Mon·Nov 2, 2020Monday·November 2, 2020

1. 01*

   Proton em form factors data are in disagreement with new ${\sigma }_{tot}(e^{+}{e}^{-}\to p\bar{p})$ measurements

   Anna Zuzana Dubnickova🇸🇰 · Stanislav Dubnicka🇸🇰

   Till now almost 50 different data collections on the proton and neutron electromagnetic form factors, also on their ratios, exist. On the other hand, recently new very precise data on ${\sigma }_{tot}(e^{+}{e}^{-}\to p\bar{p})$ from threshold up to cca 13.5 GeV${}^2$ have been obtained by BESIII Collaboration using the initial state radiation technique with an undetected photon at the BEPcII collider. In this paper a consistency of the ${\sigma }_{tot}(e^{+}{e}^{-}\to p\bar{p})$ data with the proton form factors behaviors is investigated, first when the latter are obtained in the analysis of the proton and neutron form factors data together by the advanced nucleon electromagnetic structure Unitary and Analytic model, and then, as the neutron data are considered to be not very precise, obtained in the analysis of only the proton form factors data in spacelike and timelike regions by the advanced proton electromagnetic structure Unitary and Analytic model. In both cases one finds the new ${\sigma }_{tot}(e^{+}{e}^{-}\to p\bar{p})$ data to be inconsistent with the curves of ${\sigma }_{tot}(e^{+}{e}^{-}\to p\bar{p})$ calculated by the proton electric and magnetic form factors behaviors found in both analyses.

   hep-ph5 citations
2. 02*

   Ambiguities in the definition of local spatial densities in light hadrons

   Robert L. Jaffe🇺🇸

   The relationship between the matrix element of a local operator and the Fourier transform of the associated form factor fails for systems such as the nucleon where its intrinsic size is of order its Compton wavelength. Although one can conceive of an intrinsic charge density distribution in the proton, there does not seem to be an unambiguous way to define, compute, or measure it precisely.

   hep-phhep-latnucl-exnucl-thPRD(2021)·83 citations
3. 03*

   Non-local Non-Abelian Gauge Theory: Conformal Invariance and $\beta$-function

   Anish Ghoshal🇮🇹 · Anupam Mazumdar🇳🇱 · Nobuchika Okada🇺🇸 · Desmond Villalba🇺🇸

   This paper focuses on extending our previous discussion of an Abelian U(1) gauge theory involving infinite derivatives to a non-Abelian SU(N) case. The renormalization group equation (RGEs) of the SU(N) gauge coupling is calculated and shown to reproduce the local theory $\beta$-function in the limit of the non-local scale M $\to \infty$. Interestingly, the gauge coupling stops its running beyond the scale $M$, approaching an asymptotically conformal theory.

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

   The Podolsky propagator in gap and bound-state equations

   Bruno El-Bennich🇧🇷 · G. E. R. Zambrano🇨🇴 · Eduardo Rojas🇨🇴

   Based on the Generalized Quantum Electrodynamics expression for the Podolsky propagator, which preserves gauge invariance for massive photons, we propose a model for the massive gluon propagator that reproduces well-known features of established strong-interaction models in the framework of the Dyson-Schwinger equation. By adjusting the Podolsky mass and the coupling strength we thus construct a model with simple analytical properties known from perturbative theory, yet well suited to describe a confining interaction. We obtain solutions of the Dyson-Schwinger equation for the quark at space-like momenta on the real axis as well as on the complex plane and solving the bound-state problem with the Bethe-Salpeter equation yields masses and weak decay constants of the $\pi ,K$ and ${\eta }_c$ in excellent agreement with experimental values, while the $D$ and $D_s$ are reasonably well described. The analytical simplicity of this effective interaction has the potential to be useful for phenomenological applications and may facilitate calculations in Minkowski space.

