Fri·Sep 4, 2020Friday·September 4, 2020

1. 01*

   Two Component Singlet-Triplet Scalar Dark Matter and Electroweak Vacuum Stability

   Amit Dutta Banik🇨🇳 · Rishav Roshan🇮🇳 · Arunansu Sil🇮🇳

   We propose a two component dark matter set-up by extending the Standard Model with a singlet and a hypercharge-less triplet scalars, each of them being odd under different $Z_2$ symmetries. We observe that the inter-conversion between the two dark matter components allow a viable parameter space where masses of both the dark matter candidates can be below TeV, even though their individual contribution to single component dark matter rules out any such sub-TeV dark matter. We find that a lighter mass of the neutral component of the scalar triplet, playing the role of one dark matter component, compared to the scalar one is favored. In addition, the set-up is shown to make the electroweak vacuum absolutely stable till the Planck scale, thanks to Higgs portal coupling with the scalar dark matter components.

   hep-phPRD(2021)·30 citations
2. 02*

   A fully basis invariant Symmetry Map of the 2HDM

   Miguel P. Bento🇵🇹 · Rafael Boto🇵🇹 · João P. Silva🇵🇹 · Andreas Trautner🇩🇪

   We derive necessary and sufficient conditions for all global symmetries of the most general two Higgs doublet model (2HDM) scalar potential entirely in terms of reparametrization independent, i.e. basis invariant, objects. This culminates in what we call a "Symmetry Map" of the parameter space of the model and the fundamental insight that there are, in general, two algebraically distinct ways of how symmetries manifest themselves on basis invariant objects: either, basis invariant objects can be non-trivially related, or, basis covariant objects can vanish. These two options have different consequences on the resulting structure of the ring of basis invariants and on the number of remaining physical parameters. Alongside, we derive for the first time necessary and sufficient conditions for CP conservation in the 2HDM entirely in terms of CP-even quantities. This study lays the methodological foundation for analogous investigations of global symmetries in all other models that have unphysical freedom of reparametrization, most notably the Standard Model flavor sector.

   hep-phhep-thJHEP(2020)·18 citations
3. 03*

   Hyperasymptotic approximation to the plaquette and determination of the gluon condensate

   Cesar Ayala🇨🇱 · Xabier Lobregat🇪🇸 · Antonio Pineda🇪🇸

   We give the hyperasymptotic expansion of the plaquette with a precision that includes the terminant associated to the leading renormalon. Subleading effects are also considered. The perturbative series is regulated using the principal value prescription for its Borel integral. We use this analysis to give a determination of the gluon condensate in SU(3) pure gluodynamics that is independent of the scale and renormalization scheme used for the coupling constant: $⟨G^2{⟩}_{\mathrm{PV}}(n_f=0)=3.15(18)r_0^{-4}$.

   hep-phhep-lathep-thJHEP(2020)·20 citations
4. 04*

   Proton spin after 30 years: what we know and what we don't?

   Xiangdong Ji🇺🇸 · Feng Yuan🇺🇸 · Yong Zhao🇺🇸

   More than three decades has passed since the European Muon Collaboration published the first surprising result on the spin structure of the proton. Much theoretical and experimental progress has been made in understanding the origins of the proton spin. In this review, we will discuss what we have learned so far, what are still missing, and what we shall expect to learn from the upcoming experiments including JLab 12 GeV and Electron-Ion Collider. In particular, we focus on first principles calculations and experimental measurements of the total gluon helicity $\Delta G$, and quark and gluon orbital angular momenta.

   hep-phhep-exhep-latnucl-ex+1Nature Rev.Phys.(2021)·137 citations
5. 05*

   Jet fragmentation function in heavy-ion collisions

   Paul Caucal🇫🇷 · Edmond Iancu🇫🇷 · Alfred H. Mueller🇺🇸 · Gregory Soyez🇫🇷

   We study the fragmentation function of jets propagating through a dense quark-gluon plasma within perturbative QCD. Our results for its nuclear modification factor are in qualitative agreement with the experimental data in Pb+Pb collisions at the LHC. In particular, we reproduce the enhancements seen in the data at both relatively soft and relatively large transverse momenta, with clear physical interpretations. The perturbative predictions however are quite sensitive to the value of the infrared cutoff mimicking the confinement scale, due to the fact that the fragmentation function is not an infrared safe quantity. To remedy this, we propose a new observable -- the (primary) subjet fragmentation function -- which is infrared safe and has features similar to the fragmentation function. We provide predictions for this observable in the vacuum and in heavy-ion collisions that could be tested against the experimental data.

