phhep-exJHEP(2020)·6 citations
3. 03*

   Constraints on Decaying Sterile Neutrinos from Solar Antineutrinos

   Matheus Hostert🇺🇸 · Maxim Pospelov🇺🇸

   Solar neutrino experiments are highly sensitive to sources of $\nu \to \overline{\nu }$ conversions in the ${}^8$B neutrino flux. In this work we adapt these searches to non-minimal sterile neutrino models recently proposed to explain the LSND, MiniBooNE, and reactor anomalies. The production of such sterile neutrinos in the Sun, followed the decay chain ${\nu }_4\to \nu \varphi \to \nu \nu \overline{\nu }$ with a new scalar $\varphi$ results in upper limits for the neutrino mixing $|U_{e4}{|}^2$ at the per mille level. We conclude that a simultaneous explanations of all anomalies is in tension with KamLAND, Super-Kamiokande, and Borexino constraints on the flux of solar antineutrinos. We then present other minimal models that violate parity or lepton number, and discuss the applicability of our constraints in each case. Future improvements can be expected from existing Borexino data as well as from future searches at Super-Kamiokande with added Gd.

   hep-phhep-exPRD(2021)·27 citations
4. 04*

   Strange quark helicity in the proton from chiral effective theory

   X.G. Wang🇦🇺 · Chueng-Ryong Ji🇺🇸 · W. Melnitchouk🇺🇸 · Y. Salamu🇨🇳 · A.W. Thomas🇦🇺 · P. Wang🇨🇳

   We compute the helicity-dependent strange quark distribution in the proton in the framework of chiral effective theory. Starting from the most general chiral SU(3) Lagrangian that respects Lorentz and gauge invariance, we derive the complete set of hadronic splitting functions at the one meson loop level, including the octet and decuplet rainbow, tadpole, Kroll-Ruderman and octet-decuplet transition configurations. By matching hadronic and quark level operators, we obtain generalized convolution formulas for the quark distributions in the proton in terms of hadronic splitting functions and quark distributions in the hadronic configurations, and from these derive model-independent relations for the leading nonanalytic behavior of their moments. Within the limits of parameters of the Pauli-Villars regulators derived from inclusive hyperon production, we find that the polarized strange quark distribution is rather small and mostly negative.

   hep-phhep-exhep-latnucl-thPRD(2020)·7 citations
5. 05*

   Muon Anomalous Magnetic Moment in Two Higgs Doublet Models with Vector-Like Leptons

   Mariana Frank🇨🇦 · Ipsita Saha🇯🇵

   We show that inclusion of a single generation of vector-like leptons in the Two-Higgs Doublet Models significantly enlarges the allowed parameter space consistent with the muon anomalous magnetic moment, as well as with other theoretical and experimental constraints. While previously $(g-2{)}_{\mu }$ could only be resolved in Type-X scenario by requiring a light pseudoscalar Higgs boson and large $\tan \beta$, contributions of vector-like leptons via two-loop Barr Zee diagrams broaden the allowed parameter space, allowing $\tan \beta$ as low as 10 and pseudoscalar masses as large as $\mathcal{O}$(1 TeV) while fulfilling the stringent constraints from precision and flavor observable. Similar results are obtained for Type-II scenarios, but there the parameter space is more restricted by flavor observables.

