Fri·Jul 10, 2020Friday·July 10, 2020

1. 01*

   Heavy Dark Matter, Neutrino Masses and Higgs Naturalness from a Strongly Interacting Hidden Sector

   Mayumi Aoki🇯🇵 · Vedran Brdar🇩🇪 · Jisuke Kubo🇩🇪

   We consider the extension of the Standard Model (SM) with a strongly interacting QCD-like hidden sector, at least two generations of right-handed neutrinos and one scalar singlet. Once scalar singlet obtains a nonzero vacuum expectation value, active neutrino masses are generated through type-I seesaw mechanism. Simultaneously, the electroweak scale is generated through the radiative corrections involving these massive fermions. This is the essence of the scenario that is known as the "neutrino option" for which the successful masses of right-handed neutrinos are in the range $10^7-10^8$ GeV. The main goal of this work is to scrutinize the potential to accommodate dark matter in such a realization. The dark matter candidates are Nambu-Goldstone bosons which appear due to the dynamical breaking of the hidden chiral symmetry. The mass spectrum studied in this work is such that masses of Nambu-Goldstone bosons and singlet scalar exceed those of right-handed neutrinos. Having the masses of all relevant particles several orders of magnitude above $\mathcal{O}$(TeV), the freeze-out of dark matter is not achievable and hence we turn to alternative scenarios, namely freeze-in. The Nambu-Goldstone bosons can interact with particles that are not in SM but, however, have non-negligible abundance through their not-too-small couplings with SM. Utilizing this, we demonstrate that the dark matter in the model is successfully produced at temperature scale where the right-handed neutrinos are still stable. We note that the lepton number asymmetry sufficient for the generation of observable baryon asymmetry of the Universe can be produced in right-handed neutrino decays. Hence, we infer that the model has the potential to simultaneously address several of the most relevant puzzles in contemporary high-energy physics.

   hep-phhep-thPRD(2020)·12 citations
2. 02*

   $B$ anomalies under the lens of electroweak precision

   Lina Alasfar🇩🇪 · Aleksandr Azatov🇮🇹 · Jorge de Blas🇬🇧 · Ayan Paul🇩🇪 · Mauro Valli🇺🇸

   The measurements carried out at LEP and SLC projected us into the precision era of electroweak physics. This has also been relevant in the theoretical interpretation of LHCb and Belle measurements of rare $B$ semileptonic decays, paving the road for new physics with the inference of lepton universality violation in $R_{K^{(\ast )}}$ ratios. The simplest explanation of these flavour anomalies -- sizeable one-loop contributions respecting Minimal Flavour Violation -- is currently disfavoured by electroweak precision data. In this work, we discuss how to completely relieve the present tension between electroweak constraints and one-loop minimal flavour violating solutions to $R_{K^{(\ast )}}$. We determine the correlations in the Standard Model Effective Field Theory that highlight the existence of such a possibility. Then, we consider minimal extensions of the Standard Model where our effective-field-theory picture can be realized. We discuss how these solutions to $b\to s\ell \ell$ anomalies, respecting electroweak precision and without any new source of flavour violation, may point to the existence of a $Z^{\prime }$ boson at around the TeV scale, within the discovery potential of LHC, or to leptoquark scenarios.

   hep-phhep-exJHEP(2020)·27 citations
3. 03*

   ${\eta }_c$-nucleus bound states

   J. J. Cobos-Martínez🇲🇽 · K. Tsushima🇧🇷 · G. Krein🇧🇷 · A. W. Thomas🇦🇺

   ${\eta }_c$-nucleus bound state energies are calculated for various nuclei. Essential input for the calculations, namely the medium-modified $D$ and $D^{\ast }$ meson masses, as well as the density distributions in nuclei, are calculated within the quark-meson coupling (QMC) model. The attractive potentials for the ${\eta }_c$ meson in the nuclear medium originate from the in-medium enhanced $D{D}^{\ast }$ loops in the ${\eta }_c$ self-energy. Our results suggest that the ${\eta }_c$ meson should form bound states with all the nuclei considered.

   hep-phPLB(2020)·25 citations
4. 04*

   Density dependent quark mass model revisited: Thermodynamic consistency, stability windows and stellar properties

