Wed·Sep 11, 2019Wednesday·September 11, 2019

1. 01*

   Vacuum stability of Froggatt-Nielsen models

   Felix Giese🇩🇪 · Thomas Konstandin🇩🇪

   We discuss vacuum stability in Froggatt-Nielsen (FN) models. One concern in FN models is that for large flavon VEVs the running of the quartic Higgs coupling is enhanced what might lead to a more severe instability compared to the Standard Model (SM). We study this issue using the renormalization-group improved scalar potential. Another issue is that the mixing between the Higgs and the flavon can potentially destabilize the potential. However, taking current bounds on the flavon phenomenology into account, we find that both effects do not lead to an instability that is more severe than in the SM.

   hep-phastro-ph.COJHEP(2019)·5 citations
2. 02*

   How To Discover Mirror Stars

   David Curtin🇨🇦 · Jack Setford🇨🇦

   Non-minimal hidden sectors are an important generic possibility and arise in highly motivated theories like Neutral Naturalness. A fraction of dark matter could therefore have hidden interactions analogous to Standard Matter (SM) electromagnetism and nuclear physics. This leads to the formation of \emph{Mirror Stars}: dark-sector analogues of regular stars that shine in dark photons. We examine the visible signatures of Mirror Stars in observations for the first time. If the dark and visible photon have a small kinetic mixing, SM matter is captured in Mirror Star cores, giving rise to an optical signal similar to but much fainter than white dwarfs, as well as a separate X-ray signal that represents a direct window into the Mirror Star core. This robust and highly distinctive signature is a smoking gun of Mirror Stars and could be discovered in optical and X-ray searches.

   hep-phastro-ph.HEastro-ph.SRPLB(2020)·58 citations
3. 03*

   Signatures of Mirror Stars

   David Curtin🇨🇦 · Jack Setford🇨🇦

   Motivated by theories of Neutral Naturalness, we argue that \emph{Mirror Stars} are a generic possibility in any hidden sector with analogues of Standard Model (SM) electromagnetism and nuclear physics. We show that if there exists a tiny kinetic mixing between the dark photon and the SM photon, Mirror Stars capture SM matter from the interstellar medium, which accumulates in the core of the Mirror Star and radiates in the visible spectrum. This signature is similar to, but in most cases much fainter than, ordinary white dwarfs. We also show for the first time that in the presence of captured SM matter, a fraction of dark photons from the core of the Mirror Star convert directly to SM photons, which leads to an X-ray signal that represents a direct probe of the properties of the Mirror Star core. These two signatures together are a highly distinctive, smoking gun signature of Mirror Stars. We show that Mirror Stars could be discovered in both optical and X-ray searches up to approximately 100-1000 light years away, for a range of well-motivated values of the kinetic mixing parameter.

   hep-phastro-ph.HEastro-ph.SRJHEP(2020)·68 citations
4. 04*

   Background evaluations for the chiral magnetic effect with normalized correlators using a multiphase transport model

   Subikash Choudhury🇨🇳 · Gang Wang🇺🇸 · Wanbing He🇨🇳 · Yu Hu🇨🇳 · Huan Zhong Huang🇺🇸

   The chiral magnetic effect (CME) induces an electric charge separation in a chiral medium along the magnetic field that is mostly produced by spectator protons in heavy-ion collisions. The experimental searches for the CME, based on the charge-dependent angular correlations ($\gamma$), however, have remained inconclusive, because the non-CME background contributions are not well understood. Experimentally, the $\gamma$ correlators have been measured with respect to the second-order (${\Psi }_2$) and the third-order (${\Psi }_3$) symmetry planes, defined as ${\gamma }_{112}$ and ${\gamma }_{123}$, respectively. The expectation was that with a proper normalization, ${\gamma }_{123}$ would provide a data-driven estimate for the background contributions in ${\gamma }_{112}$. In this work, we calculate different harmonics of the $\gamma$ correlators using a charge-conserving version of a multiphase transport (AMPT) model to examine the validity of the said assumption. We find that the pure-background AMPT simulations do not yield an equality in the normalized ${\gamma }_{112}$ and ${\gamma }_{123}$, quantified by ${\kappa }_{112}$ and ${\kappa }_{123}$, respectively. Furthermore, we test another correlator, ${\gamma }_{132}$, within AMPT, and discuss the relation between different $\gamma$ correlators.

   hep-phhep-exnucl-exEPJC(2020)·16 citations
5. 05*

   Dispersive analysis of the ${\gamma }^{\ast }{\gamma }^{\ast }\to \pi \pi$ process