   hep-phPRD(2020)·40 citations
6. 06*

   Scrutinizing Vacuum Stability in IDM with Type-III Inverse seesaw

   Priyotosh Bandyopadhyay🇮🇳 · Shilpa Jangid🇮🇳 · Manimala Mitra🇮🇳

   We consider the extension of the Standard Model (SM) with an inert Higgs doublet that also contains two or three sets of $SU(2{)}_L$ triplet fermions with hypercharge zero and analyze the stability of electroweak vacuum for the scenarios. The model represents a Type-III inverse seesaw mechanism for neutrino mass generation with a Dark matter candidate.An effective potential approach calculation with two-loop beta function have been carried out in deciding the fate of the electroweak vacuum. Weak gauge coupling $g_2$ shows a different behaviour as compared to the Standard Model. The modified running of $g_2$, along with the Higgs quartic coupling and Type-III Yukawa couplings become crucial in determining the stability of electroweak vacuum. The interplay between two and three generations of such triplet fermions reveals that extensions with two generations is favoured if we aspire for Planck scale stability. Bounds on the Higgs quartic couplings, Type-III Yukawa and number of triplet fermion generations are drawn for different mass scale of Type-III fermions. The phenomenologies of inert doublet and Type-III fermions at the LHC and other experiments are commented upon.

   hep-phJHEP(2021)·17 citations
7. 07*

   Heating triangle singularities in heavy ion collisions

   Luciano M. Abreu (Univ. Federal Bahia)🇧🇷 · Felipe J. Llanes-Estrada (Univ. Complutense Madrid)🇪🇸

   We predict that triangle singularities of hadron spectroscopy can be strongly affected in heavy ion collisions. To do it we examine various effects on the singularity-inducing triangle loop of finite temperature in the terminal hadron phase. It appears that peaks seen in central heavy ion collisions are more likely to be hadrons than rescattering effects under two conditions. First, the flight-time of the intermediate hadron state must be comparable to the lifetime of the equilibrated fireball (else, the reaction mostly happens in vacuo after freeze out). Second, the medium effect over the triangle-loop particle mass or width must be sizeable. When these (easily checked) conditions are met, the medium quickly reduces the singularity: at T about 150 MeV, even by two orders of magnitude, acting then as a spectroscopic filter.

   hep-phnucl-thEPJC(2021)·15 citations
8. 08*

   CutLang as an Analysis Description Language for Introducing Students to Analyses in Particle Physics

   Aytul Adiguzel (1 and 4)🇹🇷 · Orhan Cakir (2)🇹🇷 · Umit Kaya (3)🇹🇷 · V. Erkcan Ozcan (3 and 4)🇹🇷 · Sertac Ozturk (5)🇹🇷 · Sezen Sekmen (6)🇰🇷 · Ilkay Turk Cakir (7)🇹🇷 · N. Gokhan Unel (8) ((1) Istanbul University, (2) Ankara University, (3) Bogazici University, (4) Feza Gursey Center for Physics and Mathematics, (5) Tokat Gaziosmanpasa University, (6) Kyungpook National University, (7) Giresun University, (8) University of California, Irvine)🇺🇸

   The fifth edition of the "Computing Applications in Particle Physics" school was held on 3-7 February 2020, at Istanbul University, Turkey. This particular edition focused on the processing of simulated data from the Large Hadron Collider collisions using an Analysis Description Language and its runtime interpreter called CutLang. 24 undergraduate and 6 graduate students were initiated to collider data analysis during the school. After 3 days of lectures and exercises, the students were grouped into teams of 3 or 4 and each team was assigned an analysis publication from ATLAS or CMS experiments. After 1.5 days of independent study, each team was able to reproduce the assigned analysis using CutLang.

   hep-phphysics.ed-phEur.J.Phys.(2021)·7 citations
9. 09*

   Revisiting the production of $J/\psi$ pairs at the LHC

   A.A. Prokhorov🇷🇺 · A.V. Lipatov🇷🇺 · M.A. Malyshev🇷🇺 · S.P. Baranov🇷🇺

   We consider the prompt double $J/\psi$ production in $pp$ collisions at the LHC in the framework of $k_T$-factorization QCD approach. Using the fragmentation mechanism, we evaluate the color octet contributions to the production cross sections taking into account the combinatorial effects of multiple gluon radiation in the initial state driven by the Ciafaloni-Catani-Fiorani-Marchesini evolution equation. We demonstrate the importance of these contributions in a certain kinematical region covered by the CMS and ATLAS measurements. On the other hand, the experimental data taken by the LHCb Collaboration at forward rapidities and moderate transverse momenta can be described well by $\mathcal{O}({\alpha }_s^4)$ color singlet terms and contributions from the double parton scattering mechanism. The extracted value of the effective cross section ${\sigma }_{\mathrm{eff}}=17.5\pm 4.1$~mb is compatible with many other estimations based on different final states.