   hep-phnucl-thPoS(2021)·2 citations
6. 06*

   Searching for Supersymmetry: The $\mu \nu$SSM

   Daniel E. Lopez-Fogliani🇦🇷 · Carlos Munoz🇪🇸

   We review the role played by the '$\mu$ from $\nu$' supersymmetric standard model ($\mu \nu$SSM) in the search for supersymmetry. First, we discuss its theoretical motivation, that is the simultaneous solution of $\mu$- and $\nu$-problems through the introduction of right-handed neutrinos. The latter produces $R$-parity violation (RPV), giving rise to interesting signals of new physics. As by-products, in the $\mu \nu$SSM there are dark matter candidates, and electroweak baryogenesis can be realized. Then, we survey signals by which the model could be tested at the large hadron collider (LHC). In addition to the enlarged Higgs sector with sneutrinos, we put special emphasis in analyzing the intimate connection between the lightest supersymmetric particle (LSP) lifetime and the size of neutrino Yukawa couplings. Displaced vertices and/or multileptons are some of the interesting signatures that can be probed. Finally, we discuss possible extensions of the $\mu \nu$SSM such as the inclusion in the superpotential of the conventional trilinear lepton-number violating couplings, the addition of an extra $U(1{)}^{\prime }$ gauge group to the symmetry of the standard model, or the reinterpretation of the Higgs doublets as a fourth family of leptons superfields motivating the existence of a fourth family of vector-like quark doublet superfields.

   hep-phastro-ph.HEhep-exhep-thEur.Phys.J.ST(2020)·20 citations
7. 07*

   The $\varphi (2170)$ production in the process $\gamma p\to \eta \varphi p$

   Guan-Ying Wang🇨🇳 · Chen-Guang Zhao🇨🇳 · En Wang🇨🇳 · De-Min Li🇨🇳 · Guan-Nan Li🇨🇳

   We have studied the $\gamma p\to \eta \varphi p$ reaction within the effective Lagrangian approach, and our results show that there may be a peak, at least a bump structure around 2180 MeV associated to the resonance $\varphi (2170)$ in the $\eta \varphi$ mass distribution. We suggest to search for the resonance $\varphi (2170)$ in this reaction, which would be helpful to shed light on its nature.

   hep-phHadron Spectroscopy and Structure, pp. 12…·0 citations
8. 08*

   Canonical interpretation of the $X(4140)$ state within the ${}^3{P}_0$ model

   Wei Hao🇨🇳 · Guan-Ying Wang🇨🇳 · En Wang🇨🇳 · De-Min Li🇨🇳 · Guan-Nan Li🇨🇳

   Recently, LHCb collaboration has confirmed the state $X(4140)$, with a much larger width $\Gamma =83\pm 21_{-14}^{+21}$ MeV than the previous experimental measurements, which has confused the understanding of its nature. We have investigated the possibility of the ${\chi }_{c1}(3P)$ interpretation for the $X(4140)$, considering the mass and the strong decay properties.

   hep-phHadron Spectroscopy and Structure, pp. 77…·0 citations
9. 09*

   The role of $X(4140)$ and $X(4160)$ in the reactions of $B^{+}\to J/\psi \varphi K^{+}$

   En Wang🇨🇳 · Ju-Jun Xie🇨🇳 · Li-Sheng Geng🇨🇳 · Eulogio Oset🇪🇸

   We have studied the $J/\psi \varphi$ mass distribution of the process $B^{+}\to J/\psi \varphi K^{+}$ from the threshold to about 4250 MeV, by considering the contribution of the $X(4140)$ with a narrow width, together with the $X(4160)$ state. Our results show that the cusp structure at the $D_s^{\ast }{\bar{D}}_s^{\ast }$ threshold is tied to the molecular nature of the $X(4160)$ state.

   hep-phHadron Spectroscopy and Structure, pp. 12…·0 citations
10. 10*

    A Tale of Two-U(1) Axion Models

    Dong Hu🇨🇳 · Hao-Ran Jiang🇨🇳 · Hao-Lin Li🇨🇳 · Ming-Lei Xiao🇨🇳 · Jiang-Hao Yu🇨🇳

    The $U(1)$ global symmetry to solve the strong $CP$ problem could be the remnant of multi-$U(1)$ symmetries from QCD and hidden strong dynamics. Both Peccei-Quinn $U(1)$ and dynamical $U(1)$ are described uniformly, based on which we classify various mixed two-$U(1)$ models to solve both strong $CP$ and quality problems. We propose a moose diagram method with different fermion assignments to directly read relations between $CP$ phases, which illustrate how strong $CP$ problem is solved in terms of cancellation between $CP$ phases. In two axion models, we find the lightest axion is still same as QCD axion at infrared region, while one axion model with $Z_2$ symmetry enhances the axion mass spectrum. Our discussions can be extended to multi-axion cases.

    hep-phPRD(2021)·6 citations
11. 11*

    Challenge to Anomalous Phenomena in Solar Neutrino

    Y. H. Ahn🇰🇷

    We suggest a would-be solution to the solar neutrino tension why solar neutrinos appear to mix differently from reactor antineutrinos, in theoretical respect. To do that, based on an extended theory with light sterile neutrinos added we derive a general transition probability of neutrinos born with one flavor tuning into a different flavor. Three new mass-squared differences are augmented in the extended theory: two $\Delta m_{\mathrm{ABL}}^2\lesssim \mathcal{O}(10^{-11}){\mathrm{eV}}^2$ optimized at astronomical-scale baseline (ABL) oscillation experiments and one $\Delta m_{\mathrm{SBL}}^2\sim \mathcal{O}(1){\mathrm{eV}}^2$ optimized at reactor short-baseline (SBL) oscillation experiments. With a so-called composite matter effect that causes a neutrino flavor change via the effects of sinusoidal oscillation including the Mikheyev-Smirnov-Wolfenstein matter effect, we find that the value of $\Delta m^2$ measured from reactor antineutrino experiments can be fitted with that from the ${}^8$B solar neutrino experiments for roughly $\Delta m_1^2\lesssim 10^{-13}{\mathrm{eV}}^2$ and $\Delta m_2^2\simeq \mathcal{O}(10^{-11}){\mathrm{eV}}^2$. Nonetheless, we find that the current data (solar neutrino alone) is not precise enough to test the proposed scenario. Future precise measurements of ${}^8$B and $pep$ solar neutrinos may confirm and/or improve the value of $\Delta m_2^2$.

