Tue·Nov 19, 2019Tuesday·November 19, 2019

1. 01*

   Calculating the angle between jet axes

   Pedro Cal🇳🇱 · Duff Neill🇺🇸 · Felix Ringer🇺🇸 · Wouter J. Waalewijn🇳🇱

   We study the angle between i) the standard jet axis, ii) the axis of a jet which has been groomed using soft drop, with reduced sensitivity to soft radiation, iii) the jet axis obtained with the winner-take-all recombination scheme, which is insensitive to soft radiation at leading power. We calculate the distributions for these angles at next-to-leading logarithmic accuracy, including non-global logarithms. The angle between the standard and groomed jet axis directly probes soft wide-angle radiation, leading to a novel factorization formula. This angle is also very sensitive to nonperturbative physics, which is directly connected to nonperturbative contribution to the rapidity anomalous dimension for transverse momentum distributions. Comparing our predictions to Pythia we find good agreement, and we foresee applications to jet substructure in proton-proton and heavy ion collisions.

   hep-phhep-exnucl-thJHEP(2020)·42 citations
2. 02*

   Strongly coupled theories beyond the Standard Model

   Antonio Dobado🇪🇸 · Domènec Espriu🇪🇸

   This article presents a number of technical tools and results that may be instrumental to discern the nature of the Higgs particle. In scenarios where an additional strongly interacting sector is present in the electroweak theory resulting in a composite Higgs and longitudinal components of the massive gauge bosons, unitarity, analyticity and related techniques will be crucial to understand the properties of such a sector. The situation today may be reminiscent of the pre-QCD days: a strongly interacting theory governs the short-distances, but we have only access to long-distance experiment involving Nambu-Goldstone or pseudo Nambu-Goldstone bosons. Like in those days we can only rely on symmetry and general properties of field theory. Luckily, unlike in the pre-QCD days, we have now a much clearer idea of what we may be after. After presenting a classification of the various types of effective theories, we establish the criteria as to under which conditions different representations are possible and their equivalence. We discuss in detail the implications of analyticity, causality and unitarity; describe various unitarization methods and establish the properties of dynamically generated resonances and form factors. The relation to effective Lagrangians with explicit resonances is explained in the context of beyond the Standard Model (BSM) physics and the Higgs effective field theory (HEFT). We discuss how various BSM models may be reduced to the HEFT as well as implications from holography and lattice studies in establishing BSM phenomenology. The methods presented are then applied to various processes relevant to disentangle the existence and nature of an extended electroweak symmetry breaking sector visible in $VV$ fusion: two-Higgs production, vector resonances, $\gamma \gamma$ physics and top-antitop production.

   hep-phPPNP(2020)·30 citations
3. 03*

   The ratio ${\rho }_{\bar{p}p}^{pp}(s)$ in Froissaron and Maximal Odderon approach

   E. Martynov🇺🇦 · G. Tersimonov🇺🇦

   The ratios ${\rho }_{\bar{p}p}^{pp}(s)$ of the real to the imaginary part of forward elastic $pp$ and $\bar{p}p$ scattering amplitudes at very high energies are considered in the models with rising total cross-sections and its difference. It is shown from the dispersion relations for $pp$ and $\bar{p}p$ scattering amplitudes that in the Froissaron and Maximal Odderon approach the ratios do not vanish asymptotically and they have the opposite signs for $pp$ and $\bar{p}p$ scattering.

   hep-phPRD(2019)·2 citations
4. 04*

   History of Neutrino Magnetic Moment

   Jihn E. Kim🇰🇷

   In this historic Lomonosov conference on the occasion of 150 year anniversary of the Mendeleev's periodic table, I present the history of neutrino magnetic moment. It was first thought by Wolfgang Pauli and its magnitude was calculated during the gauge theory era.

   hep-phastro-ph.SR4 citations
5. 05*

   Longitudinal structure function from the parton parameterization

   B.Rezaei🇮🇷 · G.R.Boroun🇮🇷

   We present a set of formulas to extract the longitudinal structure function from the proton structure function and its derivatives with respect to lnQ2 in the next-to-next-to-leading order of the perturbative theory at low x based on a hard poemron exchange. The behavior of the DIS cross section ratio R(x;Q2) and the ratio FL(x;Q2)=F2(x;Q2) studied and compared with the experimental data, also these behaviors controlled by the color dipole model bound. These results show a good agreement with the DIS experimental data throughout the low values of x. These results within the next-to-next-to-leading order approximation at very low x can be applied in the LHeC region for analyses of ultra-high energy processes.