   hep-phEPJC(2020)·14 citations
10. 10*

    The minimal seesaw and leptogenesis models

    Zhi-zhong Xing🇨🇳 · Zhen-hua Zhao🇨🇳

    Given its briefness and predictability, the minimal seesaw -- a simplified version of the canonical seesaw mechanism with only two right-handed neutrino fields -- has been studied in depth and from many perspectives, and now it is being pushed close to a position of directly facing experimental tests. This article is intended to provide an up-to-date review of various phenomenological aspects of the minimal seesaw and its associated leptogenesis mechanism in neutrino physics and cosmology. Our focus is on possible flavor structures of such benchmark seesaw and leptogenesis scenarios and confronting their predictions with current neutrino oscillation data and cosmological observations. In this connection particular attention will be paid to the topics of lepton number violation, lepton flavor violation, discrete flavor symmetries, CP violation and antimatter of the Universe.

    hep-phRept.Prog.Phys.(2021)·83 citations
11. 11*

    A natural interpretation on the data of ${\Lambda }_c\to \Sigma \pi$

    Hong-Wei Ke🇨🇳 · Xue-Qian Li🇨🇳

    Even though the Standard Model (SM) has achieved great success, its application to the field of low energies still lacks solid foundation due to our limited knowledge on non-perturbative QCD. Practically, all theoretical calculations of the hadronic transition matrix elements are based various phenomenological models. There indeed exist some anomalies in the field which are waiting for interpretations. The goal of this work is trying to solve one of the anomalies: the discrepancy between the theoretical prediction on the sign of the up-down asymmetry parameter of ${\Lambda }_c\to \Sigma \pi$ and the experimental measurement. In the literatures several authors calculated the rate and determined the asymmetry parameter within various schemes, but there exist obvious loopholes in those adopted scenarios. To solve the discrepancy between theory and data, we suggest that not only the direct transition process contributes to the observed ${\Lambda }_c\to \Sigma \pi$, but also other portals such as ${\Lambda }_c\to \Lambda \rho$ also play a substantial role via an isospin-conserving re-scattering $\Lambda \rho \to \Sigma \pi$. Taking into account of the effects induced by the final state interaction, we re-evaluate the relevant quantities. Our numerical results indicate that the new theoretical prediction based on this scenario involving an interference between the direct transition of ${\Lambda }_c\to \Sigma \pi$ and the portal ${\Lambda }_c\to \Lambda \rho \to \Sigma \pi$ can make both the decay rate and sign of the asymmetry parameter to be consistent with data.

    hep-phPRD(2020)·6 citations
12. 12*

    Dark Photon Dark Matter in the minimal $B-L$ Model

    Gongjun Choi🇨🇳 · Tsutomu T. Yanagida🇨🇳 · Norimi Yokozaki🇯🇵

    The extension of the Standard model (SM) with three heavy right handed neutrinos, a complex scalar and the gauged $U(1{)}_{\mathrm{B}-\mathrm{L}}$ symmetry (the minimal $B-L$ model) is considered the most compelling minimal one: the presence and the out-of-equilibrium decay of the heavy right handed neutrinos can account for the small masses of the active neutrinos and the baryon asymmetry of the universe. A natural accompanying question concerns whether the minimal $B-L$ model can naturally accommodate an interesting dark matter (DM) candidate. We study the possibility where the current DM population is explained by the gauge boson of $U(1{)}_{\mathrm{B}-\mathrm{L}}$ symmetry. We discuss how the minimal set-up originally aimed at the seesaw mechanism and the leptogenesis is connected to conditions making the gauge boson promoted to a DM candidate.

