Thu·Feb 21, 2019Thursday·February 21, 2019

1. 01*

   Pseudoscalar Higgs boson pair production at a photon-photon collision in the two Higgs doublet model

   M. Demirci🇹🇷

   In this study, the direct pair production of the pseudoscalar Higgs boson at a photon-photon collision is analyzed in the context of two Higgs doublet model, taking account the complete one-loop contributions. In order to illustrate the effect of the new physics, four benchmark points scenarios, which are consistent with theoretical and current experimental constraints, are chosen in the type-I of THDM with an exact alignment limit. In these benchmark points, the CP even lightest Higgs boson ($h^0$) have the Standard Model like couplings to the gauge bosons. The effect of individual contributions from each type of one-loop diagrams on the total cross section are examined in detail. The dependence of total cross section on the center-of-mass energy is also presented at the various polarization configurations of the incoming photons. Moreover, the regions $m_{12}^2-\tan \beta$ and $m_A-\tan \beta$ in the parameter space of the THDM are scanned for some fixed values of other parameters. The box-type diagrams make a much larger contribution to the total cross section than the others at high energies. Total cross section can be enhanced by a two factor thanks to opposite polarized photons as well as threshold effects.

   hep-phTurk.J.Phys.(2019)·10 citations
2. 02*

   Simplest Radiative Dirac Neutrino Mass Models

   Shaikh Saad🇺🇸

   If neutrinos are Dirac particles, their right-handed partners must be present in the theory. Once introduced in the Standard Model (SM), the difference between the baryon number $B$ and the lepton number $L$ can be promoted to a local $U(1{)}_{B-L}$ symmetry since the corresponding gauge anomalies can be canceled by the right-handed neutrinos. Furthermore, the extremely small neutrino mass can be explained naturally if it is originated from the quantum correction. In this work, we propose simplest models of radiative Dirac neutrino mass using only $U(1{)}_{B-L}$ symmetry, and without introducing additional fermions and without imposing ad hoc symmetries. In this simple framework, we provide minimal models where Dirac neutrino mass appears at the (i) one-loop, (ii) two-loop and (iii) three-loop. By performing systematic analysis, we show that the minimal one-loop model requires three beyond SM scalar multiplets, whereas minimal two-loop and three-loop models require five. The presented two-loop and three-loop Dirac mass models have not appeared in the literature before.

   hep-phNPB(2019)·55 citations
3. 03*

   Conference Summary of QNP2018

   S. Kumano (KEK/J-PARC)🇯🇵

   This report is the summary of the Eighth International Conference on Quarks and Nuclear Physics (QNP2018). Hadron and nuclear physics is the field to investigate high-density quantum many-body systems bound by strong interactions. It is intended to clarify matter generation of universe and properties of quark-hadron many-body systems. The QNP is an international conference which covers a wide range of hadron and nuclear physics, including quark and gluon structure of hadrons, hadron spectroscopy, hadron interactions and nuclear structure, hot and cold dense matter, and experimental facilities. First, I introduce the current status of the hadron and nuclear physics field related to this conference. Next, the organization of the conference is explained, and a brief overview of major recent developments is discussed by selecting topics from discussions at the plenary sessions. They include rapidly-developing field of gravitational waves and nuclear physics, hadron interactions and nuclear structure with strangeness, lattice QCD, hadron spectroscopy, nucleon structure, heavy-ion physics, hadrons in nuclear medium, and experimental facilities of EIC, GSI-FAIR, JLab, J-PARC, Super-KEKB, and others. Nuclear physics is at a fortunate time to push various projects at these facilities. However, we should note that the projects need to be developed together with related studies in other fields such as gravitational physics, astrophysics, condensed-matter physics, particle physics, and fundamental quantum physics.

   hep-phhep-exnucl-exnucl-thJPS Conf.Proc.(2019)·0 citations
4. 04*

   Impact of form factor uncertainties on interpretations of coherent elastic neutrino-nucleus scattering data