   hep-phEPJA(2020)·12 citations
6. 06*

   Curious Link of Exclusive and Inclusive CPV in Charmless 3-body B+ Decays

   George W.-S. Hou🇹🇼

   The LHCb experiment has measured CP violation (CPV) across the Dalitz plot of charmless decays of B+ mesons to 3 charged tracks, namely in K{\pi}{\pi}, KKK, {\pi}{\pi}{\pi} and {\pi}KK final states, with strikingly large CPV that vary strongly with Dalitz variables. Identifying these processes with b -> sqq(bar), sss(bar) and b -> dqq(bar), dss(bar), where q = u, d, then the "sum rule" that requires two-loop absorptive parts by unitarity works well for inclusive b -> s CPV, but less well for inclusive b -> d case. We elucidate the situation, and argue that the 30 year old unitarity/CPT argument is valid to this day, while affirming quark-hadron duality.

   hep-phhep-ex3 citations
7. 07*

   Evaluation of the ${\theta }_K$ and the Mixing angle ${\theta }_{h_1}$

   Ya Gao🇨🇳 · Yateng Zhang🇨🇳 · Bo Zheng🇨🇳 · Zhen-Hua Zhang🇨🇳 · Wenbiao Yan🇨🇳 · Xiaohua Li🇨🇳

   The ${\theta }_K$ has been re-evaluated via mass relations and latest experimental results, meanwhile, the $M_{K_{1B}}$ also be obtained. Based on the singlet-octet mixing model and quark-flavor mixing model, the ${\theta }_{h_1}$ has been recalculated with a modified formula, by inputting $M_{K_{1B}}$ instead of ${\theta }_K$. The values are calculated to be $|{\theta }_K|=(42.6\pm 2.2{)}^{\circ }$, $M_{K_{1B}}=1333.9\pm 4.6\mathrm{MeV}/c^2$ and ${\theta }_{h_1}=29.5\pm 2.0^{\circ }$. Using these calculations as input, we predict that the branching fraction of $J/\psi \to {\eta }^{\prime }(\eta )h_1(1170)$ is about one order higher than that of $J/\psi \to {\eta }^{\prime }(\eta )h_1(1415)$, which can be measured in future experiments to test the validity of these two models.

   hep-phhep-ex3 citations
8. 08*

   Particle physics model of curvaton inflation in a stable universe

   Zoltán Péli🇭🇺 · István Nándori🇭🇺 · Zoltán Trócsányi🇭🇺

   We investigate a particle physics model for cosmic inflation based on the following assumptions: (i) there are at least two complex scalar fields; (ii) the scalar potential is bounded from below and remains perturbative up to the Planck scale; (iii) we assume slow-roll inflation with maximally correlated adiabatic and entropy fluctuations 50--60 e-folds before the end of inflation. The energy scale of the inflation is set automatically by the model. Assuming also at least one massive right handed neutrino, we explore the allowed parameter space of the scalar potential as a function of the Yukawa coupling of this neutrino.

   hep-phastro-ph.COhep-thPRD(2020)·10 citations
9. 09*

   QGP droplet formation in small asymmetric collision systems

   Thomas A. Trainor🇺🇸

   The journal Nature recently published a letter titled "Creating small circular, elliptical, and triangular droplets of quark-gluon plasma" [1]. The basis for that claim is a combination of measured Fourier amplitudes $v_2$ and $v_3$ from collision systems $p$-Au, $d$-Au and $h$-Au (helion $h$ is the nucleus of atom ${}^3$He), Glauber Monte Carlo estimates of initial-state transverse collision geometries for those systems and hydro Monte Carlo descriptions of the $v_n$ data. Correspondence between hydro $v_n$ trends and data trends is interpreted as confirmation of "collectivity" occurring in the small collision systems, further interpreted to indicate QGP formation. QGP formation in small systems runs counter to pre-RHIC theoretical assumptions that QGP formation should require large collision systems (e.g. central A-A collisions). There is currently available a broad context of experimental data from $p$-$p$, A-A and $p$-Pb collisions at the RHIC and LHC against which the validity of the Nature letter claims may be evaluated. This talk provides a summary of such results and their implications. [1] Nature Phys. 15, no. 3, 214 (2019).}

   hep-phnucl-thEPJ Web Conf.(2020)·1 citation
10. 10*

    Gauge Dependences of Higher-Order Corrections to NMSSM Higgs Boson Masses and the Charged Higgs Decay $H^{\pm }\to W^{\pm }{h}_i$