    hep-phJHEP(2021)·15 citations
13. 13*

    Electroweak Couplings of the Higgs Boson at a Multi-TeV Muon Collider

    Tao Han🇺🇸 · Da Liu🇺🇸 · Ian Low🇺🇸 · Xing Wang🇺🇸

    We estimate the expected precision at a multi-TeV muon collider for measuring the Higgs boson couplings with electroweak gauge bosons, $HVV$ and $HHVV(V=W^{\pm },Z)$, as well as the trilinear Higgs self-coupling $HHH$. At very high energies both single and double Higgs productions rely on the vector-boson fusion (VBF) topology. The outgoing remnant particles have a strong tendency to stay in the very forward region, leading to the configuration of the "inclusive process" and making it difficult to isolate $ZZ$ fusion events from the $WW$ fusion. In the single Higgs channel, we perform a maximum likelihood analysis on $HWW$ and $HZZ$ couplings using two categories: the inclusive Higgs production and the 1-muon exclusive signal. In the double Higgs channel, we consider the inclusive production and study the interplay of the trilinear $HHH$ and the quartic $VVHH$ couplings, by utilizing kinematic information in the invariant mass spectrum. We find that at a centre-of-mass energy of 10 TeV (30 TeV) with an integrated luminosity of 10 ab${}^{-1}$ (90 ab${}^{-1}$), one may reach a 95\% confidence level sensitivity of 0.073\% (0.023\%) for $WWH$ coupling, 0.61\% (0.21\%) for $ZZH$ coupling, 0.62\% (0.20\%) for $WWHH$ coupling, and 5.6\% (2.0\%) for $HHH$ coupling. For dim-6 operators contributing to the processes, these sensitivities could probe the new physics scale $\Lambda$ in the order of $1-10$ ($2-20$) TeV at a 10 TeV (30 TeV) muon collider.

    hep-phhep-exPRD(2021)·141 citations
14. 14*

    Conformal window from conformal expansion

    Jong-Wan Lee🇰🇷

    We study the conformal window of asymptotically free gauge theories containing $N_f$ flavors of fermion matter transforming to the vector and two-index representations of $SO(N),SU(N)$ and $Sp(2N)$ gauge groups. For $SO(N)$ we also consider the spinorial representation. We determine the critical number of flavors $N_f^{\mathrm{cr}}$, corresponding to the lower end of the conformal window, by using the conjectured critical condition on the anomalous dimension of the fermion bilinear at an infrared fixed point, ${\gamma }_{\bar{\psi }\psi }=1$ or equivalently ${\gamma }_{\bar{\psi }\psi }(2-{\gamma }_{\bar{\psi }\psi })=1$. To compute the anomalous dimension we employ the Banks-Zaks conformal expansion up to the $4$th order in ${\Delta }_{N_f}=N_f^{\mathrm{AF}}-N_f$ with $N_f^{\mathrm{AF}}$ denoting the onset of the loss of asymptotic freedom, where we show that the latter critical condition provides a better performance along with this conformal expansion. To quantify the uncertainties in our analysis, which potentially originate from nonperturbative effects, we propose two distinct approaches by assuming the large order behavior of the conformal expansion separately, either convergent or divergent asymptotic. In the former case, we take the difference in the Padé approximants to the two definitions of the critical condition, whereas in the latter case the truncation error associated with the singularity in the Borel plane is taken into account. Our results are further compared to other analytical methods as well as lattice results available in the literature. In particular, we find that $SU(2)$ with six and $SU(3)$ with ten fundamental flavors are likely on the lower edge of the conformal window, which are consistent with the recent lattice results. We also predict that $Sp(4)$ theories with fundamental and antisymmetric fermions have the critical numbers of flavors, approximately ten and five, respectively.

    hep-phhep-lathep-thPRD(2021)·30 citations
15. 15*

    Triple-X and beyond: hadronic systems of three and more X(3872)