   hep-phPRD(2021)·8 citations
5. 05*

   Semileptonic Decay of ${\Omega }_c^0\to {\Xi }^{-}{l}^{+}{\nu }_l$ From Light-Cone Sum Rules

   Hui-Hui Duan🇨🇳 · Yong-Lu Liu🇨🇳 · Ming-Qiu Huang🇨🇳

   The weak decay process of ${\Omega }_c$ to $\Xi$ is calculated in the method of QCD light-cone sum rule. The decay width of ${\Omega }_c^0\to {\Xi }^{-}{l}^{+}{\nu }_l$ and its decay branching ratio are also calculated with the form factors from this work's calculation. To the twist-6 distribution amplitudes, the form factors $f_1=0.66\pm 0.02,f_2=-0.76\pm 0.03,g_1=0.06\pm 0.01$ and $g_2=-0.44\pm 0.01$ are given at zero recoil point. The result of the semileptonic decay width of ${\Omega }_c^0\to {\Xi }^{-}{l}^{+}{\nu }_l$ is $\Gamma =(7.51\pm 0.36)\times 10^{-15}\mathrm{GeV}$ , and the prediction of the decay branching ratio $Br({\Omega }_c^0\to {\Xi }^{-}{l}^{+}{\nu }_l)=(3.06\pm 0.15)\times 10^{-3}$. These results fit well with other works, and the decay width and branching ratio are improved. This not too small branching ratio gives a good direction to explore this decay channel in the future experiments.

   hep-phEPJC(2021)·4 citations
6. 06*

   Scalar neutrino dark matter in BLMSSM

   Ming-Jie Zhang🇨🇳 · Shu-Min Zhao🇨🇳 · Xing-Xing Dong🇨🇳 · Zhong-Jun Yang🇨🇳 · Tai-Fu Feng🇨🇳

   BLMSSM is the extension of the minimal supersymmetric standard model(MSSM). Its local gauge group is $SU(3{)}_C\times SU(2{)}_L\times U(1{)}_Y\times U(1{)}_B\times U(1{)}_L$. Supposing the lightest scalar neutrino is dark matter candidate, we study the relic density and the spin independent cross section of sneutrino scattering off nucleon. We calculate the numerical results in detail and find suitable parameter space. The numerical discussion can confine the parameter space and provide a reference for dark matter research.

   hep-phCPC(2021)·1 citation
7. 07*

   Symmetric reduction of high-multiplicity one-loop integrals and maximal cuts

   Guy R. Jehu🇮🇪

   We derive useful reduction formulae which express one-loop Feynman integrals with a large number of external momenta in terms of lower-point integrals carrying easily derivable kinematic coefficients which are symmetric in the external momenta. These formulae apply for integrals with at least two more external legs than the dimension of the external momenta, and are presented in terms of two possible bases: one composed of a subset of descendant integrals with one fewer external legs, the other composed of the complete set of minimally-descendant integrals with just one more leg than the dimension of external momenta. In 3+1 dimensions, particularly compact representations of kinematic invariants can be computed, which easily lend themselves to spinor-helicity or trace representations. The reduction formulae have a close relationship with D-dimensional unitarity cuts, and thus provide a path towards computing full (all-epsilon) expressions for scattering at arbitrary multiplicity.

   hep-phhep-thJHEP(2021)·2 citations
8. 08*

   Tentative sensitivity of future $0\nu \beta \beta$-decay experiments to neutrino masses and Majorana CP phases