   D. Aristizabal Sierra🇨🇱 · Jiajun Liao🇨🇳 · D. Marfatia🇺🇸

   The standard model coherent elastic neutrino-nucleus scattering (CE$\nu$NS) cross section is subject to nuclear form factor uncertainties, mainly driven by the root-mean-square radius of the neutron density distribution. Motivated by COHERENT phases I-III and future multi-ton direct detection dark matter searches, we evaluate these uncertainties in cesium iodide, germanium, xenon and argon detectors. We find that the uncertainties become relevant for momentum transfers $q\gtrsim 20$ MeV and are essentially independent of the form factor parameterization. Consequently, form factor uncertainties are not important for CE$\nu$NS induced by reactor or solar neutrinos. Taking into account these uncertainties, we then evaluate their impact on measurements of CE$\nu$NS at COHERENT, the diffuse supernova background (DSNB) neutrinos and sub-GeV atmospheric neutrinos. We also calculate the relative uncertainties in the number of COHERENT events for different nuclei as a function of recoil energy. For DSNB and atmospheric neutrinos, event rates at a liquid argon detector can be uncertain to more than 5%. Finally, we consider the impact of form factor uncertainties on searches for nonstandard neutrino interactions, sterile neutrinos and neutrino generalized interactions. We point out that studies of new physics using CE$\nu$NS data are affected by neutron form factor uncertainties, which if not properly taken into account may lead to the misidentification of new physics signals. The uncertainties quantified here are also relevant for dark matter direct detection searches.

   hep-phhep-exnucl-exnucl-thJHEP(2019)·104 citations
5. 05*

   Strong Decays of observed ${\Lambda }_c$ Baryons in the ${}^3{P}_0$ Model

   Jing-Jing Guo🇨🇳 · Pei Yang🇨🇳 · Ailin Zhang🇨🇳

   The strong decay widths and some important branching ratios of possible Okubo-Zweig-Iizuka(OZI)-allowed strong decay channels of ${\Lambda }_c(2595{)}^{+}$, ${\Lambda }_c(2625{)}^{+}$, ${\Lambda }_c(2765{)}^{+}$ (${\Sigma }_c(2765{)}^{+}$), ${\Lambda }_c(2860{)}^{+}$, ${\Lambda }_c(2880{)}^{+}$ and ${\Lambda }_c(2940{)}^{+}$ are computed in a ${}^3{P}_0$ model, and possible assignments of these ${\Lambda }_c$ are given. (1), ${\Lambda }_c(2595{)}^{+}$ and ${\Lambda }_c(2625{)}^{+}$ are possibly the $1P$-wave charmed baryons ${\Lambda }_{c1}({\frac{1}{2}}^{-})$ and ${\Lambda }_{c1}({\frac{3}{2}}^{-})$, respectively. (2), ${\Lambda }_c(2765{)}^{+}$ (${\Sigma }_c(2765{)}^{+}$) seems impossibly the $1P$-wave ${\Lambda }_c$, it could be the $2S$-wave or $1D$-wave charmed baryon. So far, the experimental information has not been sufficient for its identification. (3), ${\Lambda }_c(2860{)}^{+}$ seems impossibly $2S$-wave charmed baryon, it may be the $P$-wave ${\tilde{\Lambda }}_{c2}^{}({\frac{3}{2}}^{-})$ or ${\tilde{\Lambda }}_{c2}^{}({\frac{5}{2}}^{-})$, it could also be the $D$-wave ${\check{\Lambda }}_{c1}^2({\frac{1}{2}}^{+})$ or ${\check{\Lambda }}_{c1}^2({\frac{3}{2}}^{+})$. If the hypothesis that ${\Lambda }_c(2860{)}^{+}$ has $J^P={\frac{3}{2}}^{+}$ is true, ${\Lambda }_c(2860{)}^{+}$ is possibly the $D$-wave ${\check{\Lambda }}_{c1}^2({\frac{3}{2}}^{+})$ which has a predicted branching ratio $R=\Gamma ({\Sigma }_c(2520)\pi )/\Gamma ({\Sigma }_c(2455)\pi )=2.8$. (4), ${\Lambda }_c(2880{)}^{+}$ is impossibly a $1P$-wave or $2S$-wave charmed baryon, it may be a $D$-wave ${\check{\Lambda }}_{c3}^2({\frac{5}{2}}^{+})$ with ${\Gamma }_{total}=1.3$ MeV. The predicted branching ratio $R=\Gamma ({\Sigma }_c(2520)\pi )/\Gamma ({\Sigma }_c(2455)\pi )=0.35$, which is consistent with experiment. (5), ${\Lambda }_c(2940{)}^{+}$ is the $P$-wave ${\tilde{\Lambda }}_{c2}^{}({\frac{3}{2}}^{-})$ or ${\tilde{\Lambda }}_{c2}^{}({\frac{5}{2}}^{-})$, it is also possibly the $D$-wave ${\check{\Lambda }}_{c3}^2({\frac{5}{2}}^{+})$ or ${\check{\Lambda }}_{c3}^2({\frac{7}{2}}^{+})$.