    Lorenzo Contessi🇫🇷 · Johannes Kirscher🇬🇧 · Manuel Pavon Valderrama🇨🇳

    The $X(3872)$ resonance has been conjectured to be a $J^{PC}=1^{++}$ charm meson-antimeson two-body molecule. Meanwhile, there is no experimental evidence for larger, few-body compounds of multiple charm meson-antimeson pairs which would resemble larger molecules or nuclei. Here, we investigate such multi-meson states to the extent of what can be deduced theoretically from essentials of the interaction between uncharged $D^0$ and $D^{\ast 0}$ mesons. From a molecular $X(3872)$, we predict a $4X$ ($4^{++}$) octamer with a binding energy \mbox{$B_{4X}>2.08\mathrm{MeV}$,} assuming a $D^{\ast 0}{\bar{D}}^0$ system close to the unitary limit (as suggested by the mass of the $X(3872)$). If we consider heavy-quark spin symmetry explicitly, the $D^{\ast 0}{\bar{D}}^{\ast 0}$ ($2^{++}$) system is close to unitarity, too. In this case, we predict a bound $3X$ ($3^{++}$) hexamer with $B_{3X}>2.29\mathrm{MeV}$ and a more deeply bound $4X$ octamer with $B_{4X}>11.21\mathrm{MeV}$. These results exemplify with hadronic molecules a more general phenomenon of equal-mass two-species Bose systems comprised of equal number of either type: the emergence of unbound four- and six-boson clusters in the limit of a short-range two-body interaction which acts only between bosons of different species. Finally, we also study the conditions under which a $2X$ ($2^{++}$) tetramer might form.

    hep-phnucl-thPRD(2021)·4 citations
16. 16*

    Exploring $0\nu \beta \beta$ and Leptogenesis in the Alternative Left-Right Model

    Mariana Frank🇨🇦 · Chayan Majumdar🇮🇳 · P. Poulose🇮🇳 · Supriya Senapati🇮🇳 · Urjit A. Yajnik🇮🇳

    We investigate the possibility of neutrinoless double beta decay ($0\nu \beta \beta$) and leptogenesis within the Alternative Left-Right Model (ALRM). Unlike the usual left-right symmetric model, ALRM features a Majorana right-handed neutrino which does not carry any charge. Further, in this picture the down-type quark and the charged leptons receive mass through the additional left-handed scalar field, rather than the usual doublet. Together, these features conspire to generate significant contributions to the $0\nu \beta \beta$ through vector-scalar ($WH$) mediation. For moderate masses of the relevant charged Higgs boson ($M_{H_1^{\pm }}\sim 200$ GeV), the half-life of $T_{\frac{1}{2}}^{WH}$ is $\sim 3\times 10^{26}\mathrm{yrs}$ for both the case of ${}^{76}$Ge and ${}^{136}$Xe, well within the sensitivity expected by future experiments. Invoking the resonant leptogenesis, CP violation arising from the right-handed neutrino decay could be the required order to generate the correct baryogenesis, $ϵ\sim 10^{-6}$, for small Dirac phases and without any fine tuning.

    hep-phPRD(2020)·14 citations
17. 17*

    Dark Matter from 't Hooft Anomaly Matching

    Michele Redi🇮🇹

    Light fermions that arise as composite states in confining gauge theories are stable due to fermion number conservation. This leads to Dark Matter candidates that behave similarly to elementary DM but where the cosmological stability arises automatically from the accidental symmetries of the theory. We present explicit models based on 't Hooft anomaly matching conditions where DM is charged under the SM. For example an SU(N) gauge theory with fermions in the adjoint rep and triplet of SU(2)${}_L$ gives rise to DM made of multiple "Wino" triplets, while SO(N) gauge theories with $N_F=N-4$ flavors produce neutralino-like systems or SM quintuplets. Compositeness effects are crucial to determine the phenomenology.