    T.N. Dao🇻🇳 · L. Fritz🇨🇭 · M. Krause🇩🇪 · M. Muhlleitner🇩🇪 · S. Patel🇩🇪

    In this paper we compute the electroweak corrections to the charged Higgs boson decay into a $W$ boson and a neutral Higgs boson in the CP-conserving NMSSM. We calculate the process in a general $R_{\xi }$ gauge and investigate the dependence of the loop-corrected decay width on the gauge parameter $\xi$. The gauge dependence arises from the mixing of different loop orders. Phenomenology requires the inclusion of mass and mixing corrections to the external Higgs bosons in order to match the experimentally measured mass values. As a result, we move away from a strict one-loop calculation and consequently mix orders in perturbation theory. Moreover, determination of the loop-corrected masses in an iterative procedure also results in the mixing of different loop orders. Gauge dependence then arises from the mismatch with tree-level Goldstone boson couplings that are applied in the loop calculation, and from the gauge dependence of the loop-corrected masses themselves. We find that the gauge dependence is significant.

    hep-phEPJC(2020)·15 citations
11. 11*

    Phenomenological study of neutrino mass, dark matter and baryogenesis within the framework of minimal extended seesaw

    Pritam Das🇮🇳 · Mrinal Kumar Das🇮🇳 · Najimuddin Khan🇮🇳

    We study a model of neutrino and dark matter within the framework of a minimal extended seesaw. This framework is based on $A_4$ flavor symmetry along with the discrete $Z_4$ symmetry to stabilize the dark matter and construct desired mass matrices for neutrino mass. We use a non-trivial Dirac mass matrix with broken $\mu -\tau$ symmetry to generate the leptonic mixing. A non-degenerate mass structure for right-handed neutrinos is considered to verify the observed baryon asymmetry of the Universe via the mechanism of thermal Leptogenesis. The scalar sector is also studied in great detail for a multi-Higgs doublet scenario, considering the lightest $Z_4$-odd as a viable dark matter candidate. A significant impact on the region of DM parameter space, as well as in the fermionic sector, are found in the presence of extra scalar particles.

    hep-phJHEP(2020)·23 citations
12. 12*

    Bound states and perturbation theory

    Paul Hoyer🇫🇮

    A perturbative expansion for QED and QCD bound states is formulated in $A^0=0$ gauge. The constituents of each Fock state are bound by their instantaneous interaction. In QCD an O(${\alpha }_s^0$) confining potential arises from a homogeneous solution of Gauss' constraint. The potential is uniquely determined by the QCD action, up to a universal scale. The Cornell potential is reproduced for quarkonia, and corresponding ones found for higher Fock states, baryons and glueballs.

    hep-phPoS(2019)·0 citations
13. 13*

    Excitation functions of related parameters from transverse momentum (mass) spectra in high energy collisions

    Li-Li Li🇨🇳 · Fu-Hu Liu🇨🇳 · Muhammad Waqas🇨🇳 · Rasha Al-Yusufi🇨🇳 · Altaf Mujear🇨🇳

    Transverse momentum (mass) spectra of positively and negatively charged pions, positively and negatively charged kaons, protons and antiprotons produced at mid-(pseudo)rapidity in various collisions at high energies are analyzed in this work. The experimental data measured in central gold-gold, central lead-lead, and inelastic proton-proton collisions by several international collaborations are studied. The (two-component) standard distribution is used to fit the data and extract the excitation function of effective temperature. Then, the excitation functions of kinetic freeze-out temperature, transverse flow velocity, and initial temperature are obtained. In the considered collisions, the four parameters increase with the increase of collision energy in general, and the kinetic freeze-out temperature appears the trend of saturation at the top Relativistic Heavy Ion Collider and the Large Hadron Collider.

    hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2020)·15 citations
14. 14*

    Broken Democracy with Intermediate ${\mathbb{S}}_2\times {\mathbb{S}}_2$ Residual Symmetry and Random Perturbations

    Neil D. Barrie🇯🇵 · Shao-Feng Ge🇨🇳 · Tsutomu T. Yanagida🇨🇳

    The democratic mass matrix is an intriguing possibility for explaining the observed fermion mixings due to its inherent hierarchical mass eigenvalues and large mixing angles. Nevertheless, two of the three mass eigenvalues are zero if the flavor democracy is exact, in obvious contradiction with the experimental observations. One possibility is breaking the flavor democracy with anarchical perturbations as we proposed in an earlier work. However, even within the first two generations, the charged fermion masses are also hierarchical which may not be a coincidence. The democratic ${\mathbb{S}}_3^L\times {\mathbb{S}}_3^R$ symmetry of the three generations may first be broken down to an intermediate ${\mathbb{S}}_2^L\times {\mathbb{S}}_2^R$ symmetry among the first two generations to regulate the sequential hierarchies, followed by random perturbations, that generate the correct size of all measured observables. Unique predictions for neutrinoless double beta decay are also found.