   Igor Danilkin🇩🇪 · Oleksandra Deineka🇩🇪 · Marc Vanderhaeghen🇩🇪

   In this paper, we present a dispersive analysis of the double-virtual photon-photon scattering to two pions up to 1.5 GeV. Through unitarity, this process is very sensitive to hadronic final state interaction. For the $s$-wave, we use a coupled-channel $\pi \pi ,K\bar{K}$ analysis which allows a simultaneous description of both $f_0(500)$ and $f_0(980)$ resonances. For higher energies, $f_2(1270)$ shows up as a dominant structure which we approximate by a single channel $\pi \pi$ rescattering in the $d$-wave. In the dispersive approach, the latter requires taking into account $t$- and $u$-channel vector-meson exchange left-hand cuts which exhibit an anomalous-like behavior for large space-like virtualities. In our paper, we show how to readily incorporate such behavior using a contour deformation. Besides, we devote special attention to kinematic constraints of helicity amplitudes and show their correlations explicitly.

   hep-phPRD(2020)·65 citations
6. 06*

   Visible Sterile Neutrinos as the Earliest Relic Probes of Cosmology

   Graciela B. Gelmini🇺🇸 · Philip Lu🇺🇸 · Volodymyr Takhistov🇺🇸

   A laboratory detection of a sterile neutrino could provide the first indication of the evolution of the Universe before Big-Bang Nucleosynthesis (BBN), an epoch yet untested. Such "visible" sterile neutrinos are observable in upcoming experiments such as KATRIN/TRISTAN and HUNTER in the keV mass range and PTOLEMY and others in the eV mass range. A set of standard assumptions is typically made about cosmology before the temperature of the Universe was 5 MeV. However, non-standard pre-BBN cosmologies based on alternative assumptions could arise in motivated theoretical models and are equally in agreement with all existing data. We revisit the production of sterile neutrinos of mass 0.01 eV to 1 MeV in two examples of such models: scalar-tensor and low reheating temperature pre-BBN cosmologies. In both of them, the putative 3.5 keV X-ray signal line corresponds to a sterile neutrino with a mixing large enough to be tested in upcoming laboratory experiments. Additionally, the cosmological/astrophysical upper limits on active-sterile neutrino mixings are significantly weaker than in the standard pre-BBN cosmology, which shows that these limits are not robust. For example, in the scalar-tensor case the potential signal regions implied by the LSND and MiniBooNE short-baseline as well as the DANSS and NEOS reactor experiments are entirely not bound by cosmological restrictions. Our work highlights that sterile neutrinos may constitute a sensitive probe of the pre-BBN epoch.

   hep-phastro-ph.COhep-exPLB(2020)·35 citations
7. 07*

   Comments on "Three regimes of QCD" by L.Glozman

   Edward Shuryak🇺🇸

   There are no "three regimes of QCD", as speculated in that paper. There are only two, separated by already well known $T_c\sim 155MeV$. Above it electric interactions are screened rather then confined. Magnetic ones remain confined all the way to $T\to \infty$. Spectrum of "mesonic screening masses" is there, but they do not represent real masses. At high $T$ they correspond to "heavy quarkonia" of 2+1 d gauge theory, which is well known to be a confining theory. There is no reason to expect any transition unbinding them, at $T\sim 1GeV$ as claimed. I make calculation of correction to screening masses in 2+1d at high temperature including spatial screening tension and find results in agreement with recent lattice data.

   hep-ph4 citations
8. 08*

   Lessons from $T_{\mu }^{\mu }$ on inflation models: two-scalar theory and Yukawa theory

   Ayuki Kamada🇰🇷 · Takumi Kuwahara🇰🇷

   We demonstrate two properties of the trace of the energy-momentum tensor $T_{\mu }^{\mu }$ in the flat spacetime. One is the decoupling of heavy degrees of freedom; i.e., heavy degrees of freedom leave no effect for low-energy $T_{\mu }^{\mu }$-inserted amplitudes. This is intuitively apparent from the effective field theory point of view, but one has to take into account the so-called trace anomaly to explicitly demonstrate the decoupling. As a result, for example, in the $R^2$ inflation model, scalaron decay is insensitive to heavy degrees of freedom when a matter sector $minimally$ couples to gravity (up to a non-minimal coupling of a matter scalar field other than the scalaron). The other property is a quantum contribution to a non-minimal coupling of a scalar field. The non-minimal coupling disappears from the action in the flat spacetime, but leaves the so-called improvement term in $T_{\mu }^{\mu }$. We study the renormalization group equation of the non-minimal coupling to discuss its quantum-induced value and implications for inflation dynamics. We work it out in the two-scalar theory and Yukawa theory.