   hep-phPRD(2019)·35 citations
6. 06*

   Anomaly-Induced Inhomogeneous Phase in Quark Matter without the Sign Problem

   Tomáš Brauner🇳🇴 · Georgios Filios🇳🇴 · Helena Kolešová🇳🇴

   We demonstrate the existence of an anomaly-induced inhomogeneous phase in a class of vector-like gauge theories without sign problem, thus disproving the long-standing conjecture that the absence of sign problem precludes spontaneous breaking of translational invariance. The presence of the phase in the two-color modification of quantum chromodynamics can be tested by an independent nonperturbative evaluation of the neutral pion decay constant as a function of external magnetic field. Our results provide a benchmark for future lattice studies of inhomogeneous phases in dense quark matter.

   hep-phhep-lathep-thPRL(2019)·33 citations
7. 07*

   More models for lepton mixing with four constraints

   D. Jurciukonis🇱🇹 · L. Lavoura🇵🇹

   We propose new lepton-mixing textures that may be enforced through well-defined symmetries in renormalizable models. Each of our textures has four sum rules for the neutrino mass observables. The models are based on the type-I seesaw mechanism; their charged-lepton mass matrices are diagonal because of the symmetries imposed. Each model has three versions, depending on the identification of the charged leptons. Testing all the models, we have found that five of them agree with the data at the 1 sigma level when the neutrino-mass ordering is normal, and two models agree with the data for an inverted ordering. We detail the predictions of each of those seven models.

   hep-phJHEP(2019)·1 citation
8. 08*

   Neutron Skin in CsI and Low-Energy Effective Weak Mixing Angle from COHERENT Data

   Xu-Run Huang🇨🇳 · Lie-Wen Chen🇨🇳

   Both the neutron skin thickness $\Delta R_{np}$ of atomic nuclei and the low-energy neutrino-nucleon ($\nu N$) interactions are of fundamental importance in nuclear and particle physics, astrophysics as well as new physics beyond the standard model (SM) but largely uncertain currently, and the coherent elastic neutrino-nucleus scattering (CE$\nu$NS) provides a clean way to extract their information. New physics beyond the SM may cause effectively a shift of the SM weak mixing angle ${\theta }_W$ in low-energy $\nu N$ interactions, leading to an effective weak mixing angle ${\theta }_W^{\ast }$. By analyzing the CE$\nu$NS data of the COHERENT experiment, we find that while a one-parameter fit to the COHERENT data by varying $\Delta R_{np}$ produces $\Delta R_{np}^{\mathrm{CsI}}\simeq 0.68_{-1.13}^{+0.91}$ fm for CsI with an unrealistically large central value by fixing ${\sin }^2{\theta }_W^{\ast }$ at the low-energy SM value of ${\sin }^2{\theta }_W^{\mathrm{SM}}=0.23857$, a two-dimensional fit by varying $\Delta R_{np}$ and ${\sin }^2{\theta }_W^{\ast }$ leads to a strong positive correlation between $\Delta R_{np}$ and ${\sin }^2{\theta }_W^{\ast }$ with significantly smaller central values of $\Delta R_{np}^{\mathrm{CsI}}\simeq 0.24_{-2.03}^{+2.30}$ fm and ${\sin }^2{\theta }_W^{\ast }=0.21_{-0.10}^{+0.13}$. Although the uncertainty is too large to claim a determination of $\Delta R_{np}^{\mathrm{CsI}}$ and ${\sin }^2{\theta }_W^{\ast }$, the present study suggests that the multi-dimensional fit is important in future analyses of high-precision CE$\nu$NS data. The implication of the possible deviation of ${\sin }^2{\theta }_W^{\ast }$ from ${\sin }^2{\theta }_W^{\mathrm{SM}}$ on new physics beyond the SM is also discussed.

   hep-phastro-ph.SRnucl-exnucl-thPRD(2019)·45 citations
9. 09*

   Constraining energy loss from high-$p_{\mathrm{T}}$ azimuthal asymmetries

   Carlota Andres🇺🇸 · Néstor Armesto🇪🇸 · Harri Niemi🇫🇮 · Risto Paatelainen🇫🇮 · Carlos A. Salgado🇪🇸

   The nuclear modification factor $R_{\mathrm{AA}}$ has been satisfactorily described by various jet quenching models. Nonetheless, all these formalisms, until very recently, underpredicted the high-$p_{\mathrm{T}}$ (> 10 GeV) elliptic flow $v_2$. We find that the simultaneous description of these observables requires to strongly suppress the quenching for the first $\sim 0.6$ fm after the collision. This shows the potential of jet quenching observables to constrain the dynamics of the initial stages of the evolution.

   hep-phnucl-thPoS(2019)·0 citations
10. 10*

    Probing Muonic Forces and Dark Matter at Kaon Factories

    Gordan Krnjaic🇺🇸 · Gustavo Marques-Tavares🇺🇸 · Diego Redigolo🇮🇱 · Kohsaku Tobioka🇺🇸