   B. C. Backes🇧🇷 · E. Hafemann🇧🇷 · I. Marzolla🇧🇷 · D. P. Menezes🇧🇷

   In this work a density dependent quark model is revisited, its thermodynamic consistency checked and the stability window for absolutely stable quark matter obtained. The hypotheses of both pure quark matter with equal quark chemical potentials and stellar matter subject to chemical stability and charge neutrality are investigated. The parameters that appear in the density dependent mass and satisfy the Bodmer-Witten conjecture are then used to compute the masses and radii of strange stars. We show that the obtained values are compatible with the recently observed massive stars.

   hep-phastro-ph.HEnucl-thJ.Phys.G(2021)·34 citations
5. 05*

   Bayesian Neural Networks for Fast SUSY Predictions

   Braden Kronheim🇺🇸 · Michelle Kuchera🇺🇸 · Harrison Prosper🇺🇸 · Alexander Karbo🇺🇸

   One of the goals of current particle physics research is to obtain evidence for new physics, that is, physics beyond the Standard Model (BSM), at accelerators such as the Large Hadron Collider (LHC) at CERN. The searches for new physics are often guided by BSM theories that depend on many unknown parameters, which, in some cases, makes testing their predictions difficult. In this paper, machine learning is used to model the mapping from the parameter space of the phenomenological Minimal Supersymmetric Standard Model (pMSSM), a BSM theory with 19 free parameters, to some of its predictions. Bayesian neural networks are used to predict cross sections for arbitrary pMSSM parameter points, the mass of the associated lightest neutral Higgs boson, and the theoretical viability of the parameter points. All three quantities are modeled with average percent errors of 3.34% or less and in a time significantly shorter than is possible with the supersymmetry codes from which the results are derived. These results are a further demonstration of the potential for machine learning to model accurately the mapping from the high dimensional spaces of BSM theories to their predictions.

   hep-phcs.LGphysics.comp-phPLB(2021)·23 citations
6. 06*

   Searching for Boosted Dark Matter mediated by a new Gauge Boson

   Wonsub Cho🇰🇷 · Ki-Young Choi🇰🇷 · Seong Moon Yoo🇰🇷

   We study the possibility to directly detect the boosted dark matter generated from the scatterings with high energetic cosmic particles such as protons and electrons. As a concrete example, we consider the sub-GeV dark matter mediated by a $U(1{)}_D$ gauge boson which has mixing with $U(1{)}_Y$ gauge boson in the standard model. The enhanced kinetic energy of the light dark matter from the collision with the cosmic rays can recoil the target nucleus and electron in the underground direct detection experiments transferring enough energy to them to be detectable. We show the impact of BDM with existing direct detection experiments as well as collider and beam-dump experiments.

   hep-phastro-ph.HEPRD(2020)·31 citations
7. 07*

   Top quark pair production in the exclusive processes at LHC

   Victor P. Goncalves🇧🇷 · Daniel E. Martins🇧🇷 · Murilo S. Rangel🇧🇷 · Marek Tasevsky🇨🇿

   We analyze the LHC prospects for measurements of the $t\bar{t}$ pair produced exclusively in photon-photon or semi-exclusively in photon-Pomeron and Pomeron-Pomeron processes using protons tagged in forward proton detectors on both sides of the interaction point. These processes are interesting from the point of view of a possible measurement of the top quark mass and constraining models used in Beyond Standard Model physics. Focusing on the semi-leptonic channel, $t\bar{t}\to jjbl{\nu }_l\bar{b}$, making use of the exclusive nature of the final state, together with the use of timing information provided by forward proton detectors, relevant exclusive and inclusive backgrounds are studied in detail for different luminosity (or pile-up) scenarios and found to be important for further considerations. While good prospects are found for observing the signal, the top quark mass measurement turns out not to be competitive with measurements in inclusive channels.

   hep-phPRD(2020)·34 citations
8. 08*

   The Relativistic Corrections of GPS

   Takeshi Fukuyama🇯🇵 · Sueo Sugimoto🇯🇵

   We calculate the special and general relativistic effects of the Global Positioning System (GPS), especially the effects depending on the small deviation of the orbit from the circular one. This effect is well known but, to our knowledge, the detail of its derivation is not known publicly. GPS is widely used in particle physics experiments and this letter may be useful among this community.

   hep-ph1 citation
9. 09*

   On Preheating in Higgs Inflation

   Yuta Hamada🇫🇷 · Kiyoharu Kawana🇯🇵 · Adam Scherlis🇺🇸

   Recently, the problem of unitarity violation during the preheating stage of Higgs inflation with a large non-minimal coupling has been much discussed in the literature. We point out that this problem can be translated into a strong coupling problem for the dimensionless effective coupling, and that the existence of these problems is highly dependent on the choice of higher-dimensional operators because they can significantly change the background dynamics and the canonical normalization of the fluctuations around it. Correspondingly, the typical energy of particles produced during the first stage of preheating can remain comparable to or below the cutoff scale of the theory. As an example, we numerically calculate the particle production in the presence of a specific four-derivative operator of the Higgs field, and confirm the statement above. Our argument also applies to multi-field inflation with non-minimal couplings.

