HEP Phenomenology·hep-ph

Wed·Jul 17, 2019Wednesday·July 17, 2019

27 papers—19 primary·8 cross-listed·reconstructed*

01*
Forays into the dark side of the swamp
Iason Baldes🇧🇪 · Debtosh Chowdhury🇫🇷 · Michel H.G. Tytgat🇧🇪
Motivated by the swampland conjectures, we study cosmological signatures of a quintessence potential which induces time variation in the low energy effective field theory. After deriving the evolution of the quintessence field, we illustrate its possible ramifications by exploring putative imprints in a number of directions of particle phenomenology. We first show that a dark matter self-interaction rate increasing with time gives a novel way of reconciling the large self interactions required to address small scale structure issues with the constraint coming from clusters. Next, we study the effects of kinetic mixing variation during the radiation dominated era on freeze-in dark matter production. Last, we elucidate quintessence effects on the restoration of the electroweak symmetry at finite temperature and the lifetime of the electroweak vacuum through a modification of the effective Higgs mass and quartic coupling.
hep-phastro-ph.COhep-thPRD(2019)·12 citations
02*
Unitarization effects in EFT predictions of WZ scattering at the LHC
C. Garcia-Garcia🇪🇸 · M. J. Herrero🇪🇸 · R. A. Morales🇪🇸
Effective field theories are an incredibly powerful tool in order to study and understand the true nature of the symmetry breaking sector dynamics of the Standard Model. However, they can suffer from some theoretical problems such as that of unitarity violation. Nevertheless, in order to interpret experimental data correctly a fully unitary prescription is needed. To this purpose, unitarization methods are addressed, but each of them leads to a different (unitary) prediction. Because of this, there is an inherent theoretical uncertainty in the determination of the effective field theory parameters due to the choice of one unitarization scheme. In this work, we quantify this uncertainty assuming a strongly interacting electroweak symmetry breaking sector, described by the effective electroweak chiral Lagrangian. We focus on the bosonic part of this effective Lagrangian and choose in particular the WZ scattering as our main VBS channel to study the sensitivity to new physics at the LHC. We study the different predictions of various well known unitarization methods, considering the full coupled system of helicity amplitudes, and construct the 95\% confidence level exclusion regions for the most relevant electroweak chiral Lagrangian parameters, given by the two anomalous quartic gauge couplings $a_{4}$ and $a_{5}$ . This provides a consistent analysis of the different constraints on EChL parameters that can be achieved by using different unitarization methods in a combined way.
hep-phPRD(2019)·40 citations
03*
Lepton flavor violation from SUSY with non-universal scalars
Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Hasan Serce🇺🇸
Right-handed neutrinos in supersymmetric models can act as the source of lepton flavor violation (LFV). We present experimental implications of lepton flavor-violating processes within a supersymmetric type-I seesaw framework in the three-extra-parameter non-universal Higgs model (NUHM3) for large (PMNS-like) and small (CKM-like) Yukawa mixing scenarios. We highlight LFV predictions for the natural (low $Δ_{EW}$ ) portion of parameter space. Our numerical analysis includes full 2-loop renormalization group running effects for the three neutrino masses and mass matrices. We show the projected discovery reach of various LFV experiments ( $i.e.$ Mu2e, Mu3e, MEG-II, Belle-II), and specify regions that have already been excluded by the LHC searches. Our results depend strongly on whether one has a normal sneutrino hierarchy (NSH) or an inverted sneutrino hierarchy (ISH). Natural SUSY with a NSH is already excluded by MEG-2013 results while large portions of ISH have been or will soon be tested. However, LFV processes from natural SUSY with small Yukawa mixing and an ISH seem below any projected sensitivities. A substantial amount of the remaining parameter space of models with large PMNS-like sneutrino mixing will be probed by Mu2e and MEG-II experiments whereas small, CKM-like Yukawa mixing predicts LFV decays which can hide from LFV experiments.