    hep-phJHEP(2021)·0 citations
12. 12*

    Parity violation and new physics in superconductors

    Deog Ki Hong🇰🇷

    We propose a new method, using the Andreev reflection at superconductors, to measure parity violation induced by the standard electroweak theory, which in turn constrains the possible parity-violating effects of new physics. The weak neutral currents induce parity-violating, marginal effective operators, though quite tiny, in superconductors. We estimate their effects on superconducting gaps and propose a method to measure the parity-violation from the spin polarization effect, when electrons or holes get Andreev-reflected at the interface between normal metal and a superconductor. Such polarization effects might be comparable to the atomic parity violation and thus naturally give an interesting bound on certain models of new physics, that couples to electrons, such as Majorana mass of active neutrinos or doubly charged Higgs.

    hep-phPLB(2020)·2 citations
13. 13*

    Resummed Gluon Propagator and Debye Screening Effect in a Holonomous Plasma

    Yun Guo🇨🇳 · Zhenpeng Kuang🇨🇳

    Based on the Dyson-Schwinger equation, we compute the resummed gluon propagator in a holonomous plasma that is described by introducing a constant background field for the vector potential $A_0$. Due to the transversality of the holonomous Hard-Thermal-Loop in gluon self-energy, the resummed propagator has a similar Lorentz structure as that in the perturbative Quark-Gluon Plasma where the holonomy vanishes. As for the color structures, since diagonal gluons are mixed in the over-complete double line basis, only the propagators for off-diagonal gluons can be obtained unambiguously. On the other hand, multiplied by a projection operator, the propagators for diagonal gluons, which exhibit a highly non-trivial dependence on the background field, are uniquely determined after summing over the color indices. As an application of these results, we consider the Debye screening effect on the in-medium binding of quarkonium states by analyzing the static limit of the resummed gluon propagator. In general, introducing non-zero holonomy merely amounts to modifications on the perturbative screening mass $m_D$ and the resulting heavy-quark potential, which remains the standard Debye screened form, is always deeper than the screened potential in the perturbative Quark-Gluon Plasma. Therefore, a weaker screening, thus a more tightly bounded quarkonium state can be expected in a holonomous plasma. In addition, both the diagonal and off-diagonal gluons become distinguishable by their modified screening masses ${\mathcal{M}}_D$ and the temperature dependence of the ratio ${\mathcal{M}}_D/T$ shows a very similar behavior as that found in lattice simulations.

    hep-phhep-thnucl-thPRD(2021)·8 citations
14. 14*

    Brownian motion of neutrinos in the Sun [On the distribution of collisions of a neutrino with nucleons of the Sun]

    L.M. Slad🇷🇺

    When solving the solar neutrino problem on the basis of the hypothesis of the existence of a new interaction between electron neutrinos and nucleons, carried by a massless pseudoscalar boson, it becomes necessary to find the consequences of the short-term Brownian motion of neutrinos in the Sun. Earlier, we transmitted these consequences by the effective number of collisions of a neutrino with nucleons of the Sun, assuming the equality of fluxes near the Earth of left- and right-handed solar neutrinos. In this paper, we analyze the transfer of the mentioned consequences by a test geometric distribution of collisions with one free parameter. This distribution provides good agreement between theoretical and experimental results for all five observed processes with solar neutrinos, while it gives the ratio of fluxes near the Earth of left- and right-handed neutrinos equal to 0.516:0.484. With such a ratio, the acceptability of the method of the effective number of collisions of a neutrino with nucleons is again confirmed.

    hep-phastro-ph.SRhep-exnucl-thNucl. Phys. A 1021 (2022) 122425·0 citations
15. 15*

    A fast centrality-meter for heavy-ion collisions at the CBM experiment

    Manjunath Omana Kuttan🇩🇪 · Jan Steinheimer🇩🇪 · Kai Zhou🇩🇪 · Andreas Redelbach🇩🇪 · Horst Stoecker🇩🇪

    A new method of event characterization based on Deep Learning is presented. The PointNet models can be used for fast, online event-by-event impact parameter determination at the CBM experiment. For this study, UrQMD and the CBM detector simulation are used to generate Au+Au collision events at 10 AGeV which are then used to train and evaluate PointNet based architectures. The models can be trained on features like the hit position of particles in the CBM detector planes, tracks reconstructed from the hits or combinations thereof. The Deep Learning models reconstruct impact parameters from 2-14 fm with a mean error varying from -0.33 to 0.22 fm. For impact parameters in the range of 5-14 fm, a model which uses the combination of hit and track information of particles has a relative precision of 4-9 % and a mean error of -0.33 to 0.13 fm. In the same range of impact parameters, a model with only track information has a relative precision of 4-10 % and a mean error of -0.18 to 0.22 fm. This new method of event-classification is shown to be more accurate and less model dependent than conventional methods and can utilize the performance boost of modern GPU processor units.