    Rare kaon decays are excellent probes of light, new weakly-coupled particles. If such particles $X$ couple preferentially to muons, they can be produced in $K\to \mu \nu X$ decays. In this letter we evaluate the future sensitivity for this process at NA62 assuming $X$ decays either invisibly or to di-muons. Our main physics target is the parameter space that resolves the $(g-2{)}_{\mu }$ anomaly, where $X$ is a gauged $L_{\mu }-L_{\tau }$ vector or a muon-philic scalar. The same parameter space can also accommodate dark matter freeze out or reduce the tension between cosmological and local measurements of $H_0$ if the new force decays to dark matter or neutrinos, respectively. We show that for invisible $X$ decays, a dedicated single muon trigger analysis at NA62 could probe much of the remaining $(g-2{)}_{\mu }$ favored parameter space. Alternatively, if $X$ decays to muons, NA62 can perform a di-muon resonance search in $K\to 3\mu \nu$ events and greatly improve existing coverage for this process. Independently of its sensitivity to new particles, we find that NA62 is also sensitive to the Standard Model predicted rate for $K\to 3\mu \nu$, which has never been measured.

    hep-phhep-exPRL(2020)·112 citations
11. 11*

    Higgs Parity, Strong CP, and Dark Matter

    David Dunsky🇺🇸 · Lawrence J. Hall🇺🇸 · Keisuke Harigaya🇺🇸

    An exact spacetime parity replicates the $SU(2)\times U(1)$ electroweak interaction, the Higgs boson $H$, and the matter of the Standard Model. This "Higgs Parity" and the mirror electroweak symmetry are spontaneously broken at scale $v^{\prime }=⟨H^{\prime }⟩\gg ⟨H⟩$, yielding the Standard Model below $v^{\prime }$ with a quartic coupling that essentially vanishes at $v^{\prime }$: ${\lambda }_{SM}(v^{\prime })\sim 10^{-3}$. The strong CP problem is solved as Higgs parity forces the masses of mirror quarks and ordinary quarks to have opposite phases. Dark matter is composed of mirror electrons, $e^{\prime }$, stabilized by unbroken mirror electromagnetism. These interact with Standard Model particles via kinetic mixing between the photon and the mirror photon, which arises at four-loop level and is a firm prediction of the theory. Physics below $v^{\prime }$, including the mass and interaction of $e^{\prime }$ dark matter, is described by $\text{one fewer parameter}$ than in the Standard Model. The allowed range of $m_{e^{\prime }}$ is determined by uncertainties in $({\alpha }_s,m_t,m_h)$, so that future precision measurements of these will be correlated with the direct detection rate of $e^{\prime }$ dark matter, which, together with the neutron electric dipole moment, will probe the entire parameter space.

    hep-phhep-exJHEP(2019)·57 citations
12. 12*

    Scanning Strategies at the Top Threshold at ILC

    Frank Simon🇩🇪

    A scan of the top quark pair production threshold at a future electron-positron collider provides the possibility for high-precision measurements of the top quark mass, and, when using two dimensional fits of the measured cross sections, also of other properties such as the width and the Yukawa coupling. The energy range of the scan and the distribution of the integrated luminosity can be optimized depending on the main goals of the threshold program. This contribution examines the possibility to determine the top quark mass in fast exploratory measurements with an adequate precision to enable such an optimization, and studies a scanning program with a reduced energy range of 6 GeV for the measurement of the mass, width and the Yukawa coupling, taking theoretical uncertainties from QCD scale variations and parametric uncertainties from the strong coupling constant into account.

    ↳ hep-exhep-ph12 citations
13. 13*

    Formation, Gravitational Clustering and Interactions of Non-relativistic Solitons in an Expanding Universe

    Mustafa A. Amin🇺🇸 · Philip Mocz🇺🇸

    We investigate the formation, gravitational clustering and interactions of solitons in a self-interacting, non-relativistic scalar field in an expanding universe. Rapid formation of large number of solitons is driven by attractive self-interactions of the field, whereas the slower clustering of solitons is driven by gravitational forces. Driven closer together by gravity, we see a rich plethora of dynamics in the soliton "gas" including mergers, scatterings and formation of soliton binaries. The numerical simulations are complemented by analytic calculations and estimates of (i) the relevant instability length and time scales, (ii) individual soliton profiles and their stability, (iii) number density of produced solitons, and (iv) the two point correlation function of soliton positions as evidence for gravitational clustering.