   hep-phgr-qchep-thJCAP(2021)·35 citations
10. 10*

    Exploring the centrality dependence of elliptic and triangular flows

    V.L. Korotkikh🇷🇺 · A.M. Snigirev🇷🇺

    A detailed study of elliptical and triangular eccentricities in the initial state of relativistic heavy ion collisions is presented. A model of randomly distributed sources of energy density in the transverse plane based on the effective theory of Color Glass Condensate is used. This model describes well the ALICE and ATLAS data for Pb+Pb collisions at center-of-mass energy 5.02 TeV per nucleon pair in a wide range of centralities, if the second $v_2$ and third $v_3$ harmonics of the anisotropic flow are simply implied to be proportional to the eccentricities ${\epsilon }_2$ and ${\epsilon }_3$ as a reasonable approximation. The eccentricity ${\epsilon }_2$ is closely related with the collision geometry and its centrality dependence is mainly determined by the edge diffuseness of the region of the uniform distribution of the saturation pulse of the oncoming nucleus. The eccentricity ${\epsilon }_3$ is completely determined by the chaotic fluctuations of the source position in the region of overlapping nuclei and is substantially dependent on the overlap area only.

    hep-phnucl-exnucl-th0 citations
11. 11*

    Strong CP violation in nuclear physics

    Jordy de Vries🇺🇸 · Alex Gnech🇮🇹 · Sachin Shain🇺🇸

    Electric dipole moments of nuclei, diamagnetic atoms, and certain molecules are induced by CP-violating nuclear forces. Naive dimensional analysis predicts these forces to be dominated by long-range one-pion-exchange processes, with short-range forces entering only at next-to-next-to-leading order in the chiral expansion. Based on renormalization arguments we argue that a consistent picture of CP-violating nuclear forces requires a leading-order short-distance operator contributing to ${}^1{S}_0$-${}^3{P}_0$ transitions, due to the attractive and singular nature of the strong tensor force in the ${}^3{P}_0$ channel. The short-distance operator leads to $\mathcal{O}(1)$ corrections to static and oscillating, relevant for axion searches, electric dipole moments. We discuss strategies how the finite part of the associated low-energy constant can be determined in the case of CP violation from the QCD theta term by the connection to charge-symmetry violation in nuclear systems.

    hep-phnucl-thPRC(2021)·21 citations
12. 12*

    Forward-backward multiplicity and momentum correlations in $pp$ collisions at LHC energies

    Mitali Mondal🇮🇳 · Joyati Mondal🇮🇳 · Somnath Kar🇮🇳 · Argha Deb🇮🇳 · Premomoy Ghosh🇮🇳

    Charged-particle multiplicity and summed values of the transverse momentum ($p_{\mathrm{T}}$) have been utilized for estimating forward-backward (FB) correlation strength for EPOS3 simulated proton-proton ($pp$) events with and without hydrodynamical evolution of particles at center-of-mass energies $\sqrt{s}$ = 0.9, 2.76, and 7 TeV for different pseudorapidity window width ($\delta \eta$) and gap (${\eta }_{gap}$) between the FB windows. We have studied the variation of FB correlation strength with ${\eta }_{gap}$, $\delta \eta$, $\sqrt{s}$, $p_{\mathrm{T}}$ cuts and multiplicity classes. Results are compared with the corresponding ALICE and ATLAS data. EPOS3 model qualitatively reproduces the overall variation of correlation strength of the LHC data. However, quantitative agreement is better for $pp$ events, generated using EPOS3 with hydrodynamical evolution of particles, with ATLAS data.