    hep-phnucl-exnucl-thPLB(2020)·46 citations
16. 16*

    Parity Violation and Chiral Oscillation of Cosmological Relic Neutrinos

    Shao-Feng Ge🇨🇳 · Pedro Pasquini🇨🇳

    The conventional derivation of neutrino oscillation treats neutrino mass eigenstate as plane wave with an overall evolution phase. Nevertheless, due to the intrinsic parity-violating nature of weak interactions, only the left-chiral neutrino can be produced as initial condition. On the other hand, the neutrino mass term connects the left-chiral component to the right-chiral one and unavoidably leads to generation of the later through oscillation. This chiral oscillation has significant consequences on the detection of the cosmological relic neutrinos. The event rate is reduced by a factor of 2 than the conventional prediction.

    hep-phhep-exPLB(2020)·25 citations
17. 17*

    Building Models of Inflation in No-Scale Supergravity

    John Ellis🇬🇧 · Marcos A. G. Garcia🇪🇸 · Natsumi Nagata🇯🇵 · Dimitri V. Nanopoulos🇺🇸 · Keith A. Olive🇺🇸 · Sarunas Verner🇺🇸

    After reviewing the motivations for cosmological inflation formulated in the formalism of supersymmetry, we argue that the appropriate framework is that of no-scale supergravity. We then show how to construct within this framework inflationary models whose predictions for the tilt in the spectrum of scalar perturbations, $n_s$, and the ratio, $r$, of tensor and scalar perturbations coincide with those of the $R+R^2$ model of inflation proposed by Starobinsky. A more detailed study of no-scale supergravity reveals a structure that is closely related to that of $R^2$ modifications of the minimal Einstein-Hilbert action for general relativity, opening avenues for constructing no-scale de Sitter and anti-de Sitter models by combining pairs of Minkowski models, as well as generalizations of the original no-scale Starobinsky models of inflation. We then discuss the phenomenology of no-scale models of inflation, including inflaton decay and reheating, and then the construction of explicit scenarios based on SU(5), SO(10) and string-motivated flipped SU(5)$\times$U(1) GUT models. The latter provides a possible model of almost everything below the Planck scale, including neutrino masses and oscillations, the cosmological baryon asymmetry and cold dark matter, as well as $n_s$ and $r$.

    hep-phastro-ph.COgr-qchep-thInt.J.Mod.Phys.D(2020)·70 citations
18. 18*

    Nonminimal Lorentz-Violating Extensions of Gauge Field Theories

    Zonghao Li🇺🇸

    A general method is presented to build all gauge-invariant terms in gauge field theories, including quantum electrodynamics and quantum chromodynamics. It is applied to two experiments, light-by-light scattering and deep inelastic scattering, to extract first bounds on certain nonminimal coefficients for Lorentz violation.

    hep-ph0 citations
19. 19*

    Unified Framework for $B$-Anomalies, Muon $g-2$, and Neutrino Masses

    K.S. Babu🇺🇸 · P.S. Bhupal Dev🇺🇸 · Sudip Jana🇩🇪 · Anil Thapa🇺🇸

    We present a model of radiative neutrino masses which also resolves anomalies reported in $B$-meson decays, $R_{D^{(\star )}}$ and $R_{K^{(\star )}}$, as well as in muon $g-2$ measurement, $\Delta a_{\mu }$. Neutrino masses arise in the model through loop diagrams involving TeV-scale leptoquark (LQ) scalars $R_2$ and $S_3$. Fits to neutrino oscillation parameters are obtained satisfying all flavor constraints which also explain the anomalies in $R_{D^{(\star )}}$, $R_{K^{(\star )}}$ and $\Delta a_{\mu }$ within $1\sigma$. An isospin-3/2 Higgs quadruplet plays a crucial role in generating neutrino masses; we point out that the doubly-charged scalar contained therein can be produced in the decays of the $S_3$ LQ, which enhances its reach to 1.1 (6.2) TeV at $\sqrt{s}=14$ TeV high-luminosity LHC ($\sqrt{s}=100$ TeV FCC-hh). We also present flavor-dependent upper limits on the Yukawa couplings of the LQs to the first two family fermions, arising from non-resonant dilepton ($pp\to {\ell }^{+}{\ell }^{-}$) processes mediated by $t$-channel LQ exchange, which for 1 TeV LQ mass, are found to be in the range $(0.15-0.36)$. These limits preclude any explanation of $R_{D^{(\star )}}$ through LQ-mediated $B$-meson decays involving ${\nu }_e$ or ${\nu }_{\mu }$ in the final state. We also find that the same Yukawa couplings responsible for the chirally-enhanced contribution to $\Delta a_{\mu }$ give rise to new contributions to the SM Higgs decays to muon and tau pairs, with the modifications to the corresponding branching ratios being at (2-6)% level, which could be tested at future hadron colliders, such as HL-LHC and FCC-hh.

    hep-phhep-exJHEP(2021)·112 citations
20. 20*

    Role of the conserved charges in the chiral symmetry restoration phase transition