hep-phPhys.Rev.Research.(2019)·3 citations
04*
Neutral Higgs decays $H \to Z γ, γ γ$ in 3-3-1 models
H. T. Hung🇻🇳 · T. T. Hong🇻🇳 · H. H. Phuong🇻🇳 · H. L. T. Mai🇻🇳 · L. T.Hue🇻🇳
The significance of new physics appearing in the loop-induced decays of neutral Higgs bosons into pairs of dibosons $γ γ$ and $Z γ$ will be discussed in the framework of the 3-3-1 models based on a recent work~\cite{Okada:2016whh}, where the Higgs sector becomes effectively the same as that in the two Higgs doublet models (2HDM) after the first symmetry breaking from $S U (3)_{L}$ scale into the electroweak scale. For large $S U (3)_{L}$ scale $v_{3} ≃ 10$ TeV, dominant one-loop contributions to the two decay amplitudes arise from only the single charged Higgs boson predicted by the 2HDM, leading to that experimental constraint on the signal strength $μ_{γ γ}^{331}$ of the Standard Model-like Higgs boson decay $h \to γ γ$ will result in a strict upper bound on the signal strength $μ_{Z γ}^{331}$ of the decay $h \to Z γ$ . For a particular model with lower $v_{3}$ around 3 TeV, contributions from heavy charged gauge and Higgs bosons may have the same order, therefore may give strong destructive or constructive correlations. As a by-product, a deviation from the SM prediction $∣ μ_{γ γ}^{331} - 1∣ \leq 0.04$ still allows $∣ μ_{Z γ}^{331} - 1∣$ to reach values near 0.1. We also show that there exists an $C P$ -even neutral Higgs boson $h_{3}^{0}$ predicted by the 3-3-1 models, but beyond the 2HDM, has an interesting property that the branching ratio Br $(h_{3}^{0} \to γ γ)$ is very sensitive to the parameter $β$ used to distinguish different 3-3-1 models.
hep-phPRD(2019)·30 citations
05*
Radiative Corrections to Neutron and Nuclear Beta Decays Revisited
Andrzej Czarnecki🇨🇦 · William J. Marciano🇺🇸 · Alberto Sirlin🇺🇸
The universal radiative corrections common to neutron and super-allowed nuclear beta decays (also known as ``inner'' corrections) are revisited in light of a recent dispersion relation study that found $+ 2.467 (22) %$ , i.e.~about $2.4 σ$ larger than the previous evaluation. For comparison, we consider several alternative computational methods. All employ an updated perturbative QCD four-loop Bjorken sum rule (BjSR) defined QCD coupling supplemented with a nucleon form factor based Born amplitude to estimate axial-vector induced hadronic contributions. In addition, we now include hadronic contributions from low $Q^{2}$ loop effects based on duality considerations and vector meson resonance interpolators. Our primary result, $2.426 (32) %$ corresponds to an average of a Light Front Holomorphic QCD approach and a three resonance interpolator fit. It reduces the dispersion relation discrepancy to approximately $1.1 σ$ and thereby provides a consistency check. Consequences of our new radiative correction estimate, along with that of the dispersion relation result, for CKM unitarity are discussed. The neutron lifetime- $g_{A}$ connection is updated and shown to suggest a shorter neutron lifetime $< 879$ s. We also find an improved bound on exotic, non-Standard Model, neutron decays or oscillations of the type conjectured as solutions to the neutron lifetime problem, $BR (n \to exotics) < 0.16%$ .
hep-phnucl-exnucl-thPRD(2019)·208 citations
06*
Searching for light WIMPS in view of neutron decay to dark matter
J.D. Vergados (Physics Department University of Ioannina, Ioannina, Greece)🇬🇷
In the present work we examine the implications on dark matter searches of the possibility of a partial decay of a neutron into a dark matter particle, slightly lighter than itself. Such a scenario recently proposed is required to bridge the discrepancy between the results of two different experiments measuring the life time of the neutron. It was subsequently suggested that this light dark matter candidate could make up the whole of dark matter in the universe. We thus first compute the nucleon cross section based on such models. Then we proceed explore the various signatures appearing in dark matter searches involving nuclear targets, in the case of such a light dark matter candidate.