    hep-phPRD(2020)·17 citations
13. 13*

    EFT Approach of Inelastic Dark Matter for Xenon Electron Recoil Detection

    Hong-Jian He🇨🇳 · Yu-Chen Wang🇨🇳 · Jiaming Zheng🇨🇳

    Measuring dark matter (DM) signals via electron recoil provides an important means for direct detection of light DM particles. The recent XENON1T anomaly with electron recoil energy around $E_R^{}=(2-3)$keV can be naturally explained by DM inelastic scattering which injects energy to the recoiled electrons and gives a narrow peak structure in the recoil spectrum. We present an effective field theory (EFT) approach to exothermic inelastic DM signals for the Xenon electron recoil detection. For relatively heavy mediator, we fairly formulate the DM-lepton interactions by effective contact operators with two DM fields $(X,X^{\prime })$ and two leptons. Using the XENON1T data, we fit the electron recoil spectrum and constrain the allowed scalar DM mass-splitting as $2.1\text{keV}<\Delta m<3.3\text{keV}$ (95%C.L.), with the best fit $\Delta m=2.8$keV. We analyze the relic abundance produced by such effective DM-electron contact interaction. To provide both the DM relic abundance and the XENON1T excess, we derive new constraints on the DM mass and the UV cutoff scale of DM effective interactions. Finally, we study possible UV completions for the effective DM-lepton contact interactions.

    hep-phastro-ph.COhep-exJCAP(2021)·36 citations
14. 14*

    An Attractive Scenario for Light Dark Matter Direct Detection

    Hooman Davoudiasl🇺🇸 · Peter B. Denton🇺🇸 · Julia Gehrlein🇺🇸

    Direct detection of light dark matter (DM), below the GeV scale, through electron recoil can be efficient if DM has a velocity well above the virial value of $v\sim 10^{-3}$. We point out that if there is a long range attractive force sourced by bulk ordinary matter, i.e. baryons or electrons, DM can be accelerated towards the Earth and reach velocities $v\sim 0.1$ near the Earth's surface. In this "attractive scenario," all DM will be boosted to high velocities by the time it reaches direct detection apparatuses in laboratories. Furthermore, the attractive force leads to an enhanced DM number density at the Earth facilitating DM detection even more. We elucidate the implications of this scenario for electron recoil direct detection experiments and find parameters that could lead to potential signals, while being consistent with stellar cooling and other bounds. Our scenario can potentially explain the recent excess in electron recoil signals reported by the XENON1T experiment in the $\sim$ keV energy regime as well as the hint for non-standard stellar cooling.

    hep-phhep-exPRD(2020)·18 citations
15. 15*

    More Axions from Strings

    Marco Gorghetto🇮🇱 · Edward Hardy🇬🇧 · Giovanni Villadoro🇮🇹

    We study the contribution to the QCD axion dark matter abundance that is produced by string defects during the so-called scaling regime. Clear evidence of scaling violations is found, the most conservative extrapolation of which strongly suggests a large number of axions from strings. In this regime, nonlinearities at around the QCD scale are shown to play an important role in determining the final abundance. The overall result is a lower bound on the QCD axion mass in the post-inflationary scenario that is substantially stronger than the naive one from misalignment.

    hep-phastro-ph.COhep-thSciPost Phys.(2021)·368 citations
16. 16*

    Relaxing Cosmological Neutrino Mass Bounds with Unstable Neutrinos

    Miguel Escudero🇬🇧 · Jacobo Lopez-Pavon🇪🇸 · Nuria Rius🇪🇸 · Stefan Sandner🇪🇸

    At present, cosmological observations set the most stringent bound on the neutrino mass scale. Within the standard cosmological model ($\Lambda$CDM), the Planck collaboration reports $\sum m_{\nu }<0.12\text{eV}$ at 95% CL. This bound, taken at face value, excludes many neutrino mass models. However, unstable neutrinos, with lifetimes shorter than the age of the universe ${\tau }_{\nu }\lesssim t_U$, represent a particle physics avenue to relax this constraint. Motivated by this fact, we present a taxonomy of neutrino decay modes, categorizing them in terms of particle content and final decay products. Taking into account the relevant phenomenological bounds, our analysis shows that 2-body decaying neutrinos into BSM particles are a promising option to relax cosmological neutrino mass bounds. We then build a simple extension of the type I seesaw scenario by adding one sterile state ${\nu }_4$ and a Goldstone boson $\varphi$, in which ${\nu }_i\to {\nu }_4\varphi$ decays can loosen the neutrino mass bounds up to $\sum m_{\nu }\sim 1\text{eV}$, without spoiling the light neutrino mass generation mechanism. Remarkably, this is possible for a large range of the right-handed neutrino masses, from the electroweak up to the GUT scale. We successfully implement this idea in the context of minimal neutrino mass models based on a $U(1{)}_{\mu -\tau }$ flavor symmetry, which are otherwise in tension with the current bound on $\sum m_{\nu }$.