    Pedro Costa🇵🇹 · Renan Câmara Pereira🇵🇹 · Constança Providência🇵🇹

    The effect of conserved baryon, isospin and strangeness charges on the behavior of phase transitions in dense matter is studied. Baryonic matter is described within the three-flavor Polyakov$-$Nambu$-$Jona-Lasinio model and several charge fractions $Y_Q$ are considered. The role of the vector interaction, which can be important to describe dense systems, is discussed. Special attention is given to the case with charge fraction $Y_Q=0.4$, due to its importance in heavy-ion collisions and core-collapse supernova matter. It is shown that the possible formation of chiral-symmetric quark matter in the laboratory will be favored in asymmetric matter. Besides, the inclusion of the vector interaction reinforces the formation of quark matter at lower densities.

    hep-phnucl-thPRD(2020)·12 citations
21. 21*

    A modular $A_4$ symmetric Scotogenic model for Neutrino mass and Dark Matter

    Mitesh Kumar Behera🇮🇳 · Shivaramakrishna Singirala🇮🇳 · Subhasmita Mishra🇮🇳 · Rukmani Mohanta🇮🇳

    Modular symmetries have been impeccable in neutrino and quark sectors. This motivated us, therefore, to propose a variant of scotogenic model based on modular $A_4$ symmetry to realize the neutrino mass generation at one-loop level through radiative mechanism. Alongside, the lepton flavour violating process $\mu \to e\gamma$ and the muon $g-2$ anomaly are also addressed. The lightest Majorana fermions turn out to be potential dark matter candidates, made stable by suitable assignment of modular weights. The relic density of the same has been computed with annihilations mediated by inert scalars and new $U(1)$ gauge boson.

    hep-phJ.Phys.G(2022)·67 citations
22. 22*

    A SModelS interface for pyhf likelihoods

    Gaël Alguero🇫🇷 · Sabine Kraml🇫🇷 · Wolfgang Waltenberger🇦🇹

    SModelS is an automatized tool enabling the fast interpretation of simplified model results from the LHC within any model of new physics respecting a ${\mathbb{Z}}_2$ symmetry. We here present a new version of SModelS that can use the full likelihoods now provided by ATLAS in the form of pyhf JSON files. This much improves the statistical evaluation and therefore also the limit setting on new physics scenarios.

    hep-phhep-exComput.Phys.Commun.(2021)·42 citations
23. 23*

    Operator Counting and Soft Blocks in Chiral Perturbation Theory

    Lin Dai🇺🇸 · Ian Low🇺🇸 · Thomas Mehen🇺🇸 · Abhishek Mohapatra🇺🇸

    Chiral perturbation theory (ChPT) is a low-energy effective field theory of QCD and also a nonlinear sigma model based on the symmetry breaking pattern $\mathrm{SU}(N_f)\times \mathrm{SU}(N_f)\to \mathrm{SU}(N_f)$. In the limit of massless $N_f$ quarks, we enumerate the independent operators without external sources in ChPT using an on-shell method, by counting and presenting the soft blocks at each order in the derivative expansion, up to $\mathcal{O}(p^{10})$. Given the massless on-shell condition and total momentum conservation, soft blocks are homogeneous polynomials of kinematic invariants exhibiting the Adler's zero when any external momentum becomes soft and vanishing. In addition, soft blocks are seeds for recursively generating all tree amplitudes of Nambu-Goldstone bosons without recourse to ChPT, and in one-to-one correspondence with the "low energy constants" which are the Wilson coefficients. Relations among operators, such as those arising from equations of motion, integration-by-parts, hermiticity, and symmetry structure, manifest themselves in the soft blocks in simple ways. We find agreements with the existing results up to NNNLO, and make a prediction at N${}^4$LO.

    hep-phhep-thnucl-thPRD(2020)·22 citations
24. 24*

    Regularization of the Nambu-Jona Lasinio model under a uniform magnetic field and the role of the anomalous magnetic moments

    R. M. Aguirre🇦🇷

    The vacuum contribution to quark matter under a uniform magnetic field within the SU(3) version of the Nambu and Jona-Lasinio model is studied. The standard regularization procedure is examined and a new prescription is proposed. For this purpose analytic regularization and a subtraction scheme are used to deal with divergencies depending on the magnetic intensity. This scheme is combined with the standard three momentum cutoff recipe, and reduces to it for vanishing magnetic intensity. Furthermore, the effects of a direct coupling between the anomalous magnetic moments of the quarks and the magnetic field is considered. Single particle properties as well as bulk thermodynamical quantities are studied for a configuration of matter found in neutron stars. A wide range of baryonic densities and magnetic intensities are examined at zero temperature.