hep-phJ.Phys.G(2019)·1 citation
07*
Testing production scenarios for (anti-)(hyper-)nuclei with multiplicity-dependent measurements at the LHC
Francesca Bellini🇨🇭 · Alexander P. Kalweit🇨🇭
The production of light anti- and hyper-nuclei provides unique observables to characterise the system created in high energy proton-proton (pp), proton-nucleus (pA) and nucleus-nucleus (AA) collisions. In particular, nuclei and hyper-nuclei are special objects with respect to non-composite hadrons (such as pions, kaons, protons, etc.), because their size is comparable to a fraction or the whole system created in the collision. Their formation is typically described within the framework of coalescence and thermal-statistical production models. In order to distinguish between the two production scenarios, we propose to measure the coalescence parameter B $_{A}$ for different anti- and hyper-nuclei (that differ by mass, size and internal wave-function) as a function of the size of the particle emitting source. The latter can be controlled by performing systematic measurements of light (anti-)(hyper-)nuclei in different collision systems (pp, pA, AA) and as a function of the multiplicity of particles created in the collision. While it is often argued that the coalescence and the thermal model approach give very similar predictions for the production of light nuclei in heavy-ion collisions, our study shows that large differences can be expected for hyper-nuclei with extended wave-functions, as the hyper-triton. We compare the model predictions with data from the ALICE experiment and we discuss perspectives for future measurements with the upgraded detectors during the High-Luminosity LHC phase in the next decade.
hep-phActa Phys.Polon.B(2019)·10 citations
08*
Chaotic Inflation from the MSSM Along Flat $D$ -Term Trajectory
Zurab Tavartkiladze🇬🇪
Within the MSSM we propose the chaotic inflationary scenario in which the inflaton field is a combination of sleptons and the Higgs field states evolving along the $D$ -term flat direction. In the inflation and postinflation reheating processes, a decisive role is played by the MSSM Yukawa superpotential. The vacuum energy during the inflationary era is mainly from the muonic Yukawa coupling, while the inflaton decay and subsequent reheating process dominantly proceeds due to the strange quark Yukawa term. Because of these, the presented scenario is predictive and the results obtained agree well with cosmological observations. In particular, the scalar spectral index and the tensor-to-scalar ratio are respectively, $n_{s} ≃ 0.966$ and $r = 0.00117$ . The reheating temperature is found to be $T_{r} ≃ 7.2 \times 1 0^{7}$ GeV.
hep-phastro-ph.COhep-thPRD(2019)·1 citation
09*
Pseudoscalar-Meson Contributions to g-2 via Schwinger's Sum Rule
Franziska Hagelstein (AEC Bern)🇨🇭 · Vladimir Pascalutsa (JGU Mainz)🇩🇪
The Schwinger sum rule is presented as a new promising tool to study the hadronic contributions to the muon anomalous magnetic moment. In particular, we show preliminary results for the light-by-light scattering contribution of pseudoscalar mesons.
hep-phnucl-thPoS(2019)·5 citations
10*
The light-fermion contribution to the exact Higgs-gluon form factor in QCD
Robert V. Harlander🇩🇪 · Mario Prausa🇩🇪 · Johann Usovitsch🇮🇪
An analytical expression for the three-loop form factors for $g g H$ and $γ γ H$ is derived for the contributions which involve massless quark loops. The result is expressed in terms of harmonic polylogarithms. It fully agrees with previously obtained kinematical expansions, and confirms a recent semi-numerical approximation which extends over the full kinematic range.
hep-phJHEP(2019)·26 citations
11*
Revisiting model relations between T-odd transverse-momentum dependent parton distributions and generalized parton distributions
B. Pasquini🇮🇹 · S. Rodini🇮🇹 · A. Bacchetta (Pavia U. & INFN, Pavia)🇮🇹
We revisit the connection between generalized parton distributions in impact parameter space and T-odd effects in single spin asymmetries of the semi-inclusive deep inelastic process. We show that nontrivial relations can be established only under very specific conditions, typically realized only in models that describe hadrons as two-body bound systems and involving a helicity-conserving coupling between the gauge boson and the spectator system. Examples of these models are the the scalar-diquark spectator model or the quark-target model for the nucleon, and relativistic models for the pion at the lowest order in the Fock-space expansion.