    ↳ astro-ph.COgr-qchep-phPRD(2019)·108 citations
14. 14*

    Nuclear states and spectra in holographic QCD

    Koji Hashimoto🇯🇵 · Yoshinori Matsuo🇹🇼 · Takeshi Morita🇯🇵

    A new method to study nuclear physics via holographic QCD is proposed. Multiple baryons in the Sakai-Sugimoto background are described by a matrix model which is a low energy effective theory of D-branes of the baryon vertices. We study the quantum mechanics of the matrix model and calculate the eigenstates of the Hamiltonian. The obtained states are found to coincide with known nuclear and baryonic states, and have appropriate statistics and charges. Calculated spectra of the baryon/nucleus for small baryon numbers show good agreement with experimental data. For hyperons, the Gell-Mann--Okubo formula is approximately derived. Baryon resonances up to spin $5/2$ and isospin $5/2$ and dibaryon spectra are obtained and compared with experimental data. The model partially explains even the magic numbers of light nuclei, $N=2,8$ and $20$.

    ↳ hep-thhep-phnucl-thJHEP(2019)·16 citations
15. 15*

    New Bounds on Dark Energy Induced Fifth Forces

    Philippe Brax🇫🇷 · Patrick Valageas🇫🇷 · Pierre Vanhove🇫🇷

    We consider the gravitational Wilsonian effective action at low energy when all the particles of the standard model have decoupled. When the ${\mathcal{R}}^2$ terms dominate, the theory is equivalent to a scalar-tensor theory with the universal coupling $\beta =1/\sqrt{6}$ to matter for which we present strong lower and upper bounds on the scalaron mass $m$ obtained by using results from the Eöt-Wash experiment on the modification of the inverse-square law, the observations of the hot gas of galaxy clusters and the Planck satellite data on the neutrino masses. In terms of the range of the scalar interaction mediated over a distance of order $m^{-1}$, this leads to the small interval $4\mu m\lesssim m^{-1}\lesssim 68\mu m$ within reach of future experimental tests of deviations from Newton's gravitational inverse-square law.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2019)·4 citations
16. 16*

    Benchmarking a Non-Equilibrium Approach to Photon Emission in Relativistic Heavy-Ion Collisions

    Anna Schäfer🇩🇪 · Juan M. Torres-Rincon🇺🇸 · Jonas Rothermel🇩🇪 · Niklas Ehlert🇩🇪 · Charles Gale🇨🇦 · Hannah Elfner🇩🇪

    In this work, the production of photons through binary scattering processes is investigated for equilibrated hadronic systems. More precisely, a non-equilibrium hadronic transport approach to describe relativistic heavy-ion collisions is benchmarked with respect to photon emission. Cross sections for photon production in $\pi +\rho \to \pi +\gamma$ and $\pi +\pi \to \rho +\gamma$ scattering processes are derived from an effective chiral field theory and implemented into the hadronic transport approach, SMASH (Simulating Many Accelerated Strongly-interacting Hadrons). The implementation is verified by systematically comparing the thermal photon rate to theoretical expectations. Further, the impact of form factors is discussed, scattering processes mediated by $\omega$ mesons are found to contribute significantly to the total photon production. Several comparisons of the yielded photon rates are performed: to parametrizations of the very same rates, as used in hydrodynamic simulations, to previous works relying on different cross sections for the production of direct photons from the hadronic stage, and to partonic rates. Finally, the impact of considering the finite width of the $\rho$ meson is investigated, where a significant enhancement of photon production in the low-energy region is observed. This benchmark is the first step towards a consistent treatment of photon emission in hybrid hydrodynamics+transport approaches and a genuine dynamical description.

    ↳ nucl-thhep-phnucl-exPRD(2019)·27 citations
17. 17*

    Comment to the CPT-symmetric Universe: Two possible extensions

    G.E. Volovik🇫🇮

    In Ref.1 (L. Boyle, K. Finn and N. Turok, CPT-Symmetric Universe, Phys. Rev. Lett. {\bf 121}, 251301 (2018)) the antispacetime Universe was suggested as the analytic continuation of our Universe across the Big Bang singularity in conformal time. We consider two different scenarios of analytic continuation. In one of them the analytic continuation is extended to the temperature of the system. This extension suggests that if such analytic continuation is valid, then it is possible that the initial stage of the evolution of the Universe on our side of the Big Bang was characterized by the negative temperature. In the second scenario, the analytic continuation is considered in the proper time. In this scenario the Big Bang represents the bifurcation point at which the $Z_2$ symmetry between the spacetime and antispacetime is spontaneously broken.

    ↳ gr-qccond-mat.otherhep-phJETP Lett.(2019)·10 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.