   Guo-yuan Huang🇩🇪 · Shun Zhou🇨🇳

   In the near future, the neutrinoless double-beta ($0\nu \beta \beta$) decay experiments will hopefully reach the sensitivity of a few $\mathrm{meV}$ to the effective neutrino mass $|m_{\beta \beta }^{}|$. In this paper, we tentatively examine the sensitivity of future $0\nu \beta \beta$-decay experiments to neutrino masses and Majorana CP phases by following the Bayesian statistical approach. Provided experimental setups corresponding to the sensitivity of $|m_{\beta \beta }^{}|\simeq 1\mathrm{meV}$, the null observation of $0\nu \beta \beta$ decays in the case of normal neutrino mass ordering leads to a very competitive bound on the lightest neutrino mass $m_1^{}$. Namely, the $95\%$ credible interval turns out to be $1.6\mathrm{meV}\lesssim m_1^{}\lesssim 7.3\mathrm{meV}$ or $0.3\mathrm{meV}\lesssim m_1^{}\lesssim 5.6\mathrm{meV}$ when the uniform prior on $m_1^{}/\mathrm{eV}$ or on ${\log }_{10}^{}(m_1^{}/\mathrm{eV})$ is adopted. Moreover, one of two Majorana CP phases is strictly constrained, i.e., $140^{\circ }\lesssim \rho \lesssim 220^{\circ }$ for both priors of $m_1^{}$. In contrast, if a relatively worse sensitivity of $|m_{\beta \beta }^{}|\simeq 10\mathrm{meV}$ is assumed, the constraint becomes accordingly $0.6\mathrm{meV}\lesssim m_1^{}\lesssim 26\mathrm{meV}$ or $0\lesssim m_1^{}\lesssim 6.1\mathrm{meV}$, while two Majorana CP phases will be essentially unconstrained. In the same statistical framework, the prospects for the determination of neutrino mass ordering and the discrimination between Majorana and Dirac nature of massive neutrinos in the $0\nu \beta \beta$-decay experiments are also discussed. Given the experimental sensitivity of $|m_{\beta \beta }^{}|\simeq 10\mathrm{meV}$ (or $1\mathrm{meV}$), the strength of evidence to exclude the Majorana nature under the null observation of $0\nu \beta \beta$ decays is found to be inconclusive (or strong), no matter which of two priors on $m_1^{}$ is taken.

   hep-phhep-exJHEP(2021)·5 citations
9. 09*

   Discovery potential of FASER$\nu$ with contained vertex and through-going events

   Pouya Bakhti🇮🇷 · Yasaman Farzan🇮🇷 · Silvia Pascoli🇬🇧

   FASER$\nu$ is a newly proposed detector whose main mission is to detect the neutrino flux from the collision of the proton beams at the ATLAS Interaction Point (IP) during the run III of the LHC in 2022-2024. We show that this detector can also test certain beyond standard model scenarios, especially the ones in which the neutrino interaction with matter fields can produce new unstable particles decaying back into charged leptons. Models of this kind are motivated by the MiniBooNE anomaly. We show that, if the new physics involves multi-muon production by neutrinos scattering off matter fields, including the neutrino flux interactions in the rock before the detector in the analysis ({\it i.e.,} accounting for the through-going muon pairs) can significantly increase the effective detector mass and its sensitivity to new physics. We propose a concrete model that can give rise to such a multi-muon signal.

   hep-phhep-exJHEP(2021)·16 citations
10. 10*

    Exploring invisible neutrino decay at ESSnuSB

    Sandhya Choubey🇸🇪 · Monojit Ghosh🇸🇪 · Daniel Kempe🇸🇪 · Tommy Ohlsson🇸🇪

    We explore invisible neutrino decay in which a heavy active neutrino state decays into a light sterile neutrino state and present a comparative analysis of two baseline options, $540$km and $360$km, for the ESSnuSB experimental setup. Our analysis shows that ESSnuSB can put a bound on the decay parameter ${\tau }_3/m_3=2.64(1.68)\times 10^{-11}$s/eV for the baseline option of $360(540)$km at $3\sigma$. The expected bound obtained for $360$km is slightly better than the corresponding one of DUNE for a charged current (CC) analysis. Furthermore, we show that the capability of ESSnuSB to discover decay, and to measure the decay parameter precisely, is better for the baseline option of $540$km than that of $360$km. Regarding effects of decay in ${\delta }_{\mathrm{CP}}$ measurements, we find that in general the CP violation discovery potential is better in the presence of decay. The change in CP precision is significant if one assumes decay in data but no decay in theory.