hep-phnucl-thPRD(2019)·23 citations
12*
Sensitivity of future lepton colliders and low-energy experiments to charged lepton flavor violation from bileptons
Tong Li🇨🇳 · Michael A. Schmidt🇦🇺
The observation of charged lepton flavor violation is a clear sign of physics beyond the Standard Model (SM). In this work, we investigate the sensitivity of future lepton colliders to charged lepton flavor violation via on-shell production of bileptons, and compare their sensitivity with current constraints and future sensitivities of low-energy experiments. Bileptons couple to two charged leptons with possibly different flavors and are obtained by expanding the general SM gauge invariant Lagrangians with or without lepton number conservation. We find that future lepton colliders will provide complementary sensitivity to the charged-lepton-flavor-violating couplings of bileptons compared with low-energy experiments. The future improvements of muonium-antimuonium conversion, lepton flavor non-universality in leptonic {\tau} decays, electroweak precision observables and the anomalous magnetic moments of charged leptons will also be able to probe similar parameter space.
hep-phPRD(2019)·15 citations
13*
Fine-tuned Spin-3/2 and the Hierarchy Problem
Ozan Sargın🇹🇷
In the past, Kundu et al. and Chakraborty et al. used extra scalar fields to cancel the quadratic divergences in the Higgs mass squared and they determined the mass of the required scalar field. In this work, a spin-3/2 particle has been used in the same manner to nullify the power-law divergences and it is determined that the mass of the spin-3/2 particle resides in the ball park of the GUT scale.
hep-phAdv.High Energy Phys.(2020)·0 citations
14*
Probing invisible decay of dark photon at BESIII and future STCF via monophoton searches
Yu Zhang🇨🇳 · Wei-Tao Zhang🇨🇳 · Mao Song🇨🇳 · Xue-An Pan🇨🇳 · Zhong-Ming Niu🇨🇳 · Gang Li🇨🇳
We propose to search the monophoton events at the BESIII detector and future Super Tau Charm Factory to probe the sub-GeV dark photon decay into lighter dark matter. We compute the cross section due to the dark photon associated a standard model photon production, and study the corresponding standard model irreducible/reducible backgrounds. By using the data about 17 fb $^{- 1}$ collected at the BESIII detector since 2011, we derive new leading limits of the mixing strength $ε$ , $ε ≲ (1.1 - 1.6) \times 1 0^{- 4}$ , in the mass range of 0.04 GeV $≲ m_{A^{'}} ≲$ 3 GeV. With 30 ab $^{- 1}$ data, STCF running at $s = 2$ GeV, can probe $ε$ down to 5.1 $\times 1 0^{- 6}$ when $m_{A^{'}} = 1$ GeV. For models of scalar and fermionic light thermal dark matter production via dark photon, we present the constrains on the dimensionless dark matter parameter $y = ε^{2} α_{D} (m_{χ} / m_{A^{'}})^{4}$ as function of the DM mass $m_{χ}$ at BESIII and future STCF, conventionally assuming the dark coupling constant $α_{D} = 0.5$ and $m_{A^{'}} = 3 m_{χ}$ . We find that BESIII can exclude model of scalar, Majorana, and pseudo-Dirac (with a small splitting) DM for the mass region 0.03 $\sim$ 1 GeV, 0.04 $\sim$ 1 GeV and 0.4 $\sim$ 1 GeV respectively. For values $α_{D} ≲ 0.005$ , combining the results from 2 GeV STCF with 30 ab $^{- 1}$ data and BaBar, one can exclude the above three DM models in the mass region 0.001 GeV $≲ m_{χ} ≲$ 1 GeV.
hep-phhep-exPRD(2019)·36 citations
15*
Ring Laser Gyroscope Tests of Lorentz Symmetry
Max L. Trostel🇺🇸 · Serena Moseley🇺🇸 · Nicholas Scaramuzza🇺🇸 · Jay D. Tasson🇺🇸
Interferometric gyroscope systems are being developed with the goal of measuring general-relativistic effects including frame-dragging effects. Such devices are also capable of performing searches for Lorentz violation. We summarize efforts that relate gyroscope measurements to coefficients for Lorentz violation in the gravity sector of the Standard-Model Extension.