   hep-phgr-qcPRD(2020)·6 citations
9. 09*

   Lessons from $T_{\mu }^{\mu }$ on inflation models: two-loop renormalization of $\eta$ in the scalar QED

   Ayuki Kamada🇰🇷 · Takumi Kuwahara🇰🇷

   A non-minimal coupling $\eta$ has been attracting growing interest particularly in the context of inflation models, though its quantum nature is not clear yet. We study the renormalization of a non-minimal coupling in the scalar quantum electrodynamics (QED). We find $no$ inhomogeneous term of the renormalization group equation (RGE) at the two-loop level. This is similar to other theories, where an inhomogeneous term of the RGE appears only at a higher-loop order: e.g., four-loop order in $\lambda {\varphi }^4$ theory.

   hep-phgr-qcPRD(2021)·6 citations
10. 10*

    Solving the strong CP problem with horizontal gauge symmetry

    Gongjun Choi🇨🇳 · Tsutomu T. Yanagida🇯🇵

    We present a solution to the strong CP problem, which relies on the horizontal gauge symmetry and CP invariance in a full theory. Similar to other Nelson-Barr type solutions, CP violation in both the strong and weak sectors in the Standard model (SM) is attributed to the condensation of complex scalars $\Phi$ in the model. The model is differentiated by others in that it explains the hierarchy in quark-Higgs Yukawa coupling in the SM based on a series of sequential breaking of the horizontal $SU(3{)}_f$ gauge symmetry. The experimental constraint $\overline{\theta }\lesssim 10^{-10}$ requires $<\Phi >\lesssim 10^{13}-10^{14}\mathrm{GeV}$ (vacuum expectation value of complex scalars) and $\lambda \lesssim 10^{-6}$ (scalar quartic coupling). We show that this small coupling is natural in the sense of 'tHooft naturalness. Compared to other models of Nelson-Barr type with CP breaking scale ${\Lambda }_{CP}\lesssim 10^8\mathrm{GeV}$, our model is more advantageous in terms of consistency with the thermal leptogenesis.

    hep-phhep-thPRD(2019)·12 citations
11. 11*

    Anomalies in the production of multiple leptons at the LHC

    Stefan von Buddenbrock🇿🇦 · Bruce Mellado🇿🇦

    Based on a number of features from proton-proton collisions taken during Run 1 data taking period at the LHC, a boson with a mass around the Electro-Weak scale was postulated such that a significant fraction of its decays would comprise the Standard Model (SM) Higgs boson and an additional scalar, $S$. One of the phenomenological implications of a simplified model, where $S$ is treated a SM Higgs boson, is the anomalous production of high transverse momentum leptons. A combined study of Run 1 and Run 2 data is indicative of very significant discrepancies between the data and SM Monte Carlos in a variety of final states involving multiple leptons with and without $b$-quarks. These discrepancies appear in corners of the phase-space where different SM processes dominate, indicating that the potential mismodeling of a particular SM process is unlikely to explain them. Systematic uncertainties from the prediction of SM processes evaluated with currently available tools seem unable to explain away these discrepancies. The internal consistency of these anomalies and their interpretation in the framework of the original hypothesis is quantified.

    hep-phhep-ex3 citations
12. 12*

    Vertex renormalization and hard scattering symmetry breaking corrections to $B$ to axial vector meson form factors at large recoil

    Arslan Sikandar🇵🇰 · M. Jamil Aslam🇵🇰 · Ishtiaq Ahmed🇵🇰 · Saba Shafaq🇵🇰

    The symmetries arise due to heavy quark and large energy limit help us to reduce the number of independent form factors in the heavy-to-light $B$-meson decays. It is expected that these symmetry relations are not exact and are broken by the perturbative effects, namely, the vertex corrections and the hard-spectator scatterings. The former are included in the form factors via vertex renormalization whereas the later are calculated through light-cone distribution amplitudes. We first calculate these symmetry breaking corrections to the form factors involved in semileptonic $B$-meson to an axial-vector $(K_1)$-meson decay. Later, by using these form factors we see their effect on the physical observables such as the zero-position of the forward-backward $({\mathcal{A}}_{FB})$ asymmetry and the longitudinal lepton polarization ($P_L$) asymmetry in $B\to K_1(1270){\mu }^{+}{\mu }^{-}$ decay. We find that as a result of these corrections to the form factors, the zero-position of the forward-backward asymmetry is shifted by $10\%$ from its SM value while the effects on $P_L$ are rather insignificant.