    hep-phastro-ph.COhep-exJHEP(2020)·100 citations
17. 17*

    Lepton universality and lepton flavor conservation tests with dineutrino modes

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

    $SU(2{)}_L$-invariance links charged dilepton and dineutrino couplings. Phenomenological implications are worked out for flavor changing neutral currents involving strange, charm, beauty and top quark transitions in a model-independent way. We put forward novel tests of lepton universality and lepton flavor conservation in $|\Delta c|=|\Delta u|=1$ and $|\Delta b|=|\Delta q|=1$, $q=d,s$, transitions suitable for the experiments Belle II and BES III. Single top production plus dileptons uniquely probes semileptonic four-fermion $|\Delta t|=|\Delta q^{\prime }|=1$, $q^{\prime }=u,c$, couplings and further study at the LHC is encouraged. Tests with single top production associated with dileptons and missing energy are suitable for study at future $e^{+}{e}^{-}$ or muon colliders.

    hep-phhep-exEPJC(2022)·49 citations
18. 18*

    Higgs sector phenomenology in the 3-3-1 model with an axionlike particle

    V.H. Binh (GUST, Hanoi and Hanoi, Inst. Phys.)🇻🇳 · D.T. Binh (Duy Tan U.)🇻🇳 · A.E. Cárcamo Hernández (Santa Maria U. Valparaiso and Millenium Inst. Astro., Santiago)🇨🇱 · D.T. Huong (Hanoi, Inst. Phys.)🇻🇳 · D.V. Soa (Hanoi UNETI)🇻🇳 · H.N. Long (Van Lang U.)🇻🇳

    The scalar sector of the 3-3-1 model with axion like particle is studied in detail. In the model under consideration, there are two kinds of scalar fields: the bilepton scalars carrying lepton number two and the ordinary ones without lepton number. We show that there is no mixing among these two kinds of scalar fields. We analyze in detail the CP-odd scalar sector of the model to find the physical fields of the axion like particle and a pseudoscalar with mass in the range 100 GeV to 1 TeV. The results are different from others which have been published before. The CP-even scalar sector of the model is analyzed as well. The results of our analysis of the scalar sector allow us to accommodate scalar masses in the $100$ GeV-$1$ TeV region. Furthermore we analyze the implications of the model in several flavor changing neutral decays of the top quark as well as in rare top quark decays. Besides that, the leptonic decays of the SM like Higgs boson as well as the meson oscillations are also analyzed. Our numerical analysis show that the model under consideration is consistent with the experimental constraints imposed by these processes.

    hep-phPRD(2023)·18 citations
19. 19*

    Masses, Radii and Regge Trajectories of ${\Sigma }_u^{-}$ State Hybrid Charmonium

    Nosheen Akbar🇵🇰

    In this paper, masses and radii of ${\Sigma }_u^{-}$ states hybrid charmonium mesons are calculated by numerically solving the Schrödinger equation with non-relativistic potential model. Results for calculated masses of ${\Sigma }_u^{-}$ states charmonium hybrid mesons are found to be close to the results obtained through lattice simulations. Calculated masses are used to construct Regge trajectories. It is found that the trajectories are almost linear and parallel.

    hep-phFew Body Syst.(2022)·1 citation
20. 20*

    Tree-level splitting amplitudes for a gluon into four collinear partons

    Vittorio Del Duca🇨🇭 · Claude Duhr🇨🇭 · Rayan Haindl🇨🇭 · Achilleas Lazopoulos🇨🇭 · Martin Michel🇧🇪

    We compute in conventional dimensional regularisation the tree-level splitting amplitudes for a gluon parent which splits into four collinear partons. This is part of the universal infrared behaviour of the QCD scattering amplitudes at next- to-next-to-next-to-leading order (N${}^3$LO) in the strong coupling constant. Combined with our earlier results for a quark parent, this completes the set of tree-level splitting amplitudes required at this order. We also study iterated collinear limits where a subset of the four collinear partons become themselves collinear.

    hep-phJHEP(2020)·39 citations
21. 21*

    Hydrodynamics of simply spinning black holes & hydrodynamics for spinning quantum fluids

    Markus Garbiso🇺🇸 · Matthias Kaminski🇺🇸

    We find hydrodynamic behavior in large simply spinning five-dimensional Anti-de Sitter black holes. These are dual to spinning quantum fluids through the AdS/CFT correspondence constructed from string theory. Due to the spatial anisotropy introduced by the angular momentum in the system, hydrodynamic transport coefficients split into one group longitudinal and another transverse to the angular momentum. Analytic expressions are provided for the two shear viscosities, the longitudinal momentum diffusion coefficient, two speeds of sound, and two sound attenuation coefficients. Known relations between these coefficients are generalized to include dependence on angular momentum. The shear viscosity to entropy density ratio varies between zero and 1/(4$\pi$) depending on the direction of the shear. These results can be applied to heavy ion collisions, in which the most vortical fluid was reported recently. In passing, we show that large simply spinning five-dimensional Myers-Perry black holes are perturbatively stable for all angular momenta below extremality.