hep-phgr-qc2 citations
16*
The $sin (2 ϕ - ϕ_{S})$ azimuthal asymmetry in the pion induced Drell-Yan process within TMD factorization
Hui Li🇨🇳 · Xiaoyu Wang🇨🇳 · Zhun Lu🇨🇳
We investigate the single transverse-spin asymmetry with a $sin (2 ϕ - ϕ_{S})$ modulation in the pion-induced Drell-Yan process within the theoretical framework of the transverse momentum dependent factorization. The asymmetry is contributed by the convolution of the Boer-Mulders function and the transversity. We adopt the model results for the distributions of the pion meson from the light-cone wavefunction approach and the available parametrization for the distributions of the proton to numerically estimate the $sin (2 ϕ - ϕ_{S})$ asymmetry in $π^{-} p$ Drell-Yan at the kinematics of the COMPASS at CERN. To implement the TMD evolution formalism of parton distribution functions, we apply the recently extracted nonperturbative Sudakov form factor associated with the distribution functions of the proton and the pion. It is found that our prediction on the single transverse-spin dependent asymmetry $sin (2 ϕ - ϕ_{S})$ as functions of $x_{p}$ , $x_{π}$ , $x_{F}$ and $q_{⊥}$ is qualitatively consistent with the recent COMPASS measurement in both sign and magnitude.
hep-phhep-exPRD(2020)·10 citations
17*
Vacuum Stability and Symmetry Breaking in Left-Right Symmetric Model
Garv Chauhan🇺🇸
We derive analytic necessary and sufficient conditions for the vacuum stability of the left-right symmetric model by using the concepts of copositivity and gauge orbit spaces. We also derive the conditions sufficient for successful symmetry breaking and the existence of a correct vacuum. We then compare results obtained from the derived conditions with those from numerical minimization of the scalar potential. Finally, we discuss the renormalization group analysis of the scalar quartic couplings through an example study that satisfies vacuum stability, perturbativity, unitarity and experimental bounds on the physical scalar masses.
hep-phJHEP(2019)·34 citations
18*
Bino-wino coannihilation as a prediction in the $E_{7}$ unification of families
Tsutomu T. Yanagida🇨🇳 · Wen Yin🇰🇷 · Norimi Yokozaki🇯🇵
We study the phenomenological consequences of the supersymmetric (SUSY) $E_{7} / S U (5) \times U (1)^{3}$ non-linear sigma model coupled to supergravity, where the three generations of quark and lepton chiral multiplets appear as (pseudo) Nambu Goldstone (NG) multiplets, that is, the origin of the three families is explained. To break SUSY, we introduce a SUSY breaking field charged under some symmetry avoiding the Polonyi problem. The gaugino mass spectrum is almost uniquely determined when one requires the electroweak vacuum to be (meta)stable: it would be a miracle that the mass difference between the bino and wino turns out to be within $O (1) %$ at the low energy. Thus, a bino-wino coannihilation is naturally predicted, which can explain the correct relic abundance of dark matter. Moreover, we find that the bottom-tau Yukawa couplings and the gauge couplings are unified up to $O (1) %$ in most of the viable region. This scenario can be fully tested at the LHC and future collider experiments since the gauginos and some of the pseudo-NG bosons are light. An axion-like multiplet, which can be identified with the QCD axion, is also predicted.
hep-phastro-ph.COgr-qchep-exJHEP(2019)·17 citations
19*
Cascade decays of Heavy Higgs bosons through vectorlike quarks
Radovan Dermisek🇺🇸 · Enrico Lunghi🇺🇸 · Seodong Shin🇺🇸
We study cascade decays of heavy neutral Higgs bosons through vectorlike quarks. We focus on scenarios where decay modes into pairs of vectorlike quarks are not kinematically open which extends the sensitivity of the LHC to larger masses. Assuming only mixing with the third family of standard model quarks the new decay modes of heavy Higgs bosons are: $H \to t_{4} t \to W b t, Z tt, h tt$ and $H \to b_{4} b \to W t b, Z bb, hbb$ , where $t_{4}$ ( $b_{4}$ ) is the new up-type (down-type) quark mass eigenstate. In the numerical analysis we assume the CP even Higgs boson in the two Higgs doublet model type-II but the signatures are relevant for many other scenarios. We identify the region of the parameter space where these decay modes are significant or can even dominate, and thus they provide the best opportunities for the simultaneous discovery of a new Higgs boson and vectorlike quarks. We further explore the reach of the High Luminosity LHC for two representative decay modes, $t_{4} \to Z t \to ℓℓ t$ and $b_{4} \to Z b \to ℓℓ b$ , and found that cross sections at a 0.1 fb level can be probed with simple cut based analyses. We also find that the rates for Higgs cascade decays can be much larger than the rates for a single production of vectorlike quarks. Furthermore, the reach for vectorlike quarks in Higgs cascade decays and pair production extends to comparable masses.