    hep-phhep-exJHEP(2021)·32 citations
11. 11*

    DsixTools 2.0: The Effective Field Theory Toolkit

    Javier Fuentes-Martin🇩🇪 · Pedro Ruiz-Femenia🇪🇸 · Avelino Vicente🇪🇸 · Javier Virto🇪🇸

    $\mathtt{DsixTools}$ is a Mathematica package for the handling of the Standard Model Effective Field Theory (SMEFT) and the Low-energy Effective Field Theory (LEFT) with operators up to dimension six, both at the algebraic and numerical level. $\mathtt{DsixTools}$ contains a visually accessible and operationally convenient repository of all operators and parameters of the SMEFT and the LEFT. This repository also provides information concerning symmetry categories and number of degrees of freedom, and routines that allow to implement this information on global expressions (such as decay amplitudes and cross-sections). $\mathtt{DsixTools}$ also performs weak basis transformations, and implements the full one-loop Renormalization Group Evolution in both EFTs (with SM beta functions up to five loops in QCD), and the full one-loop SMEFT-LEFT matching at the electroweak scale.

    hep-phhep-exhep-lathep-thEPJC(2021)·135 citations
12. 12*

    Charged Lepton Flavor Violation in SU(5) SUSY GUT and MSSM + Type-I Seesaw Model

    Devidutta Gahan🇮🇳 · Ng. K. Francis🇮🇳

    Till today lepton flavor violation has not been observed in processes involving charged leptons. Hence, a search for it is under hot pursuit both in theories and experiments. In our current work, we investigate the rates of rare decay processes such as $\tau \to \mu \gamma$ in SU(5) SUSY GUT and found that it satisfies the current bound and is one order below the projected sensitivity. This gives a corroborative argument for the influence of the large top-Yukawa coupling at the GUT scale (${\lambda }_{tG}$) on flavor violating decay rates of leptons which are investigable at low energy electroweak scale $M_Z$. Secondly, we discuss the decay rates of $\mu \to e\gamma$ & $\tau \to \mu \gamma$ in MSSM with added right handed neutrino superfields. From this, we set bounds on $\tan \beta$ and further, we investigate the mass of ${\tilde{\chi }}_1^0$, the LSP, using the rates of LFV decays. In the calculations, the latest updated data from LHC, neutrino oscillation experiments and constraints on branching ratios from the MEG experiment have been used.

    hep-ph0 citations
13. 13*

    Deuteron Uncertainties in the Determination of Proton PDFs

    Richard D. Ball🇬🇧 · Emanuele R. Nocera🇳🇱 · Rosalyn L. Pearson🇬🇧

    We evaluate the uncertainties due to nuclear effects in global fits of proton parton distribution functions (PDFs) that utilise deep-inelastic scattering and Drell-Yan data on deuterium targets. To do this we use an iterative procedure to determine proton and deuteron PDFs simultaneously, each including the uncertainties in the other. We apply this procedure to determine the nuclear uncertainties in the SLAC, BCDMS, NMC and DYE866/NuSea fixed target deuteron data included in the NNPDF3.1 global fit. We show that the effect of the nuclear uncertainty on the proton PDFs is small, and that the increase in overall uncertainties is insignificant once we correct for nuclear effects.

    hep-phhep-exnucl-thEPJC(2021)·41 citations
14. 14*

    Magnetic field in relativistic heavy ion collisions: testing the classical approximation