    ↳ hep-thhep-phnucl-thJHEP(2020)·85 citations
22. 22*

    Myth of scattering in finite volume

    Peng Guo🇺🇸

    In this notes, we illustrate why the infinite volume scattering amplitude is in fact dispensable when it comes to formulating few-body quantization condition in finite volume. Only subprocess interactions or interactions associated subprocess amplitudes are essential and fundamental ingredients of quantization conditions. After these ingredients are determined, infinite volume scattering amplitude can be computed separately. The underlying reasons are rooted in facts that (1) the final physical process is generated by all subprocess or interactions among particles; (2) the ultimate goal of quantization condition in finite volume is to find stationary solutions of few-body system. That is to say, in the end, it all comes down to the solving of eigenvalue problem, $\hat{H}|n⟩=E_n|n⟩$.

    ↳ hep-lathep-phnucl-th10 citations
23. 23*

    Broadband X-ray characteristics of the transient pulsar GRO J2058+42

    Sanhita Kabiraj🇮🇳 · Biswajit Paul🇮🇳

    The Be X-ray binary GRO J2058+42 recently went through a Type-II outburst during March-April 2019 lasting for about 50 days. This outburst was detected with the operating all sky X-ray monitors like the Fermi-GBM, Swift-BAT and MAXI-GSC. Two NuSTAR observations were also made, one during the rise and other during the decay of the outburst. It gave us the unique opportunity to analyze the broadband characteristics of the pulsar for the first time and accretion torque characteristics of the pulsar over a range of X-ray luminosity. The pulse profiles are strongly energy dependent, with at least four different pulse components at low energy (< 20 keV) which evolves to a single-peaked profile at high energy (> 30 keV). In each of the narrow energy bands, the pulse profiles are nearly identical in the two NuSTAR observations. The spectra from both the observations are fitted well to a power-law with a Fermi-Dirac type high energy cutoff. We ruled out presence of a cyclotron line in the pulse phase averaged X-ray spectrum in the NuSTAR band with an optical depth greater than 0.15. An iron emission line is detected in both the NuSTAR spectra with an equivalent width of about 125 eV. We looked at the dependence of the spin-up rate on the luminosity and estimated the magnetic field strength from that, which came out to be much higher compared to other known BeXRB pulsars. Lastly, we discussed the inadequacy of the torque-luminosity relation for determination of magnetic field strength of neutron stars.

    ↳ astro-ph.HEhep-phMNRAS(2020)·8 citations
24. 24*

    New Graviton Mass Bound from Binary Pulsars

    Lijing Shao🇨🇳 · Norbert Wex🇩🇪 · Shuang-Yong Zhou🇨🇳

    In Einstein's general relativity, gravity is mediated by a massless metric field. The extension of general relativity to consistently include a mass for the graviton has profound implications for gravitation and cosmology. Salient features of various massive gravity theories can be captured by Galileon models, the simplest of which is the cubic Galileon. The presence of the Galileon field leads to additional gravitational radiation in binary pulsars where the Vainshtein mechanism is less suppressed than its fifth-force counterpart, which deserves a detailed confrontation with observations. We prudently choose fourteen well-timed binary pulsars, and from their intrinsic orbital decay rates we put a new bound on the graviton mass, $m_g\lesssim 2\times 10^{-28}\mathrm{eV}/c^2$ at the 95% confidence level, assuming a flat prior on $\ln m_g$. It is equivalent to a bound on the graviton Compton wavelength ${\lambda }_g\gtrsim 7\times 10^{21}\mathrm{m}$. Furthermore, we extensively simulate times of arrival for pulsars in orbit around stellar-mass black holes and the supermassive black hole at the Galactic center, and investigate their prospects in probing the cubic Galileon theory in the near future.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·35 citations
25. 25*