hep-phhep-exJHEP(2020)·15 citations
20*
Measuring neutrino masses with large-scale structure: Euclid forecast with controlled theoretical error
Anton Chudaykin🇷🇺 · Mikhail M. Ivanov🇺🇸
We present a Markov-Chain Monte-Carlo (MCMC) forecast for the precision of neutrino mass and cosmological parameter measurements with a Euclid-like galaxy clustering survey. We use a complete perturbation theory model for the galaxy one-loop power spectrum and tree-level bispectrum, which includes bias, redshift space distortions, IR resummation for baryon acoustic oscillations and UV counterterms. The latter encapsulate various effects of short-scale dynamics which cannot be modeled within perturbation theory. Our MCMC procedure consistently computes the non-linear power spectra and bispectra as we scan over different cosmologies. The second ingredient of our approach is the theoretical error covariance which captures uncertainties due to higher-order non-linear corrections omitted in our model. Having specified characteristics of a Euclid-like spectroscopic survey, we generate and fit mock galaxy power spectrum and bispectrum likelihoods. Our results suggest that even under very agnostic assumptions about non-linearities and short-scale physics a future Euclid-like survey will be able to measure the sum of neutrino masses with a standard deviation of 28 meV. When combined with the Planck cosmic microwave background likelihood, this uncertainty decreases to 13 meV. Over-optimistically reducing the theoretical error on the bispectrum down to the two-loop level marginally tightens this bound to 11 meV. Moreover, we show that the future large-scale structure (LSS) spectroscopic data will greatly improve constraints on the other cosmological parameters, e.g. reaching a percent (per mille) error on the Hubble constant with LSS alone (LSS + Planck).
↳ astro-ph.COhep-phJCAP(2019)·158 citations
21*
Death and Serious Injury by Dark Matter
Jagjit Singh Sidhu🇺🇸 · Robert J Scherrer🇺🇸 · Glenn Starkman🇺🇸
Macroscopic dark matter refers to a variety of dark matter candidates that would be expected to (elastically) scatter off of ordinary matter with a large geometric cross-section. A wide range of macro masses $M_{X}$ and cross-sections $σ_{X}$ remain unprobed. We show that over a wide region within the unexplored parameter space, collisions of a macro with a human body would result in serious injury or death. We use the absence of such unexplained impacts with a well-monitored subset of the human population to exclude a region bounded by $σ_{X} \geq 1 0^{- 8} - 1 0^{- 7}$ cm $^{2}$ and $M_{X} < 50$ kg. Our results open a new window on dark matter: the human body as a dark matter detector.
↳ astro-ph.COhep-phPLB(2020)·37 citations
22*
Remote Dipole Field Reconstruction with Dusty Galaxies
Fiona McCarthy🇨🇦 · Matthew C. Johnson🇨🇦
The kinetic Sunyaev Zel'dovich (kSZ) effect, cosmic microwave background (CMB) temperature anisotropies induced by scattering of CMB photons from free electrons, forms the dominant blackbody component of the CMB on small angular scales. Future CMB experiments on the resolution/sensitivity frontier will measure the kSZ effect with high significance. Through the cross-correlation with tracers of structure, it will be possible to reconstruct the remote CMB dipole field (e.g. the CMB dipole observed at different locations in the Universe) using the technique of kSZ tomography. In this paper, we derive a quadratic estimator for the remote dipole field using the Cosmic Infrared Background (CIB) as a tracer of structure. We forecast the ability of current and next-generation measurements of the CMB and CIB to perform kSZ tomography. The total signal-to-noise of the reconstruction is order unity for current datasets, and can improve by a factor of up to $1 0^{3}$ for future datasets, based on statistical error only. The CIB-based reconstruction is highly correlated with a galaxy survey-based reconstruction of the remote dipole field, which can be exploited to improve constraints on cosmological parameters and models for the CIB and distribution of baryons.