    hep-phhep-exPRD(2019)·7 citations
13. 13*

    Traces of the nuclear liquid-gas phase transition in the analytic properties of hot QCD

    Oleh Savchuk🇺🇦 · Volodymyr Vovchenko🇩🇪 · Roman V. Poberezhnyuk🇺🇦 · Mark I. Gorenstein🇺🇦 · Horst Stoecker🇩🇪

    The nuclear liquid-gas transition at normal nuclear densities, $n\sim n_0=0.16$ fm${}^{-3}$, and small temperatures, $T\sim 20$ MeV, has a large influence on analytic properties of the QCD grand-canonical thermodynamic potential. A classical van der Waals equation is used to determine these unexpected features due to dense cold matter qualitatively. The existence of the nuclear matter critical point results in thermodynamic branch points, which are located at complex chemical potential values, for $T>T_c\simeq 20$ MeV, and exhibit a moderate model dependence up to rather large temperatures $T\lesssim 100$ MeV. The behavior at higher temperatures is studied using the van der Waals hadron resonance gas (vdW-HRG) model. The baryon-baryon interactions have a decisive influence on the QCD thermodynamics close to ${\mu }_B=0$. In particular, nuclear matter singularities limit the radius of convergence $r_{{\mu }_B/T}$ of the Taylor expansion in ${\mu }_B/T$, with $r_{{\mu }_B/T}\sim 2-3$ values at $T\sim 140-170$ MeV obtained in the vdW-HRG model.

    hep-phhep-latnucl-thPRC(2020)·25 citations
14. 14*

    The Shear Viscosity to Entropy Density Ratio of Hagedorn States

    Jan Rais🇩🇪 · Kai Gallmeister🇩🇪 · Carsten Greiner🇩🇪

    The fireball concept of Rolf Hagedorn, developed in the 1960's, is an alternative description of hadronic matter. Using a recently derived mass spectrum, we use the transport model GiBUU to calculate the shear viscosity of a gas of such Hagedorn states, applying the Green-Kubo method to Monte-Carlo calculations. Since the entropy density is rising ad infinitum near $T_H$, this leads to a very low shear viscosity to entropy density ratio near $T_H$. Further, by comparing our results with analytic expressions, we find a nice extrapolation behavior, indicating that a gas of Hagedorn states comes close or even below the boundary $1/4\pi$ from AdS-CFT.

    hep-phnucl-thPRD(2020)·17 citations
15. 15*

    Probing Flavor Non-Universal Theories Through Higgs Physics at the LHC and Future Colliders

    Wen Han Chiu🇺🇸 · Zhen Liu🇺🇸 · Lian-Tao Wang🇺🇸

    We explored the possibility that Higgs coupling to new physics violates flavor universality. In particular, we parameterize such models with dimension-six effective operators which modify the coupling between the first generation quarks, Higgs boson, and $Z$ boson. Through the use of boosted Higgsstrahlung events at both the HL-LHC and potential future hadron colliders, as well as existing ATLAS data for background estimates, we projected constraints on the scale of new physics as a function of the Wilson coefficient. The high energy $Zh$ process will provide unique information about these class of operators, and the sensitivity is competitive with the LEP electroweak precision measurements. We include different scenarios of the overall systematic uncertainties and the PDF uncertainties when presenting the projected sensitivities. We also discuss the constraints from FCNCs to these flavor-violating models and the complementarity of the exotic Higgs decay to the $Zh$ process.

    hep-phPRD(2020)·7 citations
16. 16*

    Wino potential and Sommerfeld effect at NLO

    Martin Beneke🇩🇪 · Robert Szafron🇩🇪 · Kai Urban (TUM)🇩🇪

    We calculate the SU(2)$\times$U(1) electroweak static potential between a fermionic triplet in the broken phase of the Standard Model in the one-loop order (NLO). The one-loop correction provides the leading non-relativistic correction to the large Sommerfeld effect in the annihilation of wino or wino-like dark matter particles ${\chi }^0$. We find sizeable modifications of the ${\chi }^0{\chi }^0$ annihilation cross section and determine the shifts of the resonance locations due to the loop correction to the wino potential.

    hep-phastro-ph.HEPLB(2020)·35 citations
17. 17*

    Probing effects of new physics in ${\Lambda }_b^0\to {\Lambda }_c^{+}{\mu }^{-}{\bar{\nu }}_{\mu }$ decays