    I. Danhoni🇧🇷 · F. S. Navarra🇧🇷

    It is believed that in non-central relativistic heavy ion collisions a very strong magnetic field is formed. There are several studies of the effects of this field, where $\vec{B}$ is calculated with the expressions of classical electrodynamics. A quantum field may be approximated by a classical one when the number of field quanta in each field mode is sufficiently high. This may happen if the field sources are intense enough. In heavy ion physics the validity of the classical treatment was not investigated. In this work we propose a test of the quality of the classical approximation. We calculate an observable quantity using the classical magnetic field and also using photons as input. If the results of both approaches coincide, this will be an indication that the classical approximation is valid. More precisely, we focus on the process in which a nucleon is converted into a delta resonance, which then decays into another nucleon and a pion, i.e., $N\to \Delta \to N^{\prime }\pi$. In ultra-peripheral relativistic heavy ion collisions this conversion can be induced by the classical magnetic field of one the ions acting on the other ion. Alternatively, we can replace the classical magnetic field by a flux of equivalent photons, which are absorbed by the target nucleons. We calculate the cross sections in these two independent ways and find that they differ from each other by $\simeq 10$ \% in the considered collision energy range. This suggests that the two formalisms are equivalent and that the classical approximation for the magnetic field is reasonable.

    hep-phPRC(2021)·9 citations
15. 15*

    Effect on Dark Matter Exclusion Limits from New Silicon Photoelectric Absorption Measurements

    Belina von Krosigk🇩🇪 · Matthew J. Wilson🇨🇦 · Chris Stanford🇺🇸 · Blas Cabrera🇺🇸 · Robert Calkins🇺🇸 · Daniel Jardin🇺🇸 · Noah A. Kurinsky🇺🇸 · Francisco Ponce🇺🇸 · Chih-Pan Wu🇨🇦

    Recent breakthroughs in cryogenic silicon detector technology allow for the observation of single electron-hole pairs released via particle interactions within the target material. This implies sensitivity to energy depositions as low as the smallest band gap, which is $\sim 1.2$ eV for silicon, and therefore sensitivity to eV/$c^2$-scale bosonic dark matter and to thermal dark matter at masses below 100 MeV/$c^2$. Various interaction channels that can probe the lowest currently accessible masses in direct searches are related to standard photoelectric absorption. In any of these respective dark matter signal models any uncertainty on the photoelectric absorption cross section is propagated into the resulting exclusion limit or into the significance of a potential observation. Using first-time precision measurements of the photoelectric absorption cross section in silicon recently performed at Stanford University, this article examines the importance having accurate knowledge of this parameter at low energies and cryogenic temperatures for these dark matter searches.

    ↳ hep-exhep-phPRD(2021)·6 citations
16. 16*

    Scattering Amplitudes and the Navier-Stokes Equation

    Clifford Cheung🇺🇸 · James Mangan🇺🇸

    We explore the scattering amplitudes of fluid quanta described by the Navier-Stokes equation and its non-Abelian generalization. These amplitudes exhibit universal infrared structures analogous to the Weinberg soft theorem and the Adler zero. Furthermore, they satisfy on-shell recursion relations which together with the three-point scattering amplitude furnish a pure S-matrix formulation of incompressible fluid mechanics. Remarkably, the amplitudes of the non-Abelian Navier-Stokes equation also exhibit color-kinematics duality as an off-shell symmetry, for which the associated kinematic algebra is literally the algebra of spatial diffeomorphisms. Applying the double copy prescription, we then arrive at a new theory of a tensor bi-fluid. Finally, we present monopole solutions of the non-Abelian and tensor Navier-Stokes equations and observe a classical double copy structure.