    Non-Relativistic Formation of Scalar Clumps as a Candidate for Dark Matter

    Philippe Brax🇫🇷 · Jose A. R. Cembranos🇪🇸 · Patrick Valageas🇫🇷

    We propose a new mechanism for the formation of dark matter clumps in the radiation era. We assume that a light scalar field is decoupled from matter and oscillates harmonically around its vacuum expectation value. We include self-interactions and consider the nonrelativistic regime. The scalar dynamics are described by a fluid approach where the fluid pressure depends on both quantum and self-interaction effects. When the squared speed of sound of the scalar fluid becomes negative, an instability arises and the fluctuations of the scalar energy-density field start growing. They eventually become nonlinear and clumps form. Subsequently, the clumps aggregate and reach a universal regime. Afterwards, they play the role of cold dark matter. We apply this mechanism first to a model with a negative quartic term stabilised by a positive self-interaction of order six, and then to axion monodromy, where a subdominant cosine potential corrects a mass term. In the first case, the squared speed of sound becomes negative when the quartic term dominates, leading to a tachyonic instability. For axion monodromy, the instability starts very slowly after the squared speed of sound first becomes negative and then oscillates around zero. Initially the density perturbations perform acoustic oscillations due to the quantum pressure. Eventually, they start growing exponentially due to a parametric resonance. In both scenarios, the scalar-field clumps span a wide range of scales and masses, running from the size of atoms to that of galactic molecular clouds, and from $10^{-3}\mathrm{gram}$ to thousands of solar masses. Because of finite-size effects, both from the source and the lens, these dark matter clumps are far beyond the reach of microlensing observations.

    ↳ astro-ph.COgr-qchep-phPRD(2020)·17 citations
26. 26*

    Results of search for magnetized quark-nugget dark matter from radial impacts on Earth

    J. Pace VanDevender🇺🇸 · Robert G. Schmitt🇺🇸 · Niall McGinley🇮🇪 · David G. Duggan🇮🇪 · Seamus McGinty🇮🇪 · Aaron P. VanDevender🇺🇸 · Peter Wilson🇮🇪 · Deborah Dixon🇺🇸 · Helen Girard🇺🇸 · Jacquelyn McRae🇺🇸

    Magnetized Quark Nuggets (MQNs) are a recently proposed dark-matter candidate consistent with the Standard Model and with Tatsumi's theory of quark-nugget cores in magnetars. Previous publications have covered their formation in the early universe, aggregation into a broad mass distribution before they can decay by the weak force, interaction with normal matter through their magnetopause, and first observation consistent MQNs, i.e. a nearly tangential impact limiting their surface-magnetic-field parameter B_o from Tatsumi's values of 0.1 to 10.0 TT to new value of 1.65 TT +/- 21%. The MQN mass distribution and interaction cross section depend strongly on B_o. Their magnetopause is much larger than their geometric dimensions and can cause sufficient energy deposition to form non-meteorite craters, which are reported approximately annually. We report computer simulations of the MQN energy deposition in water-saturated peat, soft sediments, and granite and report results from excavating such a crater. Five points of agreement between observations and hydrodynamic simulations of an MQN impact support this second observation consistent with MQN dark matter and suggest a method for qualifying additional MQN events. The results also redundantly constrain B_o to greater than 0.4 TT.

    ↳ astro-ph.EPastro-ph.COgr-qchep-phUniverse(2021)·9 citations
27. 27*

    The full angle-dependence of the four-loop cusp anomalous dimension in QED

    Robin Brüser🇩🇪 · Christoph Dlapa🇩🇪 · Johannes M. Henn🇩🇪 · Kai Yan🇩🇪

    The angle-dependent cusp anomalous dimension governs divergences coming from soft gluon exchanges between heavy particles, such as top quarks. We focus on the matter-dependent contributions and compute the first truly non-planar terms. They appear at four loops and are proportional to a quartic Casimir operator in color space. Specializing our general gauge theory result to U(1), we obtain the full QED four-loop angle-dependent cusp anomalous dimension. While more complicated functions appear at intermediate steps, the analytic answer depends only on multiple polylogarithms with singularities at fourth roots of unity. It can be written in terms of four rational structures, and contains functions of up to maximal transcendental weight seven. Despite this complexity, we find that numerically the answer is tantalizingly close to the appropriately rescaled one-loop formula, over most of the kinematic range. We take several limits of our analytic result, which serves as a check and allows us to obtain new, power-suppressed terms. In the anti-parallel lines limit, which corresponds to production of two massive particles at threshold, we find that the subleading power correction vanishes. Finally, we compute the quartic Casimir contribution for scalars in the loop. Taking into account a supersymmetric decomposition, we derive the first non-planar corrections to the quark anti-quark potential in maximally supersymmetric gauge theory.