    Martina Ferrillo🇨🇭 · Abhijit Mathad🇨🇭 · Patrick Owen🇨🇭 · Nicola Serra🇨🇭

    We present, for the first time, the six-fold differential decay density expression for ${\Lambda }_b^0\to {\Lambda }_c^{+}{l}^{-}{\bar{\nu }}_l$, taking into account the polarisation of the ${\Lambda }_b^0$ baryon and a complete basis of new physics operators. Using the expected yield in the current dataset collected at the LHCb experiment, we present sensitivity studies to determine the experimental precision on the Wilson coefficients of the new physics operators with ${\Lambda }_b^0\to {\Lambda }_c^{+}{\mu }^{-}{\bar{\nu }}_{\mu }$ decays in two scenarios. In the first case, unpolarised ${\Lambda }_b^0\to {\Lambda }_c^{+}{\mu }^{-}{\bar{\nu }}_{\mu }$ decays with ${\Lambda }_c^{+}\to p{K}^{+}{\pi }^{-}$ are considered, whereas polarised ${\Lambda }_b^0\to {\Lambda }_c^{+}{\mu }^{-}{\bar{\nu }}_{\mu }$ decays with ${\Lambda }_c^{+}\to p{K}_S^0$ are studied in the second. For the latter scenario, the experimental precision that can be achieved on the determination of ${\Lambda }_b^0$ polarisation and ${\Lambda }_c^{+}$ weak decay asymmetry parameter is also presented.

    hep-phhep-exJHEP(2019)·25 citations
18. 18*

    Universality driven analytic structure of the QCD crossover: radius of convergence in the baryon chemical potential

    Swagato Mukherjee🇺🇸 · Vladimir Skokov🇺🇸

    Recent lattice QCD calculations strongly indicate that the chiral crossover of QCD at zero baryon chemical potential \mu_B is a remnant of the second-order chiral phase transition. Universal properties of this second-order phase transition can be mapped to QCD temperature T and \mu_B using non-universal parameters determined by lattice QCD recently. Motivated by these results, first, we discuss the analytic structure of the partition function in the QCD crossover regime - the so-called Yang-Lee edge singularity - solely based on universal properties. Next, utilizing the lattice QCD results for non-universal parameters we map this singularity to the real T and complex \mu_B plane, leading to the determination of the radius of convergence is in \mu_B in the QCD crossover regime. These universality- and QCD-based results provide tight constraints on the range of validity of the lattice QCD calculations at \mu_B. Implication of this result on the location of the conjectured QCD critical point is discussed.

    hep-phhep-latnucl-thPRD(2021)·55 citations
19. 19*

    The prospect of charm quark magnetic moment determination

    A.S. Fomin🇫🇷 · S. Barsuk🇫🇷 · A.Yu. Korchin🇺🇦 · V.A. Kovalchuk🇺🇦 · E. Kou🇫🇷 · M. Liul🇫🇷 · A. Natochii🇫🇷 · E. Niel🇫🇷 · P. Robbe🇫🇷 · A. Stocchi🇫🇷

    In this paper, we discuss the theoretical framework and the experimental measurements of the magnetic moment of the charm baryons. The ${\Lambda }_c^{+}$ magnetic moment is particularly interesting since it is equal to the magnetic moment of the charm quark. The measurements of the magnetic moments of other charm baryons, such as ${\Xi }_c$, allow to perform detailed spectroscopy studies. The magnetic moment of the ${\Lambda }_c$ can be determined using radiative charmonium decay and the present results show a tension with majority of theoretical predictions. As recently pointed out, the magnetic moment of the charm baryons can be directly measured using bent-crystal experiments at LHC. The possibility of precisely measure the magnetic moments of charm baryons needs precise measurement of their polarisation and weak decay parameters. In this paper, we revisit the formalism of the angular analysis needed for these measurements and make a detailed evaluation of initial polarisation of deflected ${\Lambda }_c$ baryons as a function of crystal orientation. We found a special orientation of the crystal that gives the opportunity to measure the ${\Lambda }_c$ dimensionless electric dipole moment almost with the same precision as its $g$-factor, which is more than an order of magnitude more efficient than suggested before. In conclusion, we stress the importance to perform precise measurements of initial polarisation and weak decay parameters of ${\Lambda }_c$ baryon to effectively compare the direct and from decay measurements of magnetic moments.