    ↳ hep-thhep-ph40 citations
17. 17*

    Two-Scalar Bose-Einstein Condensates: From Stars to Galaxies

    Huai-Ke Guo🇺🇸 · Kuver Sinha🇺🇸 · Chen Sun🇮🇱 · Joshua Swaim🇺🇸 · Daniel Vagie🇺🇸

    We study the properties of Bose-Einstein Condensate (BEC) systems consisting of two scalars, focusing on both the case where the BEC is stellar scale as well as the case when it is galactic scale. After studying the stability of such systems and making contact with existing single scalar limits, we undertake a numerical study of the two interacting scalars using Einstein-Klein-Gordon (EKG) equations, including both non-gravitational self-interactions and interactions between the species. We show that the presence of extra scalars and possible interactions between them can leave unique imprints on the BEC system mass profile, especially when the system transitions from being dominated by one scalar to being dominated by the other. At stellar scales (nonlinear regime,) we observe that a repulsive interaction between the two scalars of the type $+{\varphi }_1^2{\varphi }_2^2$ can stabilize the BEC system and support it up to high compactness, a phenomenon only known to exist in the $+{\varphi }^4$ system. We provide simple analytic understanding of this behavior and point out that it can lead to interesting gravitational wave signals at LIGO-Virgo. At galactic scales, on the other hand, we show that two-scalar BECs can address the scaling problem that arises when one uses ultralight dark matter mass profiles to fit observed galactic core mass profiles. In the end, we construct a particle model of two ultralight scalars with the repulsive ${\varphi }_1^2{\varphi }_2^2$ interaction using collective symmetry breaking. We develop a fast numerical code that utilizes the relaxation method to solve the EKG system, which can be easily generalized to multiple scalars.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phJCAP(2021)·29 citations
18. 18*

    Coherent laser spectroscopy of highly charged ions using quantum logic

    P. Micke🇩🇪 · T. Leopold🇩🇪 · S. A. King🇩🇪 · E. Benkler🇩🇪 · L. J. Spieß🇩🇪 · L. Schmöger🇩🇪 · M. Schwarz🇩🇪 · J. R. Crespo López-Urrutia🇩🇪 · P. O. Schmidt🇩🇪

    Precision spectroscopy of atomic systems is an invaluable tool for the advancement of our understanding of fundamental interactions and symmetries. Recently, highly charged ions (HCI) have been proposed for sensitive tests of physics beyond the Standard Model and as candidates for high-accuracy atomic clocks. However, the implementation of these ideas has been hindered by the parts-per-million level spectroscopic accuracies achieved to date. Here, we cool a trapped HCI to the lowest reported temperatures, and introduce coherent laser spectroscopy on HCI with an eight orders of magnitude leap in precision. We probe the forbidden optical transition in ${}^{40}$Ar${}^{13+}$ at 441 nm using quantum-logic spectroscopy and measure both its excited-state lifetime and $g$-factor. Our work ultimately unlocks the potential of HCI, a large, ubiquitous atomic class, for quantum information processing, novel frequency standards, and highly sensitive tests of fundamental physics, such as searching for dark matter candidates or violations of fundamental symmetries.

    ↳ physics.atom-phhep-phphysics.ins-detphysics.plasm-ph+1Nature(2020)·106 citations
19. 19*

    Lorentz Invariance Violation Limits from the Spectral Lag Transition of GRB~190114C

    Shen-Shi Du🇨🇳 · Lin Lan🇨🇳 · Jun-Jie Wei🇨🇳 · Zi-Ming Zhou🇨🇳 · He Gao🇨🇳 · Lu-Yao Jiang🇨🇳 · Bin-Bin Zhang🇨🇳 · Zi-Ke Liu🇨🇳 · Xue-Feng Wu🇨🇳 · En-Wei Liang🇨🇳 · Zong-Hong Zhu🇨🇳