    hep-phastro-ph.COhep-thPRD(2021)·2 citations
18. 18*

    Locally finite two-loop amplitudes for off-shell multi-photon production in electron-positron annihilation

    Charalampos Anastasiou🇨🇭 · Rayan Haindl🇨🇭 · George Sterman🇺🇸 · Zhou Yang🇨🇳 · Mao Zeng🇨🇭

    We study the singularity structure of two-loop QED amplitudes for the production of multiple off-shell photons in massless electron-positron annihilation and develop counterterms that remove their infrared and ultraviolet divergences point by point in the loop integrand. The remainders of the subtraction are integrable in four dimensions and can be computed in the future with numerical integration. The counterterms capture the divergences of the amplitudes and factorize in terms of the Born amplitude and the finite remainder of the one-loop amplitude. They consist of simple one- and two-loop integrals with at most three external momenta and can be integrated analytically in a simple manner with established methods. We uncover novel aspects of fully local IR factorization, where vertex and self-energy subdiagrams must be modified by new symmetrizations over loop momenta, in order to expose their tree-like tensor structures and hence factorization of IR singularities prior to loop integration. This work is a first step towards isolating locally the hard contributions of generic gauge theory amplitudes and rendering them integrable in exactly four dimensions with numerical methods.

    hep-phhep-thJHEP(2021)·49 citations
19. 19*

    Parton distribution functions

    Stefano Forte🇮🇹 · Stefano Carrazza🇮🇹

    We discuss the determination of the parton substructure of hadrons by casting it as a peculiar form of pattern recognition problem in which the pattern is a probability distribution, and we present the way this problem has been tackled and solved. Specifically, we review the NNPDF approach to PDF determination, which is based on the combination of a Monte Carlo approach with neural networks as basic underlying interpolators. We discuss the current NNPDF methodology, based on genetic minimization, and its validation through closure testing. We then present recent developments in which a hyperoptimized deep-learning framework for PDF determination is being developed, optimized, and tested.

    hep-phhep-ex30 citations
20. 20*

    Gravitational Waves From Dark Sectors, Oscillating Inflatons, and Mass Boosted Dark Matter

    Amit Bhoonah🇨🇦 · Joseph Bramante🇨🇦 · Simran Nerval🇨🇦 · Ningqiang Song🇨🇦

    Gravitational waves signatures from dynamical scalar field configurations provide a compelling observational window on the early universe. Here we identify intriguing connections between dark matter and scalars fields that emit gravitational waves, either through a first order phase transition or oscillating after inflation. To study gravitational waves from first order phase transitions, we investigate a simplified model consisting of a heavy scalar coupled to a vector and fermion field. We then compute gravitational wave spectra sourced by inflaton field configurations oscillating after E-Model and T-Model inflation. Some of these gravitational wave signatures can be uncovered by the future Big Bang Observatory, although in general we find that MHz-GHz frequency gravitational wave sensitivity will be critical for discovering the heaviest dark sectors. Intriguingly, we find that scalars undergoing phase transitions, along with E-Model and T-Model potentials, can impel a late-time dark matter mass boost and generate up to Planck mass dark matter. For phase transitions and oscillating inflatons, the largest dark matter mass boosts correspond to higher amplitude stochastic gravitational wave backgrounds.

    hep-phastro-ph.COJCAP(2021)·23 citations
21. 21*

    Learning about the QCD medium using electromagnetic and weak probes

    Gojko Vujanovic🇺🇸

    Recent theoretical developments concerning radiation of electromagnetic and weak probes in ultra-relativistic heavy-ion collisions is overviewed. These proceedings focus on electromagnetic probes and briefly cover weak probes. An outlook regarding the future use of electromagnetic probes is formulated whereby a quantitative Bayesian comparison, simultaneously employing electromagnetic and hadronic calculations of experimental observables against data, is highlighted as a path towards a better understanding of the properties of the QCD medium.