    hep-phPLB(2020)·3 citations
15. 15*

    The Sun at TeV energies: gammas, neutrons, neutrinos and a cosmic ray shadow

    Miguel Gutiérrez🇪🇸 · Manuel Masip🇪🇸

    High energy cosmic rays reach the surface of the Sun and start showers with thousands of secondary particles. Most of them will be absorbed by the Sun, but a fraction of the neutral ones will escape and reach the Earth. Here we incorporate a new ingredient that is essential to understand the flux of these solar particles: the cosmic ray shadow of the Sun. We use Liouville's theorem to argue that the only effect of the solar magnetic field on the isotropic cosmic ray flux is to interrupt some of the trajectories that were aiming to the Earth and create a shadow. This shadow reveals the average solar depth crossed by cosmic rays of a given rigidity. The absorbed cosmic ray flux is then processed in the thin Solar surface and, assuming that the emission of neutral particles by low-energy charged particles is isotropic, we obtain (i) a flux of gammas that is consistent with Fermi-LAT observations, (ii) a flux of 100-300 neutrons/(year m^2) produced basically in the spallation of primary He nuclei, and (iii) a neutrino flux that is above the atmospheric neutrino background at energies above 0.1-0.6 TeV (depending on the solar phase and the zenith inclination). More precise measurements of the cosmic ray shadow and of the solar gamma flux, together with the possible discovery of the neutron and neutrino signals, would provide valuable information about the magnetic field, the cycle, and the interior of the Sun.

    hep-phastro-ph.HEAstropart.Phys.(2020)·15 citations
16. 16*

    Lorentz-Violating Running of Coupling Constants

    A. R. Vieira🇧🇷 · N. Sherrill🇺🇸

    We compute the full vacuum polarization tensor in the minimal QED extension. We find that its low-energy limit is dominated by the radiatively induced Chern-Simons-like term and the high-energy limit is dominated by the c-type coefficients. We investigate the implications of the high-energy limit for the QED and QCD running couplings. In particular, the QCD running offers the possibility to study Lorentz-violating effects on the parton distribution functions and observables such as the hadronic R ratio.

    hep-phhep-thCPT and Lorentz Symmetry, pp. 98-101 (202…·2 citations
17. 17*

    Lorentz Violation and Partons

    Nathan Sherrill🇺🇸

    A parton-model description of high-energy hadronic interactions in the presence of Lorentz violation is presented. This approach is used to study lepton-hadron and hadron-hadron interactions at large momentum transfer. Cross sections for deep inelastic scattering and the Drell-Yan process are calculated at first order for minimal and nonminimal Lorentz violation. Estimated bounds are placed using existing LHC and future US-based Electron-Ion Collider data.

    hep-ph0 citations
18. 18*

    On the Statistical Treatment of the Cabibbo Angle Anomaly

    Yuval Grossman🇺🇸 · Emilie Passemar🇺🇸 · Stefan Schacht🇺🇸

    We point out that testing the equality of the Cabibbo angle as extracted from $\Gamma (K\to \pi l\nu )$, the ratio $\Gamma (K\to l\nu )/\Gamma (\pi \to l\nu )$ and nuclear $\beta$ decays is not identical to a test of first row unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. The reason is that a CKM unitarity test involves only two parameters, while the degrees of freedom for the assessment of the goodness-of-fit of the universality of the Cabibbo angle entailed by the Standard Model (SM) is equal to the number of measurements minus one. Beyond the SM all different processes could in principle give different Cabibbo angles. Consequently, the difference between the two tests becomes relevant starting from three observables giving results for the Cabibbo angle that are in tension with each other. With current data, depending on the treatment of the nuclear $\beta$ decays, we find that New Physics is favored over the SM at $5.1\sigma$ or $3.6\sigma$ while CKM unitarity is rejected at $4.8\sigma$ or $3.0\sigma$, respectively. We argue that the best method to test the SM is to test the equality of the Cabibbo angle, because CKM unitarity is only one aspect of the SM.

    hep-phJHEP(2020)·90 citations
19. 19*

    Dynamical evolution of axion condensates under stimulated decays into photons

    Pierluca Carenza (Bari U. & INFN Bari)🇮🇹 · Alessandro Mirizzi (Bari U. & INFN Bari)🇮🇹 · Günter Sigl (II Inst. Theor. Phys., Hamburg U.)🇩🇪