    hep-phhep-exEPJC(2020)·28 citations
20. 20*

    Higgs phenomenology as a probe of sterile neutrinos

    Jonathan M. Butterworth🇬🇧 · Mikael Chala🇬🇧 · Christoph Englert🇬🇧 · Michael Spannowsky🇬🇧 · Arsenii Titov🇬🇧

    Physics beyond the Standard Model can manifest itself as both new light states and heavy degrees of freedom. In this paper, we assume that the former comprise only a sterile neutrino, $N$. Therefore, the most agnostic description of the new physics is given by an effective field theory built upon the Standard Model fields as well as $N$. We show that Higgs phenomenology provides a sensitive and potentially crucial tool to constrain effective gauge interactions of sterile neutrinos, not yet probed by current experiments. In parallel, this motivates a range of new Higgs decay channels with clean signatures as candidates for the next LHC runs, including $h\to \gamma +p_T^{\text{miss}}$ and $h\to \gamma \gamma +p_T^{\text{miss}}$.

    hep-phhep-exPRD(2019)·56 citations
21. 21*

    Leak-in Dark Matter

    Jared A. Evans🇺🇸 · Cristian Gaidau🇺🇸 · Jessie Shelton🇺🇸

    We introduce leak-in dark matter, a novel out-of-equilibrium origin for the dark matter (DM) in the universe. We provide a comprehensive and unified discussion of a minimal, internally-thermalized, hidden sector populated from an out-of-equilibrium, feeble connection to the hotter standard model (SM) sector. We emphasize that when this out-of-equilibrium interaction is renormalizable, the colder sector undergoes an extended phase of non-adiabatic evolution largely independent of initial conditions, which we dub "leak-in." We discuss the leak-in phase in generality, and establish the general properties of dark matter that freezes out from a radiation bath undergoing such a leak-in phase. As a concrete example, we consider a model where the SM has an out-of-equilibrium B-L vector portal interaction with a minimal hidden sector. We discuss the interplay between leak-in and freezein processes in this theory in detail and demonstrate regions where leak-in yields the full relic abundance. We study observational prospects for B-L vector portal leak-in DM, and find that despite the requisite small coupling to the SM, a variety of experiments can serve as sensitive probes of leak-in dark matter. Additionally, regions allowed by all current constraints yield DM with self-interactions large enough to address small-scale structure anomalies.

    hep-phJHEP(2020)·31 citations
22. 22*

    Light neutrino masses from gravitational condensation: the Schwinger-Dyson approach

    Gabriela Barenboim🇪🇸 · Jessica Turner🇺🇸 · Ye-Ling Zhou🇬🇧

    In this work we demonstrate that non-zero neutrino masses can be generated from gravitational interactions. We solve the Schwinger-Dyson equations to find a non-trivial vacuum thereby determining the scale of the neutrino condensate and the number of new particle degrees of freedom required for gravitationally induced dynamical chiral symmetry breaking. We show for minimal beyond the Standard Model particle content, the scale of the condensation occurs close to the Planck scale.

    hep-phhep-thEPJC(2021)·10 citations
23. 23*

    Supernarrow Dibaryons

    L.V. Fil'kov🇷🇺

    An analysis of the experimental search for supernarrow dibaryons (SNDs) have been performed. The sum rules for SND masses have been constructed. The calculated values of the SND masses are in good agreement with the existing experimental values. It has been shown that the SND decay leads to the formation of N* with small masses. Experimental observations of N* is an additional confirmation of the possibility of the SND existence.

    hep-phnucl-thPhys.Part.Nucl.(2019)·0 citations
24. 24*

    Anapole Dark Matter Quantum Mechanics

    J. Gamboa🇨🇱 · F. Mendez🇨🇱 · N. Tapia🇨🇱

    The dynamics of an anapole seen as dark matter at low energies is studied by solving the Schrödinger-Pauli equation in a potential involving Dirac-delta and its derivatives in three-dimensions. This is an interesting mathematical problem that, as far as we know, has not been previously discussed. We show how bound states emerge in this approach and the scattering problem is formulated (and solved) directly. The total cross section is in full agreement with independent calculations in the standard model.

    ↳ hep-thhep-phPRD(2020)·2 citations
25. 25*

    From 3d dualities to hadron physics

    Naoto Kan🇯🇵 · Ryuichiro Kitano🇯🇵 · Shimon Yankielowicz🇮🇱 · Ryo Yokokura🇯🇵

    When one of the space-time dimension is compactified on $S^1$, the QCD exhibits the chiral phase transition at some critical radius. When we further turn on a background $\theta$ term which depends on the $S^1$ compactified coordinate, a topological ordered phase appears at low energy via the winding of $\theta$. We discuss what kind of theories can describe the physics near the critical point by requiring the matching of topological field theories in the infrared. As one of the possibilities, we propose a scenario where the $\rho$ and $\omega$ mesons form a $U(N_f)$ gauge theory near the critical point. In the phase where the chiral symmetry is restored, they become the dual gauge boson of the gluon related by the level-rank duality between the three dimensional gauge theories, $SU(N{)}_{N_f}$ and $U(N_f{)}_{-N}$.