    ↳ nucl-thhep-phnucl-exPoS(2021)·0 citations
22. 22*

    Elastic and Inelastic Scattering of Cosmic-Rays on Sub-GeV Dark Matter

    Gang Guo🇹🇼 · Yue-Lin Sming Tsai🇨🇳 · Meng-Ru Wu🇹🇼 · Qiang Yuan🇨🇳

    We revisit the signatures from collisions of cosmic-rays on sub-GeV dark matter (DM) in the Milky Way. In addition to the upscattered DM component that can be probed by existing DM and neutrino experiments widely discussed, we examine the associated signals in $\gamma$-rays and neutrinos that span a wide energy range due to the inelastic scatterings. Assuming a simple vector portal DM model for illustration, we compute both the upscattered DM flux by cosmic-ray protons, and the resulting emission of secondary $\gamma$-rays and high-energy neutrinos from proton excitation, hadronization, and the subsequent meson decay. We derive limits on coupling constants in the vector portal model using data from the $\gamma$-ray and high-energy neutrino telescopes including Fermi, H.E.S.S. and IceCube. These limits are compared to those obtained by considering the upscattered DM signals at the low-energy DM/neutrino detectors XENON1T/MiniBooNE and the IceCube. For this particular model, the limits are set predominantly by non-detection of the upscattered DM events in XENON1T, for most of the DM mass range due to the large scattering cross section at low energies. Nevertheless, our study demonstrates that the $\gamma$-ray and neutrino signals, traditionally considered as indirect probes for DM annihilation and decay, can also be directly used to constrain the DM--nucleon interaction in complementary to the direct search experiments.

    ↳ astro-ph.HEhep-phPRD(2020)·71 citations
23. 23*

    Backgrounds in gravitational effective field theory

    Alan Kostelecky🇺🇸 · Zonghao Li🇺🇸

    Effective field theories describing gravity coupled to matter are investigated, allowing for operators of arbitrary mass dimension. Terms violating local Lorentz and diffeomorphism invariance while preserving internal gauge symmetries are included. The theoretical framework for violations of local Lorentz and diffeomorphism invariance and associated conceptual issues are discussed, including transformations in curved and approximately flat spacetimes, the treatment of various types of backgrounds, the implications of symmetry breaking, and the no-go constraints for explicit violation in Riemann geometry. Techniques are presented for the construction of effective operators, and the possible terms in the gravity, gauge, fermion, and scalar sectors are classified and enumerated. Explicit expressions are obtained for terms containing operators of mass dimension six or less in the effective action for General Relativity coupled to the Standard Model of particle physics. Special cases considered include Einstein-Maxwell effective field theories and the limit with only scalar coupling constants.

    ↳ gr-qchep-phPRD(2021)·140 citations
24. 24*

    Hybrid static potentials in SU(2) lattice gauge theory at short quark-antiquark separations

    Carolin Riehl🇩🇪 · Marc Wagner🇩🇪

    We compute hybrid static potentials in SU(2) lattice gauge theory using a multilevel algorithm and three different small lattice spacings. The resulting static potentials, which are valid for quark-antiquark separations as small as 0.05 fm, are important e.g. when computing masses of heavy hybrid mesons in the Born-Oppenheimer approximation. We also discuss and exclude possible systematic errors from topological freezing, the finite lattice volume and glueball decays.

    ↳ hep-lathep-ph3 citations
25. 25*

    Analytic solutions of scalar perturbations induced by scalar perturbations

    Keisuke Inomata🇯🇵

    We study scalar perturbations induced by scalar perturbations through the non-linear interaction appearing at second order in perturbations. We derive analytic solutions of the induced scalar perturbations in a perfect fluid. In particular, we consider the perturbations in a radiation-dominated era and a matter-dominated era. With the analytic solutions, we also discuss the power spectra of the induced perturbations.

    ↳ gr-qcastro-ph.COhep-phJCAP(2021)·27 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.