    hep-phastro-ph.HEnucl-thPRD(2020)·21 citations
25. 25*

    Interplay between neutrino and gravity portals for FIMP dark matter

    Marco Chianese🇳🇱 · Bowen Fu🇬🇧 · Stephen F. King🇬🇧

    In the classic type I seesaw mechanism with very heavy right-handed (RH) neutrinos, it is possible to account for dark matter via RH neutrino portal couplings to a feebly interacting massive particle (FIMP) dark sector. However, for large RH neutrino masses, gravity can play an important role. We study the interplay between the neutrino portal through the right-handed neutrinos and the gravity portal through the massless spin-2 graviton in producing dark matter particles in the early universe. As a concrete example, we consider the minimal and realistic Littlest Seesaw model with two RH neutrinos, augmented with a dark scalar and a dark fermion charged under a global $U(1{)}_D$ dark symmetry. In the model, the usual seesaw neutrino Yukawa couplings and the right-handed neutrino masses (the lightest being about $5\times 10^{10}$ GeV) are fixed by neutrino oscillations data and leptogenesis. Hence, we explore the parameter space of the two RH neutrino portal couplings, the two dark particle masses and the reheating temperature of the universe, where the correct dark matter relic abundance is achieved through the freeze-in mechanism. In particular, we highlight which class of processes dominate the dark matter production. We find that, despite the presence of the gravity portal, the dark matter production relies on the usual seesaw neutrino Yukawa coupling in some regions of the parameter space, so realising a direct link between dark matter and neutrino phenomenology. Finally, we report the threshold values for the neutrino portal couplings below which the neutrino portal is irrelevant and the Planckian Interacting Dark Matter paradigm is preserved.

    hep-phJCAP(2021)·57 citations
26. 26*

    Neutrino Masses and Hubble Tension via a Majoron in MFV

    Fernando Arias-Aragon🇪🇸 · Enrique Fernandez-Martinez🇪🇸 · Manuel Gonzalez-Lopez🇪🇸 · Luca Merlo🇪🇸

    The recent tension between local and early measurements of the Hubble constant can be explained in a particle physics context. A mechanism is presented where this tension is alleviated due to the presence of a Majoron, arising from the spontaneous breaking of Lepton Number. The lightness of the active neutrinos is consistently explained. Moreover, this mechanism is shown to be embeddable in the Minimal (Lepton) Flavour Violating context, providing a correct description of fermion masses and mixings, and protecting the flavour sector from large deviations from the Standard Model predictions. A QCD axion is also present to solve the Strong CP problem. The Lepton Number and the Peccei-Quinn symmetries naturally arise in the Minimal (Lepton) Flavour Violating setup and their spontaneous breaking is due to the presence of two extra scalar singlets. The Majoron phenomenology is also studied in detail. Decays of the heavy neutrinos and the invisible Higgs decay provide the strongest constraints in the model parameter space.

    hep-phEPJC(2021)·50 citations
27. 27*

    DCTRGAN: Improving the Precision of Generative Models with Reweighting

    Sascha Diefenbacher🇩🇪 · Engin Eren🇩🇪 · Gregor Kasieczka🇩🇪 · Anatolii Korol🇺🇦 · Benjamin Nachman🇺🇸 · David Shih🇺🇸

    Significant advances in deep learning have led to more widely used and precise neural network-based generative models such as Generative Adversarial Networks (GANs). We introduce a post-hoc correction to deep generative models to further improve their fidelity, based on the Deep neural networks using the Classification for Tuning and Reweighting (DCTR) protocol. The correction takes the form of a reweighting function that can be applied to generated examples when making predictions from the simulation. We illustrate this approach using GANs trained on standard multimodal probability densities as well as calorimeter simulations from high energy physics. We show that the weighted GAN examples significantly improve the accuracy of the generated samples without a large loss in statistical power. This approach could be applied to any generative model and is a promising refinement method for high energy physics applications and beyond.

    hep-phhep-exphysics.data-anphysics.ins-det+1JINST(2020)·70 citations
28. 28*

    Status of CME Search Before Isobar Collisions and Methods of Blind Analysis From STAR

    Prithwish Tribedy (for the STAR Collaboration)🇺🇸

    The STAR collaboration is currently pursuing the blind analysis of the data for isobar collisions that was performed at RHIC in the year 2018 to make a decisive test of the Chiral Magnetic Effect (CME). Why is it so difficult to detect signals of CME in the experiment? Do we really understand different sources of background? Why observing similar charge separation between p/d+A and A+A does not stop us from pursuing the search for CME? In this contribution, I attempt to address some of these questions and briefly outline a few recent STAR analyses based on new methods and observables to isolate the possible CME-driven signal and non-CME background contributions at the top RHIC energy. Finally, I describe the procedure for the blind analysis of the isobar data. An outstanding question remains -- what happens if we go down in energy? I address this by discussing how the new event-plane detector (EPD) upgrade provides a new capability at STAR towards CME search using the data from the RHIC BES-II program.

    ↳ nucl-exhep-phnucl-thJ.Phys.Conf.Ser.(2020)·4 citations
29. 29*

    Using High-Energy Neutrinos As Cosmic Magnetometers

    Mauricio Bustamante (Bohr Inst. and DARK Cosmology Ctr.)🇩🇰 · Irene Tamborra (Bohr Inst. and DARK Cosmology Ctr.)🇩🇰

    Magnetic fields are crucial in shaping the non-thermal emission of the TeV-PeV neutrinos of astrophysical origin seen by the IceCube neutrino telescope. The sources of these neutrinos are unknown, but if they harbor a strong magnetic field, then the synchrotron energy losses of the neutrino parent particles---protons, pions, and muons---leave characteristic imprints on the neutrino energy distribution and its flavor composition. We use high-energy neutrinos as "cosmic magnetometers" to constrain the identity of their sources by placing limits on the strength of the magnetic field in them. We look for evidence of synchrotron losses in public IceCube data: 6 years of High Energy Starting Events (HESE) and 2 years of Medium Energy Starting Events (MESE). In the absence of evidence, we place an upper limit of 10 kG-10 MG (95% C.L.) on the average magnetic field strength of the sources.