    ↳ hep-thhep-phPRD(2020)·29 citations
26. 26*

    Virtual Delbrück scattering and the Lamb shift in light hydrogen-like atoms

    Robert Szafron🇩🇪 · Evgeny Yu. Korzinin🇷🇺 · Valery A. Shelyuto🇷🇺 · Vladimir G. Ivanov🇷🇺 · Savely G. Karshenboim🇩🇪

    We return to the problem of evaluation of the light-by-light contribution to the energy levels of the hydrogen atom. We find an additional contribution directly related to the Delbrück scattering amplitude. The new correction is larger than the previously included light-by-light terms at order~${\alpha }^2(Z\alpha {)}^6\ln (Z\alpha )m_e$. We consider the effective potential in position space using an effective field theory approach and evaluate light-by-light corrections to the energy levels of states with non-zero orbital momentum as well as to the weighted difference of $s$ states. We also determine the large distance asymptotic behaviour of the effective potential induced by the light-by-light scattering in muonic atoms.

    ↳ physics.atom-phhep-phPRA(2019)·13 citations
27. 27*

    Are gravitating magnetic monopoles stable?

    Ben Kain🇺🇸

    The gravitating Julia-Zee dyon is a particle-like solution with both electric and magnetic charge. It is found in the Einstein-Yang-Mills-Higgs system of SU(2) with a scalar field in the adjoint representation coupled to gravity. Within the magnetic ansatz this system is reduced from describing dyons to describing the gravitating 't Hooft-Polyakov magnetic monopole. The stability of the well-known static gravitating magnetic monopole solutions with respect to perturbations within the magnetic ansatz--so-called magnetic perturbations--is well studied, but their stability with respect to perturbations outside the magnetic ansatz--so-called sphaleronic perturbations--is not. I undertake a purely numerical study by adding sphaleronic perturbations to gravitating magnetic monopole solutions and then dynamically evolving the system. For large perturbations I find that the system heads toward a dyon configuration, as expected. For sufficiently small perturbations, however, the system oscillates about the magnetic ansatz in a manner consistent with oscillations about a stable equilibrium.

    ↳ gr-qchep-phhep-thPRD(2019)·2 citations
28. 28*

    Pure spin-3/2 representation with consistent interactions

    T. Mart🇮🇩 · J. Kristiano🇮🇩 · S. Clymton🇮🇩

    We have investigated the use of pure spin-3/2 propagator with consistent interaction Lagrangians to describe the property of spin-3/2 resonance. For this purpose we use the antisymmetric tensor spinor representation. By using the primary and secondary constraints we obtain the interaction fields that have the correct degrees of freedom. To visualize the result we calculate the contribution of spin-3/2 $\Delta$ resonance to the total cross section of pion scattering and pion photoproduction off the nucleon. The result confirms that the scattering and photoproduction amplitudes obtained from the pure spin-3/2 representation with consistent interaction Lagrangians exhibit the required property of a resonance. Therefore, the formalism can be used for phenomenological investigations in the realm of nuclear and particle physics.

    ↳ nucl-thhep-phPRC(2019)·13 citations
29. 29*

    Cosmic Birefringence Test of the Hubble Tension

    Ludovico M. Capparelli🇮🇹 · Robert R. Caldwell🇺🇸 · Alessandro Melchiorri🇮🇹

    An early dark energy component consisting of a cosmic pseudo Nambu-Goldstone boson has been recently proposed to resolve the Hubble tension -- the four-sigma discrepancy between precision measurements of the expansion rate of the universe. Here we point out that such an axion-like component may be expected to couple to electromagnetism by a Chern-Simons term, and will thereby induce an anisotropic cosmic birefringence signal in the polarization of the cosmic microwave background (CMB). We show that observations of the rotation-angle power spectrum and cross-correlation with CMB temperature anisotropy can confirm the presence of this early dark energy component. Future CMB data as expected from the CMB-S4 experiment will improve sensitivity to this effect by two orders of magnitude and help in discriminating between different Hubble tension scenarios.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2020)·53 citations
30. 30*

