Wed·May 2, 2018Wednesday·May 2, 2018

1. 01*

   Probing heavy neutrino oscillations in rare W boson decays

   Gorazd Cvetic🇨🇱 · Arindam Das🇰🇷 · Jilberto Zamora-Saa🇨🇱

   In this work, we study the lepton number violating W boson and top quark decays via intermediate on-shell Majorana neutrinos Nj into three charged leptons and a light neutrino. We discuss the neutrino oscillation effects present in the decay due to the small mass gap between the heavy neutrino states. We focus on a scenario that contains at least two heavy Majorana neutrinos in the mass range 2-80 GeV. The results indicate that the modulation of the branching ratios as a function of the distance between the vertices may be detected in a future experiment such as High-Luminosity Large Hadron Collider. As a secondary result, the CP-violating phases could be explored.

   hep-phJ.Phys.G(2019)·74 citations
2. 02*

   Freeze-out temperature from net-Kaon fluctuations at RHIC

   R. Bellwied🇺🇸 · J. Noronha-Hostler🇺🇸 · P. Parotto🇺🇸 · I. Portillo Vazquez🇺🇸 · C. Ratti🇺🇸 · J. M. Stafford🇺🇸

   We compare the mean-over-variance ratio of the net-kaon distribution calculated within a state-of-the-art hadron resonance gas model to the latest experimental data from the Beam Energy Scan at RHIC by the STAR collaboration. Our analysis indicates that it is not possible to reproduce the experimental results using the freeze-out parameters from the existing combined fit of net-proton and net-electric charge mean-over-variance. The strange mesons need about 10-15 MeV higher temperatures than the light hadrons at the highest collision energies. In view of the future $\Lambda$ fluctuation measurements, we predict the $\Lambda$ variance-over-mean and skewness-times-variance at the light and strange chemical freeze-out parameters. We observe that the $\Lambda$ fluctuations are sensitive to the difference in the freeze-out temperatures established in this analysis. Our results have implications for other phenomenological models in the field of relativistic heavy ion collisions.

   hep-phnucl-thPRC(2019)·69 citations
3. 03*

   Natural Higgs Inflation, Gauge Coupling Unification, and Neutrino Masses

   Heng-Yu Chen🇺🇸 · Ilia Gogoladze🇺🇸 · Shan Hu🇨🇳 · Tianjun Li🇨🇳 · Lina Wu🇨🇳

   We present a class of non-supersymmetric models in which so-called critical Higgs inflation ($\xi <100$) naturally can be realized without using specific values for Higgs and top quark masses. In these scenarios, the Standard Model (SM) vacuum stability problem, gauge coupling unification, neutrino mass generation and Higgs inflation mechanism are linked to each other. We adopt in our models Type I seesaw mechanism for neutrino masses. An appropriate choice of the Type I Seesaw scale allows us to have an arbitrarily small but positive value of SM Higgs quartic coupling around the inflation scale. We present a few benchmark points where we show that the scalar spectral indices are around 0.9626 and 0.9685 for the number of e-folding $N=50$ and $N=60$ respectively. The tensor-to-scalar ratios are order of $10^{-3}$. The running of the scalar spectral index is negative and is order of $10^{-4}$.

   hep-phInt.J.Mod.Phys.A(2020)·11 citations
4. 04*

   Lepton Flavor Violating Decays of $B$ and $K$ Mesons in Models with Extended Gauge Group

   Fayyazuddin🇵🇰 · M. Jamil Aslam🇵🇰 · Cai-Dian Lu🇨🇳

   Lepton Flavor Violating (LFV) decays are forbidden in the Standard Model (SM) and to explore them one has to go beyond it. The flavor changing neutral current induced Lepton Flavor Conserving and LFV decays of $K$ and $B$ mesons are discussed in the gauge group $G=SU(2{)}_L\times U(1{)}_{Y_1}\times SU(2{)}_X$. The lepto-quark $X_{\mu }^{\pm 2/3}$ corresponding to gauge group $SU(2{)}_X$ allows the quark-lepton transitions and hence giving a framework to construct the effective Lagrangian for the LFV decays. The mass of lepto-quark $m_X$ provides a scale at which the gauge group $G$ is broken to the SM gauge group. Using the most stringent experimental limit $\mathcal{B}(K_L^0\to {\mu }^{\mp }{e}^{\pm })<1.7\times 10^{-12}$, the upper bound on the effective coupling constant $(\frac{G_X}{G_F}{)}^2<1.1\times 10^{-10}$ is obtained for certain pairing of lepton and quark generations in the representation $(2,\bar{2})$ of the group $G$. Later, the effective Lagrangian for the LFV meson decays for the gauge group $G=\left[SU(2{)}_L\times SU(2{)}_R\times U(1{)}_{Y_1^{\prime }}\right]\times SU(2{)}_X$ is constructed. Using $\mathcal{B}(K^{-}\to {\pi }^{-}\nu \bar{\nu })=(1.7\pm 1.1)\times 10^{-10}$, the bound on the ratio of effective couplings is obtained to be ${\left(\frac{G_X}{G_F}\right)}^2<10^{-10}$. A number of decay modes are discussed which provide a promising area to test this model in the current and future particle physics experiments.