    ↳ astro-ph.HEhep-phPRD(2020)·31 citations
30. 30*

    Searching for Light in the Darkness: Bounds on ALP Dark Matter with the optical MUSE-Faint survey

    Marco Regis🇮🇹 · Marco Taoso🇮🇹 · Daniel Vaz🇵🇹 · Jarle Brinchmann🇵🇹 · Sebastiaan L. Zoutendijk🇳🇱 · Nicolas F. Bouché🇫🇷 · Matthias Steinmetz🇩🇪

    We use MUSE spectroscopic observations of the dwarf spheroidal galaxy Leo T between 470 and 935 nm to search for radiative decays of axion like particles (ALPs). Under the assumption that ALPs constitute the dark matter component of the Leo T halo, we derive bounds on the effective ALP-two-photon coupling. We improve existing limits by more than one order of magnitude in the ALP mass range 2.7-5.3 eV.

    ↳ astro-ph.COastro-ph.GAhep-phPLB(2021)·89 citations
31. 31*

    Non-universality of hydrodynamics

    Akash Jain🇨🇦 · Pavel Kovtun🇨🇦

    We investigate the effects of stochastic interactions on hydrodynamic correlation functions using the Schwinger-Keldysh effective field theory. We identify new "stochastic transport coefficients" that are invisible in the classical constitutive relations, but nonetheless affect the late-time behaviour of hydrodynamic correlation functions through loop corrections. These results indicate that classical transport coefficients do not provide a universal characterisation of long-distance, late-time correlations even within the framework of fluctuating hydrodynamics.

    ↳ hep-thcond-mat.stat-mechhep-phmath-ph+2PRL(2022)·48 citations
32. 32*

    Exact one-loop false vacuum decay rate

    Victor Guada🇸🇮 · Miha Nemevšek🇸🇮

    We discuss an exact false vacuum decay rate at one loop for a real and complex scalar field in a quartic-quartic potential with two tree-level minima. The bounce solution is used to compute the functional determinant from both fluctuations. We obtain the finite product of eigenvalues and remove translational zero modes. The orbital modes are regularized with the zeta function and we end up with a complete renormalized decay rate. We derive simple expansions in the thin and thick wall limits and determine their validity.

    ↳ hep-thgr-qchep-phPRD(2020)·19 citations
33. 33*

    An Update to the Letter of Intent for MATHUSLA: Search for Long-Lived Particles at the HL-LHC

    Cristiano Alpigiani🇺🇸 · Juan Carlos Arteaga-Velázquez🇲🇽 · Austin Ball🇨🇭 · Liron Barak🇮🇱 · Jared Barron🇨🇦 · Brian Batell🇺🇸 · James Beacham🇺🇸 · Yan Benhammo🇮🇱 · Karen Salomé Caballero-Mora🇲🇽 · Paolo Camarri🇮🇹 · Roberto Cardarelli🇮🇹 · John Paul Chou🇺🇸 and 71 other authors

    We report on recent progress in the design of the proposed MATHUSLA Long Lived Particle (LLP) detector for the HL-LHC, updating the information in the original Letter of Intent (LoI), see CDS:LHCC-I-031, arXiv:1811.00927. A suitable site has been identified at LHC Point 5 that is closer to the CMS Interaction Point (IP) than assumed in the LoI. The decay volume has been increased from 20 m to 25 m in height. Engineering studies have been made in order to locate much of the decay volume below ground, bringing the detector even closer to the IP. With these changes, a 100 m x 100 m detector has the same physics reach for large c$\tau$ as the 200 m x 200 m detector described in the LoI and other studies. The performance for small c$\tau$ is improved because of the proximity to the IP. Detector technology has also evolved while retaining the strip-like sensor geometry in Resistive Plate Chambers (RPC) described in the LoI. The present design uses extruded scintillator bars read out using wavelength shifting fibers and silicon photomultipliers (SiPM). Operations will be simpler and more robust with much lower operating voltages and without the use of greenhouse gases. Manufacturing is straightforward and should result in cost savings. Understanding of backgrounds has also significantly advanced, thanks to new simulation studies and measurements taken at the MATHUSLA test stand operating above ATLAS in 2018. We discuss next steps for the MATHUSLA collaboration, and identify areas where new members can make particularly important contributions.

    ↳ physics.ins-dethep-exhep-ph125 citations
34. 34*

    The GW190521 Mass Gap Event and the Primordial Black Hole Scenario

    V. De Luca🇨🇭 · V. Desjacques🇮🇱 · G. Franciolini🇨🇭 · P. Pani🇮🇹 · A. Riotto🇨🇭

    The LIGO/Virgo Collaboration has recently observed GW190521, the first binary black hole merger with at least the primary component mass in the mass gap predicted by the pair-instability supernova theory. This observation disfavors the standard stellar-origin formation scenario for the heavier black hole, motivating alternative hypotheses. We show that GW190521 cannot be explained within the Primordial Black Hole (PBH) scenario if PBHs do not accrete during their cosmological evolution, since this would require an abundance which is already in tension with current constraints. On the other hand, GW190521 may have a primordial origin if PBHs accrete efficiently before the reionization epoch.