    Dark matter axion condensates may experience stimulated decays into photon pairs. This effect has been often interpreted as a parametric resonance of photons from the axion-photon coupling, leading to an exponential growth of the photon occupation number in a narrow instability band. Most of the previous literature does not consider the possible evolution of the axion field due to the photon growth. We revisit this effect presenting a mean field solution of the axion-photon kinetic equations, in terms of number of photons and pair correlations. We study the limit of no axion depletion, recovering the known instability. Moreover, we extend the results including a possible depletion of the axion field. In this case we find that the axion condensate exhibits the behaviour of an inverted pendulum. We discuss the relevance of these effects for two different cases: an homogeneous axion field at recombination and a localized axion clump and discuss constraints that could result from the induced photon background.

    hep-phastro-ph.COPRD(2020)·52 citations
20. 20*

    $|V_{cb}|$ and $\gamma$ from $B$-mixing -- Addendum to "$B_s$ mixing observables and $|V_{td}/V_{ts}|$ from sum rules"

    Daniel King🇬🇧 · Matthew Kirk🇮🇹 · Alexander Lenz🇬🇧 · Thomas Rauh🇨🇭

    In this addendum to "$B_s$ mixing observables and $|V_{td}/V_{ts}|$ from sum rules" \cite{King:2019lal} we study the impact of the recent improvements in the theoretical precision of $B$ meson mixing onto CKM unitarity fits. Our key results are the most precise determination of the angle $\gamma ={\left(63.4\pm 0.9\right)}^{\circ }$ in the unitarity triangle and a new value for the CKM element $|V_{cb}|=(41.6\pm 0.7)\cdot 10^{-3}$.

    hep-phhep-exJHEP(2020)·18 citations
21. 21*

    Superradiance and the Spins of Black Holes from LIGO and X-ray binaries

    Nicolas Fernandez🇺🇸 · Akshay Ghalsasi🇺🇸 · Stefano Profumo🇺🇸

    Measurements of the spin of stellar mass black holes (BHs) are now possible both through LIGO observations of binary BH mergers and for BHs in X-ray binary systems. The spins of BHs as inferred from LIGO observations suggest that BH spins are on the lower end of what is expected for a ``flat'' distribution of spins, while those from BHs in X-ray binaries tend to be large. Superradiance, a process that can effectively reduce the spin of BHs before they merge, could explain the lower observed spins in binary BH mergers for a non self-interacting light boson. In this paper, we use Bayesian analysis to infer the posterior probability distribution for the mass of a light boson that could fit LIGO data. We also analyze spins of BHs from X-ray binaries, and find that the X-ray binary data can be explained by superradiance due to a light boson with large self-interactions. We infer the mass range for such a boson that is consistent with the X-ray binary data.

    hep-phastro-ph.COgr-qc34 citations
22. 22*

    Flavourful SMEFT likelihood for Higgs and electroweak data

    Adam Falkowski🇫🇷 · David Straub🇩🇪

    We perform an updated fit to LHC Higgs data and LEP electroweak precision tests in the framework of the Standard Model Effective Field Theory (SMEFT). We assume a generic structure of the SMEFT operators without imposing any flavour symmetries. The implementation is released as part of the public global SMEFT likelihood. This allows one to fit parameters of a broad class of new physics models to combined Higgs, electroweak, quark flavour, and lepton flavour observables.

    hep-phJHEP(2020)·72 citations
23. 23*

    Light Dark Matter and Superfluid He-4 from EFT

    Andrea Caputo🇪🇸 · Angelo Esposito🇨🇭 · Antonio D. Polosa🇮🇹

    We study the response of a He-4 detector to the interaction of sub-GeV dark matter using an effective field theory for the superfluid. We compute the lifetime of the phonon, which agrees with what known from standard techniques, hence providing an important check of the effective field theory. We then study the process of emission of two phonons, and show how its rate is much more suppressed than the phase space expectations; this is a consequence of the conservation of the current associated to the superfluid symmetries.

    hep-phastro-ph.COJ.Phys.Conf.Ser.(2020)·13 citations
24. 24*

    MeV-GeV $\gamma$-ray telescopes probing gravitino LSP with coexisting axino NLSP as dark matter in the $\mu \nu$SSM

    German A. Gomez-Vargas🇨🇱 · Daniel E. Lopez-Fogliani🇦🇷 · Carlos Munoz🇪🇸 · Andres D. Perez🇦🇷

    In $R$-parity violating supersymmetry, the gravitino as the lightest supersymmetric particle (LSP) is a good candidate for dark matter, with the interesting characteristic to be detectable through $\gamma$-ray telescopes. We extend this analysis considering an axino next-to-LSP (NLSP) as a coexisting dark matter particle contributing with a detectable signal in the $\gamma$-ray spectrum. The analysis is carried out in the framework of the $\mu \nu$SSM, which solves the $\mu$ problem reproducing simultaneously neutrino data only with the addition of right-handed neutrinos. We find that important regions of the parameter space can be tested by future MeV-GeV $\gamma$-ray telescopes through the line signal coming from the decay of the axino NLSP into photon-neutrino. In a special region, a double-line signal from axino NLSP and gravitino LSP is possible with both contributions detectable.