   hep-phInt.J.Mod.Phys.A(2018)·7 citations
5. 05*

   The large-mass regime of the dilaton-pion low-energy effective theory

   Maarten Golterman🇺🇸 · Yigal Shamir🇮🇱

   Numerical data of the SU(3) gauge theory with $N_f=8$ fermions in the fundamental representation suggest the existence of a large-mass regime, where the fermion mass is not small relative to the confinement scale, but nevertheless the dilaton-pion low-energy theory is applicable thanks to the parametric proximity of the conformal window. In this regime, the leading hyperscaling relations are similar to those of a mass-deformed conformal theory, so that distinguishing infrared conformality from confinement requires the study of subleading effects. Assuming that the $N_f=8$ theory confines, we estimate how light the fermion mass should be to enter the small-mass regime, where the pions become much lighter than the dilatonic scalar meson.

   hep-phhep-latPRD(2018)·73 citations
6. 06*

   Higgs inflation and cosmological electroweak phase transition with N scalars in the post-Higgs era

   Wei Cheng🇨🇳 · Ligong Bian🇨🇳

   We study inflation and cosmological electroweak phase transitions utilizing the Standard model augmented by $N$ scalars respecting a global $O(N)$ symmetry. We observe that the representation of the global symmetry is restricted by the inflationary observables and the condition of a strongly first order electroweak phase transition. Theoretical constraints including the stability, perturbativity and unitarity are used to bound the model parameter space. The Electroweak precision observables and Higgs precisions limit the representation of the symmetry. We evaluate the possibility to simultaneously address the inflation and the dark matter after considering the experimental constraints from the future leptonic colliders. When the $O(N)$ symmetry respected by the N-scalar is spontaneously broken to the $O(N-1)$ symmetry, both the one-step and two-step SFOEWPT can occur within the inflation viable parameter regions, which will be tested by the future CEPC, ILC and FCC-ee. The relation between the number of Goldstones and the SFOEWPT condition depends on phase transition patterns. The situation of Goldstone faking neutrinos and contributing to the dark radiation are investigated.

   hep-phPRD(2019)·19 citations
7. 07*

   Evaluating `elliptic' master integrals at special kinematic values: using differential equations and their solutions via expansions near singular points

   Roman N. Lee🇷🇺 · Alexander V. Smirnov🇷🇺 · Vladimir A. Smirnov🇷🇺

   This is a sequel of our previous paper where we described an algorithm to find a solution of differential equations for master integrals in the form of an $ϵ$-expansion series with numerical coefficients. The algorithm is based on using generalized power series expansions near singular points of the differential system, solving difference equations for the corresponding coefficients in these expansions and using matching to connect series expansions at two neighboring points. Here we use our algorithm and the corresponding code for our example of four-loop generalized sunset diagrams with three massive and two massless propagators, in order to obtain new analytical results. We analytically evaluate the master integrals at threshold, $p^2=9m^2$, in an expansion in $ϵ$ up to ${ϵ}^1$. With the help of our code, we obtain numerical results for the threshold master integrals in an $ϵ$-expansion with the accuracy of 6000 digits and then use the PSLQ algorithm to arrive at analytical values. Our basis of constants is build from bases of multiple polylogarithm values at sixth roots of unity.

   hep-phJHEP(2018)·49 citations
8. 08*

   Probing the Higgs sector of $Y=0$ Higgs Triplet Model at LHC

   M. Chabab🇲🇦 · M. C. Peyranère🇫🇷 · L. Rahili🇲🇦

   In this paper, we investigate the Higgs Triplet Model with hypercharge $Y_{\Delta }=0$ (HTM0), an extension of the Standard model, caracterised by a more involved scalar spectrum consisting of two CP even Higgs $h^0,H^0$ and two charged Higgs bosons $H^{\pm }$. We first show that the parameter space of HTM0, usually delimited by combined constraints originating from unitarity and BFB as well as experimental limits from LEP and LHC, is severely reduced when the modified Veltman conditions at one loop are also imposed. Then, we perform an rigorous analysis of Higgs decays either when $h^0$ is the SM-like or when the heaviest neutral Higgs $H^0$ is identified to the observed $125$ GeV Higgs boson at LHC. In these scenarios, we perform an extensive parameter scan, in the lower part of the scalar mass spectrum, with a particular focus on the Higgs to Higgs decay modes $H^0\to h^0{h}^0,H^{\pm }{H}^{\mp }$ leading predominantly to invisible Higgs decays. Finally, we also study the scenario where $h^0,H^0$ are mass degenerate. We thus find that consistency with LHC signal strengths favours a light charged Higgs with a mass about $176\sim 178$ GeV. Our analysis shows that the diphoton Higgs decay mode and $H\to Z\gamma$ are not always positively correlated as claimed in a previous study. Anti-correlation is rather seen in the scenario where $h$ is SM like, while correlation is sensitive to the sign of the potential parameter $\lambda$ when $H$ is identified to $125$ GeV Higgs.