    ↳ astro-ph.COgr-qchep-phPRL(2021)·172 citations
35. 35*

    Jet quenching in the hadron gas: An exploratory study

    Hannah Elfner🇩🇪 · Philipp Dorau🇩🇪 · Jean-Bernard Rose🇩🇪 · Daniel Pablos🇳🇴

    In most calculations of hard particle suppression in heavy-ion reactions the hadronic stage has been neglected due to formation time arguments. Most of the hard particle shower exits the hot and dense medium before the system enters the hadronic evolution. In this contribution, a first assessment within the hadronic transport approach SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) of rescattering effects on hard particles is presented. In particular, it is shown that the hadronic energy loss depends on the particle species as well as the energy of the probe. A parametrization for the $⟨\tilde{q}⟩$ parameter as a function of temperature and particle energy is given for pions. Overall, major effects of the hadronic stage are expected in the transverse momentum range from 2-10 GeV and therefore jet sub-structure analysis and (hard-soft) correlation observables might be affected.

    ↳ nucl-thhep-phnucl-exPoS(2021)·2 citations
36. 36*

    Extremely Dense Gamma-Ray Pulses in Electron Beam-Multifoil Collisions

    Archana Sampath🇩🇪 · Xavier Davoine🇫🇷 · Sébastien Corde🇫🇷 · Laurent Gremillet🇫🇷 · Max Gilljohann🇫🇷 · Maitreyi Sangal🇩🇪 · Christoph H. Keitel🇩🇪 · Robert Ariniello🇺🇸 · John Cary🇺🇸 · Henrik Ekerfelt🇺🇸 · Claudio Emma🇺🇸 · Frederico Fiuza🇺🇸 and 17 other authors

    Sources of high-energy photons have important applications in almost all areas of research. However, the photon flux and intensity of existing sources is strongly limited for photon energies above a few hundred keV. Here we show that a high-current ultrarelativistic electron beam interacting with multiple submicrometer-thick conducting foils can undergo strong self-focusing accompanied by efficient emission of gamma-ray synchrotron photons. Physically, self-focusing and high-energy photon emission originate from the beam interaction with the near-field transition radiation accompanying the beam-foil collision. This near field radiation is of amplitude comparable with the beam self-field, and can be strong enough that a single emitted photon can carry away a significant fraction of the emitting electron energy. After beam collision with multiple foils, femtosecond collimated electron and photon beams with number density exceeding that of a solid are obtained. The relative simplicity, unique properties, and high efficiency of this gamma-ray source open up new opportunities for both applied and fundamental research including laserless investigations of strong-field QED processes with a single electron beam.

    ↳ physics.plasm-phhep-phphysics.acc-phPRL(2021)·36 citations
37. 37*

    Low Mass Black Holes from Dark Core Collapse

    Basudeb Dasgupta🇮🇳 · Ranjan Laha🇨🇭 · Anupam Ray🇮🇳

    Unusual masses of black holes being discovered by gravitational wave experiments pose fundamental questions about the origin of these black holes. Black holes with masses smaller than the Chandrasekhar limit $\approx 1.4M_{\odot }$ are essentially impossible to produce through stellar evolution. We propose a new channel for production of low mass black holes: stellar objects catastrophically accrete non-annihilating dark matter, and the small dark core subsequently collapses, eating up the host star and transmuting it into a black hole. The wide range of allowed dark matter masses allows a smaller effective Chandrasekhar limit, and thus smaller mass black holes. We point out several avenues to test our proposal, focusing on the redshift dependence of the merger rate. We show that redshift dependence of the merger rate can be used as a probe of the transmuted origin of low mass black holes.

    ↳ astro-ph.HEastro-ph.COgr-qchep-phPRL(2021)·119 citations
38. 38*

    Multi-Dimensional Solution of Fast Neutrino Conversions in Binary Neutron Star Merger Remnants

    Ian Padilla-Gay🇩🇰 · Shashank Shalgar🇩🇰 · Irene Tamborra (Niels Bohr Institute)🇩🇰

    Fast pairwise conversions of neutrinos are predicted to be ubiquitous in neutron star merger remnants with potentially major implications on the nucleosynthesis of the elements heavier than iron. We present the first sophisticated numerical solution of the neutrino flavor evolution above the remnant disk within a (2+1+1) dimensional setup: two spatial coordinates, one angular variable, and time. We look for a steady-state flavor configuration above the remnant disk. Albeit the linear stability analysis predicts flavor instabilities at any location above the remnant disk, our simulations in the non-linear regime show that fast pairwise conversions lead to minimal neutrino mixing (<1%); flavor equilibration is never achieved in our models. Importantly, fast neutrino conversions are more prominent within localized regions near the edges of the (anti)neutrino decoupling surfaces and almost negligible in the polar region of the remnant. Our findings on the role of fast pairwise conversions should be interpreted with caution because of the approximations intrinsic to our setup and advocate for further work within a more realistic framework.

    ↳ astro-ph.HEhep-phJCAP(2021)·51 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.