    ↳ hep-thhep-phPRL(2021)·24 citations
28. 28*

    Nucleon clustering at kinetic freezeout of heavy-ion collisions via path-integral Monte Carlo

    Dallas DeMartini🇺🇸 · Edward Shuryak🇺🇸

    Clustering of the four-nucleon system at kinetic freezeout conditions is studied using path-integral Monte Carlo techniques. This method seeks to improve upon previous calculations which relied on approximate semiclassical methods or few-body quantum mechanics. Estimates are given for the decay probabilities of the 4N system into various light nuclei decay channels and the strength of spatial correlations is characterized. Additionally, a simple model is presented to describe the impact of this clustering on nucleon multiplicity distributions. The effects of a possible modification of the inter-nucleon interaction due to the close critical line (and hypothetical QCD critical point) on the clustering are also studied.

    ↳ nucl-thhep-phNPA(2021)·10 citations
29. 29*

    Searching for vector dark matter with an optomechanical accelerometer

    Jack Manley🇺🇸 · Mitul Dey Chowdhury🇺🇸 · Daniel Grin🇺🇸 · Swati Singh🇺🇸 · Dalziel J. Wilson🇺🇸

    We consider using optomechanical accelerometers as resonant detectors for ultralight dark matter. As a concrete example, we describe a detector based on a silicon nitride membrane fixed to a beryllium mirror, forming an optical cavity. The use of different materials gives access to forces proportional to baryon (B) and lepton (L) charge, which are believed to be coupling channels for vector dark matter particles ("dark photons"). The cavity meanwhile provides access to quantum-limited displacement measurements. For a centimeter-scale membrane pre-cooled to 10 mK, we argue that sensitivity to vector B-L dark matter can exceed that of the Eöt-Wash experiment in integration times of minutes, over a fractional bandwidth of $\sim 0.1\%$ near 10 kHz (corresponding to a particle mass of $10^{-10}$eV/c${}^2$). Our analysis can be translated to alternative systems such as levitated particles, and suggests the possibility of a new generation of table-top experiments.

    ↳ quant-phhep-phPRL(2021)·72 citations
30. 30*

    Gravitational wave spectra from strongly supercooled phase transitions

    Marek Lewicki🇬🇧 · Ville Vaskonen🇬🇧

    We study gravitational wave (GW) production in strongly supercooled cosmological phase transitions, taking particular care of models featuring a complex scalar field with a U$(1)$ symmetric potential. We perform lattice simulations of two-bubble collisions to properly model the scalar field gradients, and compute the GW spectrum sourced by them using the thin-wall approximation in many-bubble simulations. We find that in the U$(1)$ symmetric case the low-frequency spectrum is $\propto \omega$ whereas for a real scalar field it is $\propto {\omega }^3$. In both cases the spectrum decays as ${\omega }^{-2}$ at high frequencies.

    ↳ astro-ph.COhep-phEPJC(2020)·115 citations
31. 31*

    "Non-Local" Effects from Boosted Dark Matter in Indirect Detection

    Kaustubh Agashe🇺🇸 · Steven J. Clark🇺🇸 · Bhaskar Dutta🇺🇸 · Yuhsin Tsai🇺🇸

    Indirect dark matter (DM) detection typically involves the observation of standard model (SM) particles emerging from DM annihilation/decay inside regions of high dark matter concentration. We consider an annihilation scenario in which this reaction has to be initiated by one of the DMs involved being boosted while the other is an ambient non-relativistic particle. This "trigger" DM must be created, for example, in a previous annihilation or decay of a heavier component of DM. Remarkably, boosted DM annihilating into gamma-rays at a specific point in a galaxy could actually have traveled from its source at another point in the same galaxy or even from another galaxy. Such a "non-local" behavior leads to a non-trivial dependence of the resulting photon signal on the galactic halo parameters, such as DM density and core size, encoded in the so-called "astrophysical" $J$-factor. These non-local $J$-factors are strikingly different than the usual scenario. A distinctive aspect of this model is that the signal from dwarf galaxies relative to the Milky Way tends to be suppressed from the typical value to various degrees depending on their characteristics. This feature can thus potentially alleviate the mild tension between the DM annihilation explanation of the observed excess of $\sim$ GeV photons from the Milky Way's galactic center vs. the apparent non-observation of the corresponding signal from dwarf galaxies.

    ↳ astro-ph.COhep-phPRD(2021)·10 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.