    hep-phastro-ph.HEAstropart.Phys.(2021)·21 citations
25. 25*

    Lepton-Proton Two-Photon Exchange in Chiral Perturbation Theory

    Pulak Talukdar🇮🇳 · Vanamali C. Shastry🇮🇳 · Udit Raha🇮🇳 · Fred Myhrer🇺🇸

    We use heavy baryon chiral perturbation theory to evaluate the two-photon exchange corrections to the low-energy elastic lepton-proton scattering at next-to-leading order accuracy, i.e., $\mathcal{O}(\alpha ,M^{-1})$, including a non-zero lepton mass. We consider the elastic proton intermediate state in the two-photon exchange together in the soft photon approximation. The infrared singular contributions are projected out using dimensional regularization. The resulting infrared singularity-free two-photon exchange contribution is in good numerical agreement with existing predictions based on standard diagrammatic soft photon approximation evaluations.

    ↳ nucl-thhep-phPRD(2020)·22 citations
26. 26*

    ${\Xi }^{-}t$ quasibound state instead of $\Lambda \Lambda nn$ bound state

    H. Garcilazo🇲🇽 · A. Valcarce🇪🇸 · J. Vijande🇪🇸

    We study the coupled $\Lambda \Lambda nn-{\Xi }^{-}pnn$ system to check whether the inclusion of channel coupling is able to bind the $\Lambda \Lambda nn$ system. We use a separable potential three-body model of the coupled $\Lambda \Lambda nn-{\Xi }^{-}pnn$ system as well as a variational four-body calculation with realistic interactions. Our results exclude the possibility of a $\Lambda \Lambda nn$ bound state by a large margin. However, we have found a ${\Xi }^{-}t$ quasibound state above the $\Lambda \Lambda nn$ threshold.

    ↳ nucl-thhep-phCPC(2020)·4 citations
27. 27*

    A charming ICECUBE discover?

    D. Fargion🇮🇹 · P.G. De Sanctis Lucentini🇷🇺 · M.Yu. Khlopov🇷🇺 · P. Oliva🇮🇹 · F. La Monaca🇮🇹 · P. Paggi🇮🇹

    Last two years high energy neutrino data are studied. The two recent tau neutrino double bang candidate are discussed within their detectability, noise and expected rate. The neutrino flavor distribution mainly favoring equal electron and muon presence, is reminded. The angular distribution of highest muon neutrino tracks is analyzed. Their horizontal strong anisotropy and their remarkable up-down asymmetry, with the absence of clustering, is noticed. The main persistent missing of astrophysical X,gamma sources (as GRB and AGN flaring source) and all the above signatures led us to suggest a dominance of prompt charmed (atmospheric) events able to pollute, to smear and to hide any minor astronomical presence.

    ↳ astro-ph.HEastro-ph.IMhep-phPoS(2019)·2 citations
28. 28*

    Probing Small Scale Primordial Power Spectrum with 21cm Line Global Signal

    Shintaro Yoshiura🇦🇺 · Keitaro Takahashi🇯🇵 · Tomo Takahashi🇯🇵

    We argue that the global signal of neutral hydrogen 21cm line can be a powerful probe of primordial power spectrum on small scales. Since the amplitude of small scale primordial fluctuations is important to determine the early structure formation and the timing when the sources of Lyman $\alpha$ photons are produced, they in turn affect the neutral hydrogen 21cm line signal. We show that the information of the position of the absorption trough can severely constrain the small scale amplitude of primordial fluctuations once astrophysical parameters relevant to the 21cm line signal are fixed. We also discuss how the uncertainties of astrophysical parameters affect the constraints.