↳ astro-ph.COastro-ph.GAgr-qchep-phPRD(2020)·13 citations
23*
On the origin of the gamma-ray emission from Omega Centauri: Milisecond pulsars and dark matter annihilation
Javier Reynoso-Cordova🇲🇽 · Oleg Burgueño🇲🇽 · Alex Geringer-Sameth🇬🇧 · Alma X. Gonzalez-Morales🇲🇽 · Stefano Profumo🇺🇸 · O. Valenzuela🇲🇽
We explore two possible scenarios to explain the observed gamma-ray emission associated with the atypical globular cluster Omega-Centauri: emission from millisecond pulsars (MSP) and dark matter (DM) annihilation. In the first case the total number of MSPs needed to produce the gamma-ray flux is compatible with the known (but not confirmed) MSP candidates observed in X-rays. A DM interpretation is motivated by the possibility of Omega-Centauri being the remnant core of an ancient dwarf galaxy hosting a surviving DM component. At least two annihilation channels, light quarks and muons, can plausibly produce the observed gama-ray spectrum. We outline constraints on the parameter space of DM mass versus the product of the pair-annihilation cross section and integrated squared DM density (the so-called J-factor). We translate upper limits on the dark matter content of Omega-Centauri into lower limits on the annihilation cross section. This shows s-wave annihilation into muons to be inconsistent with CMB observations, while a small window for annihilation into light quarks is allowed. Further analysis of Omega-Centauri's internal kinematics, and/or additional information on the resident MSP population will yield much stronger constraints and shed light about the origin of this otherwise mysterious gamma-ray source.
↳ astro-ph.HEastro-ph.COhep-phJCAP(2021)·15 citations
24*
Collision of ultra-relativistic proton with strong magnetic field: production of ultra-high energy photons and neutrinos
Ye-Fei Yuan🇨🇳 · Xin-Yue Shi (USTC)🇨🇳
Proton-proton interaction and photo-hadronic interaction in cosmic accelerators are the two main channels for the production of cosmic ultra-high energy photons and neutrinos (TeV-PeV). In this Letter, we use FWW approach to obtain the production of cosmic ultra-high energy photons and neutrinos from the collision between UHE proton with magnetic field which could be considered as the virtualphoton in the rest frame of UHE proton. We name this as $pB$ process. The threshold for the occurrence of the $pB$ process is that the combination of the Lorentz factor of proton and the strength of the magnetic field is about $γ_{p} B ≃ 5 \times 1 0^{18}$ Gauss. Beyond this threshold, the rate of energy loss of proton due to the $pB$ process is about three orders higher than that due to the synchrotron radiation of proton in the same magnetic field. The $pB$ process might potentially happen in the atmosphere of white dwarfs, neutron stars or even that of stellar massive black holes.
↳ astro-ph.HEhep-phnucl-thPLB(2019)·2 citations
25*
Generic energy transport solutions to the solar abundance problem -- a hint of new physics
Anton V. Sokolov🇩🇪
First, we briefly review the solar abundance problem and its current status. We start with the description of the existing theoretical model of the Sun and its main uncertainties and proceed with the discussion of the observational evidence for the anomaly. We conclude the review part by outlining the main approaches to solving the solar abundance problem investigated before. In the second part of the paper we consider the poorly studied before non-diffusive energy transport solutions to the problem. We calculate the additional energy flux inside the Sun evidenced by the combined data from helioseismology, spectroscopy and solar neutrino detection experiments. Our findings suggest that the solar abundance problem can be solved by a localized loss of energy near the radiative zone boundary and a gain of approximately the same amount of energy inside the solar core ( $0.1 R_{⊙} ≲ r ≲ 0.3 R_{⊙}$ ). We show that if the localized loss of energy is associated with the resonant emission of transversely polarized hidden photons, the kinetic mixing parameter required does not contradict any of the existing constraints, the ones from the Sun being relaxed as long as the energy loss is compensated by energy deposition inside the core. We introduce then the light dark fermions coupled to hidden photons and discuss their interactions with the solar plasma. We find the distribution of these dark particles inside the inner part of the radiative zone which is required to provide the necessary heating of the core.