    The spectral lags of gamma-ray bursts (GRBs) have been viewed as the most promising probes of the possible violations of Lorentz invariance (LIV). However, these constraints usually depend on the assumption of the unknown intrinsic time lag in different energy bands and the use of a single highest-energy photon. A new approach to test the LIV effects has been proposed by directly fitting the spectral lag behavior of a GRB with a well-defined transition from positive lags to negative lags. This method simultaneously provides a reasonable formulation of the intrinsic time lag and robust lower limits on the quantum-gravity energy scales ($E_{\mathrm{QG}}$). In this work, we perform a global fitting to the spectral lag data of GRB~190114C by considering the possible LIV effects based on a Bayesian approach. We then derive limits on $E_{\mathrm{QG}}$ and the coefficients of the Standard Model Extension. The Bayes factors output in our analysis shows a very strong evidence for the spectral-lag transition in GRB~190114C. Our constraints on a variety of isotropic and anisotropic coefficients for LIV are somewhat weaker than existing bounds, but they can be viewed as comparatively robust and have the promise to complement existing LIV constraints. The observations of GRBs with higher-energy emissions and higher temporal resolutions will contribute to a better formulation of the intrinsic time lag and more rigorous LIV constraints in the dispersive photon sector.

    ↳ astro-ph.HEhep-phApJ(2021)·34 citations
20. 20*

    Exact WKB analysis of the vacuum pair production by time-dependent electric fields

    Hidetoshi Taya🇯🇵 · Toshiaki Fujimori🇯🇵 · Tatsuhiro Misumi🇯🇵 · Muneto Nitta🇯🇵 · Norisuke Sakai🇯🇵

    We study the vacuum pair production by a time-dependent strong electric field based on the exact WKB analysis. We identify the generic structure of a Stokes graph for systems with the vacuum pair production and show that the number of produced pairs is given by a product of connection matrices for Stokes segments connecting pairs of turning points. We derive an explicit formula for the number of produced pairs, assuming the semi-classical limit. The obtained formula can be understood as a generalization of the divergent asymptotic series method by Berry, and is consistent with other semi-classical methods such as the worldline instanton method and the steepest descent evaluation of the Bogoliubov coefficients done by Brezin and Izykson. We also use the formula to discuss effects of time-dependence of the applied strong electric field including the interplay between the perturbative multi-photon pair production and non-peturbative Schwinger mechanism, and the dynamically assisted Schwinger mechanism.

    ↳ hep-thhep-phmath-phmath.MP+1JHEP(2021)·64 citations
21. 21*

    A change of direction in pairwise neutrino conversion physics: The effect of collisions

    Shashank Shalgar🇩🇰 · Irene Tamborra🇩🇰

    Fast pairwise conversions of neutrinos may affect the flavor distribution in the core of neutrino-dense sources. We explore the interplay between collisions and fast conversions within a simplified framework that assumes angle-independent, direction-changing collisions in a neutrino gas that has no spatial inhomogeneity. Counter to expectations, we find that collisions may enhance fast flavor conversions instead of damping them. Our work highlights the need to take into account the feedback of collisions on the neutrino angular distributions self-consistently, in order to predict the flavor outcome in the context of fast pairwise conversions reliably.

    ↳ astro-ph.HEhep-phPRD(2021)·71 citations
22. 22*

    Hawking temperature and phonon emission in acoustic holes

    Massimo Mannarelli🇮🇹 · Dario Grasso🇮🇹 · Silvia Trabucco🇮🇹 · Maria Luisa Chiofalo🇮🇹

    Acoustic holes are the hydrodynamic analogue of standard black holes. Featuring an acoustic horizon, these systems spontaneously emit phonons at the Hawking temperature. We derive the Hawking temperature of the acoustic horizon by fully exploiting the analogy between black and acoustic holes within a covariant kinetic theory approach. After deriving the phonon distribution function from the covariant kinetic equations, we reproduce the expression of the Hawking temperature by equating the entropy and energy losses of the acoustic hole and the entropy and energy gains of the spontaneously emitted phonons. Differently from previous calculations we do not need a microscopical treatment of normal modes propagation. Our approach opens a different perspective on the meaning of Hawking temperature and its connection with entropy which may allow an easier study of non stationary horizons beyond thermodynamic equilibrium.

    ↳ gr-qccond-mat.otherhep-phPRD(2021)·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.