    ↳ astro-ph.COgr-qchep-phPRD(2020)·21 citations
29. 29*

    Vector-boson condensates, spin-triplet superfluidity of paired neutral and charged fermions, and $3P_2$ pairing of nucleons

    D. N. Voskresensky🇷🇺

    After reminding of properties of the condensate of the complex scalar field in the external uniform magnetic field $H$ focus is made on the study of phases of the complex neutral vector boson fields coupled with magnetic field by the Zeeman coupling and phases of the charged vector boson fields. These systems may behave as nonmagnetic and ferromagnetic superfluids and ordinary and ferromagnetic superconductors. Response of the ferromagnetic superfluid and superconducting systems occupying half of space on the external uniform static magnetic field $H$ is thoroughly studied. Then the spin-triplet pairing of neutral fermions at conserved spin is considered. Novel phases are found. In external magnetic field the phase with zero mean spin proves to be unstable to the formation of a phase with a non-zero spin. For $H>H_{cr2}$ the spin-triplet pairing and ferromagnetic superfluidity continue to exist above the "old" phase transition critical temperature $T_{\mathrm{cr}}$. For a certain parameter choice ferromagnetic superfluid phases are formed already for $H=0$, characterized by an own magnetic field $h$. Formation of domains is discussed. Next, spin-triplet pairing of charged fermions is studied. Novel phases are found with a ferromagnetic superconductivity. Then, the 3P${}_2$ $nn$ pairing in neutron star matter is studied. Also a 3P${}_2$ $pp$ pairing is considered. Numerical estimates are performed in the BCS weak coupling limit and beyond it for the $3P_2$ $nn$ and $pp$ pairings, as well as for the 3S${}_1$ $np$ pairing.

    ↳ nucl-thcond-mat.supr-conhep-phPRD(2020)·6 citations
30. 30*

    Neutrino Production Associated with Late Bumps in Gamma-Ray Bursts and Potential Contribution to Diffuse Flux at IceCube

    Gang Guo🇹🇼 · Yong-Zhong Qian🇺🇸 · Meng-Ru Wu🇹🇼

    IceCube has detected many TeV--PeV neutrinos, but their astrophysical origins remain largely unknown. Motivated by the observed late-time X-ray/optical bumps in some gamma-ray bursts (GRBs), we examine the correlation between IceCube neutrinos and GRBs allowing delayed neutrinos $\sim$days after the prompt gamma rays. Although we have not found any definitive correlation, up to $\sim$10\% of the events observed so far at IceCube may have been neutrinos produced by the late-time GRB activities at $\sim$1 day. Assuming a connection between some IceCube events and the late GRB bumps, we show in a model-independent way that GRB sites capable of producing late $\sim$PeV neutrinos should be nonrelativistic or mildly relativistic. We estimate the diffuse neutrino flux from such sources and find that they can possibly account for a few IceCube events. Future observations of high-energy neutrinos and late-time GRB afterglows can further test the above proposed connection.

    ↳ astro-ph.HEhep-phApJ(2020)·7 citations
31. 31*

    Hydrodynamics from free-streaming to thermalization and back again

    Chandrodoy Chattopadhyay🇺🇸 · Ulrich W. Heinz (Ohio State University)🇺🇸

    We study the evolution of the Knudsen and Reynolds numbers in (0+1)-dimensionally expanding fluids with Bjorken symmetry for systems whose microscopic mean free path rises more quickly with time than usually assumed. This allows us to explore within a simple 1-dimensional model the transition from initially thermalizing to ultimately decoupling dynamics. In all cases studied the dynamics is found to be controlled by hydrodynamic attractors for both the Knudsen and Reynolds numbers whose trajectories undergo characteristic changes as the dynamics changes from thermalizing to decoupling.

    ↳ nucl-thhep-phPLB(2020)·49 citations
32. 32*

    Imprints of the Early Universe on Axion Dark Matter Substructure

    Nikita Blinov🇺🇸 · Matthew J. Dolan🇦🇺 · Patrick Draper🇺🇸

    Despite considerable experimental progress large parts of the axion-like particle (ALP) parameter space remain difficult to probe in terrestrial experiments. In some cases, however, small-scale structure of the ALP dark matter (DM) distribution is strongly enhanced, offering opportunities for astrophysical tests. Such an enhancement can be produced by a period of pre-nucleosynthesis early matter domination (EMD). This cosmology arises in many ultraviolet completions and generates the correct relic abundance for weak coupling $f_a\sim 10^{16}$ GeV, ALP masses in the range $10^{-13}$ eV $<m_a<1$ eV, and without fine-tuning of the initial misalignment angle. This range includes the QCD axion around $10^{-9}-10^{-8}$ eV. EMD enhances the growth of ALP small-scale structure, leading to the formation of dense ALP miniclusters. We study the interplay between the initial ALP oscillation, reheating temperature, and effective pressure to provide analytic estimates of the minicluster abundance and properties. ALP miniclusters in the EMD cosmology are denser and more abundant than in $\Lambda$CDM. While enhanced substructure generically reduces the prospects of direct detection experiments, we show that pulsar timing and lensing observations can discover these minihalos over a large range of ALP masses and reheating temperatures.