↳ astro-ph.SRhep-phJCAP(2020)·5 citations
26*
Evidence for a Vast Prograde Stellar Stream in the Solar Vicinity
Lina Necib🇺🇸 · Bryan Ostdiek🇺🇸 · Mariangela Lisanti🇺🇸 · Timothy Cohen🇺🇸 · Marat Freytsis🇮🇱 · Shea Garrison-Kimmel🇺🇸 · Philip F. Hopkins🇺🇸 · Andrew Wetzel🇺🇸 · Robyn Sanderson🇺🇸
Massive dwarf galaxies that merge with the Milky Way on prograde orbits can be dragged into the disk plane before being completely disrupted. Such mergers can contribute to an accreted stellar disk and a dark matter disk. We present evidence for Nyx, a vast new stellar stream in the vicinity of the Sun, that may provide the first indication that such an event occurred in the Milky Way. We identify about 500 stars that have coherent radial and prograde motion in this stream using a catalog of accreted stars built by applying deep learning methods to the second Gaia data release. Nyx is concentrated within $\pm 2$ kpc of the Galactic midplane and spans the full radial range studied (6.5-9.5 kpc). The kinematics of Nyx stars are distinct from those of both the thin and thick disk. In particular, its rotational speed lags the disk by $\sim 80$ km/s and its stars follow more eccentric orbits. A small number of Nyx stars have chemical abundances or inferred ages; from these, we deduce that Nyx stars have a peak metallicity of [Fe/H] $\sim - 0.5$ and ages $\sim$ 10-13 Gyr. Taken together with the kinematic observations, these results strongly favor the interpretation that Nyx is the remnant of a disrupted dwarf galaxy. To further justify this interpretation, we explicitly demonstrate that metal-rich, prograde streams like Nyx can be found in the disk plane of Milky Way-like galaxies using the FIRE hydrodynamic simulations. Future spectroscopic studies will be able to validate whether Nyx stars originate from a single progenitor.
↳ astro-ph.GAastro-ph.COhep-phNature Astron.(2022)·61 citations
27*
A New Dual System For The Fundamental Units, including and going beyond the newly revised SI
Pierre Fayet🇫🇷
We propose a new system for the fundamental units, which includes and goes beyond the present redefinition of the SI, by choosing also $c = ℏ = 1$ . By fixing $c = c_{\circ}$ m/s = 1, $ℏ = ℏ_{\circ}$ Js = 1 and $μ_{\circ} = μ_{\circ}$ N/A $^{2}$ = 1, it allows us to define the metre, the joule, and the ampere as equal to (1/299 792 458) s, $(1/ ℏ_{\circ} = .948... \times 1 0^{34}) s^{- 1}$ and $μ_{\circ} N = μ_{\circ} c_{\circ} / ℏ_{\circ} s^{- 1} = 1.890... \times 1 0^{18} s^{- 1}$ . It presents at the same time the advantages and elegance of a system with $ℏ = c = μ_{\circ} = ϵ_{\circ} = k = N_{A} = 1$ , where the vacuum magnetic permeability, electric permittivity, and impedance are all equal to 1. All units are rescaled from the natural ones and proportional to the s, s $^{- 1}$ , s $^{- 2}$ , ... or just 1, as for the coulomb, ohm and weber, now dimensionless. The coulomb is equal to $μ_{\circ} c_{\circ} / ℏ_{\circ} = 1.890... \times 1 0^{18}$ , and the elementary charge to $e = 1.602... \times 1 0^{- 19} C = 4 π α = .3028...$ . The ohm is equal to $1/ μ_{\circ} c_{\circ}$ so that the impedance of the vacuum is $Z_{\circ} = 376.730...Ω = 1$ . The volt is $1/ μ_{\circ} c_{\circ} ℏ_{\circ} s^{- 1} = 5.017... \times 1 0^{15} s^{- 1}$ , and the tesla $c_{\circ}$ V/m = $c_{\circ}^{3} / μ_{\circ} ℏ_{\circ} s^{- 2} = 4.509... \times 1 0^{32} s^{- 2}$ . The weber is $1/ μ_{\circ} c_{\circ} ℏ_{\circ} = 5.017... \times 1 0^{15}$ . $K_{J} = 483 597.$ ... GHz/V $= e / π =$ .09639..., and $R_{K} = 25 812. ... Ω = 1/2 α ≃ 68.518$ . One can also fix $e$ = 1.602 176 634 $\times 1 0^{- 19}$ C, at the price of adjusting the coulomb and all electrical units with $μ_{\circ} = 4 π \times 1 0^{- 7} η^{2}$ where $η^{2}, \propto α$ , is very close to 1.
↳ physics.gen-phhep-phComptes Rendus Physique(2019)·0 citations

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