    One-loop renormalization in Galileon effective field theory

    Lavinia Heisenberg🇨🇭 · Christian F. Steinwachs🇩🇪

    We investigate the renormalization structure of scalar Galileons in flat spacetime. We explicitly calculate the ultraviolet divergent one-loop contributions to the 2-point, 3-point, 4-point, and 5-point functions. We discuss the structure of the counterterms and their hierarchy within an effective field theory expansion. We comment on different resummation schemes, including a geometric resummation for which our results could be generalized to arbitrary n-point functions.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2020)·18 citations
31. 31*

    Dark Shards: velocity substructure from Gaia and direct searches for dark matter

    Ciaran A. J. O'Hare🇦🇺 · N. Wyn Evans🇬🇧 · Christopher McCabe🇬🇧 · GyuChul Myeong🇬🇧 · Vasily Belokurov🇬🇧

    Data from the Gaia satellite show that the solar neighbourhood of the Milky Way's stellar halo is imprinted with substructure from several accretion events. Evidence of these events is found in "the Shards", stars clustering with high significance in both action space and metallicity. Stars in the Shards share a common origin, likely as ancient satellite galaxies of the Milky Way, so will be embedded in dark matter (DM) counterparts. These "Dark Shards" contain two substantial streams (S1 and S2), as well as several retrograde, prograde and lower energy substructures. The retrograde stream S1 has a very high Earth-frame speed of $\sim 550$ km s${}^{-1}$ while S2 moves on a prograde, but highly polar orbit and enhances the peak of the speed distribution at around $300$ km s${}^{-1}$. The presence of the Dark Shards locally leads to modifications of many to the fundamental properties of experimental DM signals. The~S2 stream in particular gives rise to an array of effects in searches for axions and in the time dependence of nuclear recoils: shifting the peak day, inducing nonsinusoidal distortions, and increasing the importance of the gravitational focusing of DM by the Sun. Dark Shards additionally bring new features for directional signals, while also enhancing the DM flux towards Cygnus.

    ↳ astro-ph.GAhep-phPRD(2020)·87 citations
32. 32*

    Directionally Accelerated Detection of an Unknown Second Reactor with Antineutrinos for Mid-Field Nonproliferation Monitoring

    D. L. Danielson (1, 2, 3)🇺🇸 · O. A. Akindele (1)🇺🇸 · M. Askins (4, 5, 2)🇺🇸 · M. Bergevin (1)🇺🇸 · A. Bernstein (1)🇺🇸 · J. Burns (6)🇬🇧 · A. Carroll (7)🇬🇧 · J. Coleman (7)🇬🇧 · R. Collins (7)🇬🇧 · C. Connor (8)🇺🇸 · D. F. Cowen (9, 10)🇺🇸 · F. Dalnoki-Veress (11)🇺🇸 and 58 other authors

    When monitoring a reactor site for nuclear nonproliferation purposes, the presence of an unknown or hidden nuclear reactor could be obscured by the activities of a known reactor of much greater power nearby. Thus when monitoring reactor activities by the observation of antineutrino emissions, one must discriminate known background reactor fluxes from possible unknown reactor signals under investigation. To quantify this discrimination, we find the confidence to reject the (null) hypothesis of a single proximal reactor, by exploiting directional antineutrino signals in the presence of a second, unknown reactor. In particular, we simulate the inverse beta decay (IBD) response of a detector filled with a 1 kT fiducial mass of Gadolinium-doped liquid scintillator in mineral oil. We base the detector geometry on that of WATCHMAN, an upcoming antineutrino monitoring experiment soon to be deployed at the Boulby mine in the United Kingdom whose design and deployment will be detailed in a forthcoming white paper. From this simulation, we construct an analytical model of the IBD event distribution for the case of one $4\mathrm{GWt}\pm 2\%$ reactor 25 km away from the detector site, and for an additional, unknown, 35 MWt reactor 3 to 5 km away. The effects of natural-background rejection cuts are approximated. Applying the model, we predict $3\sigma$ confidence to detect the presence of an unknown reactor within five weeks, at standoffs of 3 km or nearer. For more distant unknown reactors, the $3\sigma$ detection time increases significantly. However, the relative significance of directional sensitivity also increases, providing up to an eight week speedup to detect an unknown reactor at 5 km away. Therefore, directionally sensitive antineutrino monitoring can accelerate the mid-field detection of unknown reactors whose operation might otherwise be masked by more powerful reactors in the vicinity.

    ↳ physics.ins-dethep-exhep-phphysics.app-ph3 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.