    ↳ astro-ph.COhep-phhep-thPRD(2020)·67 citations
33. 33*

    Search for dark matter induced de-excitation of ${}^{180}$Ta${}^{\mathrm{m}}$

    Björn Lehnert🇺🇸 · Harikrishnan Ramani🇺🇸 · Mikael Hult🇧🇪 · Guillaume Lutter🇧🇪 · Maxim Pospelov🇨🇦 · Surjeet Rajendran🇺🇸 · Kai Zuber🇩🇪

    Weak-scale dark matter particles, in collisions with nuclei, can mediate transitions between different nuclear energy levels. In particular, owing to sizeable momentum exchange, dark matter particles can enable de-excitation of nuclear isomers that are extremely long lived with respect to regular radioactive decays. In this paper, we utilize data from a past experiment with ${}^{180}$Ta${}^{\mathrm{m}}$ to search for $\gamma$-lines that would accompany dark matter induced de-excitation of this isomer. Non-observation of such transitions above background yields the first direct constraint on the lifetime of ${}^{180}$Ta${}^{\mathrm{m}}$ against DM-initiated transitions: $T_{1/2}>1.3\times 10^{14}$~a at 90\% C.I. Using this result, we derive novel constraints on dark matter models with strongly interacting relics, and on models with inelastic dark matter particles. Existing constraints are strengthened by this independent new method. The obtained limits are also valid for the Standard Model $\gamma$-decay of ${}^{180}$Ta${}^{\mathrm{m}}$.

    ↳ astro-ph.COhep-exhep-phnucl-ex+1PRL(2020)·39 citations
34. 34*

    Evolution of High-energy Particle Distribution in Supernova Remnants

    Houdun Zeng🇨🇳 · Yuliang Xin🇨🇳 · Qi Fu🇨🇳 · Siming Liu🇨🇳

    The spectra fits to a sample of 34 supernova remnants (Zeng et al., 2019) are updated. $\gamma$-ray spectra of 20 supernova remnants (SNRs) with a soft TeV spectrum are further analyzed. We found that 17 of them can be fitted in the hadronic scenario with a single power-law ion distribution with an index of $\sim$ 2.6, which is significantly softer than the ion distribution inferred from $\gamma$-ray observations of star-burst galaxies. If Galactic cosmic rays are mostly produced by SNRs, this result suggests that SNRs in star-burst galaxies may never reach the phase with a soft $\gamma$-ray spectra or escape of high-energy particles from SNRs before they reach this phase with a soft $\gamma$-ray spectrum dominates the contribution of SNRs to Galactic cosmic rays.

    ↳ astro-ph.HEhep-ph0 citations
35. 35*

    Transport coefficients for the hot quark-gluon plasma at finite chemical potential ${\mu }_B$

    Olga Soloveva🇩🇪 · Pierre Moreau🇩🇪 · Elena Bratkovskaya🇩🇪

    We calculate transport coefficients of the quark-gluon plasma (QGP) within the dynamical quasiparticle model (DQPM) by explicitly computing the parton interaction rates as a function of temperature $T$ and baryon chemical potential ${\mu }_B$ on the basis of the DQPM couplings and partonic propagators. The latter are extracted from lattice QCD by matching the equation of state, entropy density and energy density at ${\mu }_B$= 0. For baryon chemical potentials $0\le {\mu }_B\le 500MeV$ we employ a scaling Ansatz for the effective coupling which was shown before to lead to thermodynamic consistent results in this range. We compute the ratio of the shear and bulk viscosities to the entropy density, i.e. $\eta /s$ and $\zeta /s$, the electric conductivity ${\sigma }_0/T$ as well as the baryon diffusion coefficient ${\kappa }_B$ and compare to related approaches from the literature. We find that the ratios $\eta /s$ and $\zeta /s$ as well as ${\sigma }_0/T$ are in accord with the results from lattice QCD at ${\mu }_B$=0 and only weakly depend on the ratio $T/T_c({\mu }_B)$ where $T_c({\mu }_B)$ denotes the critical temperature at finite baryon chemical potential.

    ↳ nucl-thhep-phPRC(2020)·67 citations
36. 36*

    Towards the understanding of $Z_c(3900)$ from lattice QCD

    Chuan Liu🇨🇳 · Liuming Liu🇨🇳 · Ke-Long Zhang🇨🇳

    Within the framework of three-channel Ross-Shaw effective range theory, we derive the constraints among different parameters of the theory in the case of a narrow resonance close to the threshold of the third channel, which is relevant for the resonance-like structure $Z_c(3900)$. The usage of these constraint relations, together with the multi-channel Lüscher formula in lattice QCD calculations are also discussed and the strategies are outlined.

    ↳ hep-lathep-phPRD(2020)·12 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.