   hep-phEPJC(2018)·37 citations
9. 09*

   The decay $h\to \gamma \gamma$ in the Standard-Model Effective Field Theory

   A. Dedes🇬🇷 · M. Paraskevas🇬🇷 · J. Rosiek🇵🇱 · K. Suxho🇬🇷 · L. Trifyllis🇬🇷

   Assuming that new physics effects are parametrized by the Standard-Model Effective Field Theory (SMEFT) written in a complete basis of up to dimension-6 operators, we calculate the CP-conserving one-loop amplitude for the decay $h\to \gamma \gamma$ in general $R_{\xi }$-gauges. We employ a simple renormalisation scheme that is hybrid between on-shell SM-like renormalised parameters and running $\overline{\mathrm{MS}}$ Wilson coefficients. The resulting amplitude is then finite, renormalisation scale invariant, independent of the gauge choice ($\xi$) and respects SM Ward identities. Remarkably, the $S$-matrix amplitude calculation resembles very closely the one usually known from renormalisable theories and can be automatised to a high degree. We use this gauge invariant amplitude and recent LHC data to check upon sensitivity to various Wilson coefficients entering from a more complete theory at the matching energy scale. We present a closed expression for the ratio ${\mathcal{R}}_{h\to \gamma \gamma }$, of the Beyond the SM versus the SM contributions as appeared in LHC $h\to \gamma \gamma$ searches. The most important contributions arise at tree level from the operators $Q_{\phi B},Q_{\phi W},Q_{\phi WB}$, and at one-loop level from the dipole operators $Q_{uB},Q_{uW}$. Our calculation shows also that, for operators that appear at tree level in SMEFT, one-loop corrections can modify their contributions by less than 10%. Wilson coefficients corresponding to these five operators are bounded from current LHC $h\to \gamma \gamma$ data -- in some cases an order of magnitude stronger than from other searches. Finally, we correct results that appeared previously in the literature.

   hep-phJHEP(2018)·71 citations
10. 10*

    Bound-state effects for dark matter with Higgs-like mediators

    Simone Biondini🇨🇭

    In this paper we study the impact of a scalar exchange on the dark matter relic abundance by solving a plasma-modified Schroedinger equation. A simplified model is considered where a Majorana dark matter fermion is embedded in a U(1)${}^{\prime }$ extension of the Standard Model and couples with a dark Higgs via a Yukawa interaction. We find that the dark-Higgs exchange can increase the overclosure bounds significantly. For the largest (smallest) value of the Yukawa coupling examined in this work, the dark matter mass is lifted from 5 TeV (0.55 TeV) to 27 TeV (0.70 TeV).

    hep-phJHEP(2018)·31 citations
11. 11*

    On anisotropy of the maximum attainable speed of low-mass particles

    B. Wojtsekhowski🇺🇸

    We evaluated the emission of a low-mass particle in the system (atomic) transition for the case when the particle Lorentz factor is $10^{18}$ and found that the angular distribution of emission in the laboratory inertial system is strongly affected by the directional variation of the maximum attainable speed of the particle. We show that for a photon mass consistent with the experimental limit, $m_{ph}\le 10^{-18}$ eV, due to the experimentally known absence of a significant anisotropy of the photon emission by an atom, the anisotropy of the one-way speed of light, $\Delta c_1/c$, is $10^{-37}$ or less. This is many orders of magnitude smaller than previously reported and the limit becomes even stronger for the lower mass of the photon.

    hep-ph0 citations
12. 12*

    Dark Matter Axion Clump Resonance of Photons

    Mark P. Hertzberg🇺🇸 · Enrico D. Schiappacasse🇺🇸

    Recently there has been interest in the physical properties of dark matter axion condensates. Due to gravitational attraction and self-interactions, they can organize into spatial localized clumps, whose properties were examined by us in Refs. [1, 2]. Since the axion condensate is coherently oscillating, it can conceivably lead to parametric resonance of photons, leading to exponential growth in photon occupancy number and subsequent radio wave emission. We show that while resonance always exists for spatially homogeneous condensates, its existence for a spatially localized clump condensate depends sensitively on the size of clump, strength of axion-photon coupling, and field amplitude. By decomposing the electromagnetic field into vector spherical harmonics, we are able to numerically compute the resonance from clumps for arbitrary parameters. We find that for spherically symmetric clumps, which are the true BEC ground states, the resonance is absent for conventional values of the QCD axion-photon coupling, but it is present for axions with moderately large couplings, or into hidden sector photons, or from scalar dark matter with repulsive interactions. We extend these results to non-spherically symmetric clumps, organized by finite angular momentum, and find that even QCD axion clumps with conventional couplings can undergo resonant decay for sufficiently large angular momentum. We discuss possible astrophysical consequences of these results, including the idea of a pile-up of clump masses and rapid electromagnetic emission in the sky from mergers.

    hep-phastro-ph.COastro-ph.GAgr-qc+1JCAP(2018)·130 citations
13. 13*

    Coulomb Potential Is Not a Part of The QCD Potential

    Gouranga C Nayak🇺🇸

    The Coulomb plus linear potential is widely used in QCD. However, in this paper we show that the Coulomb potential of the form $\frac{1}{r}$ is not a part of the QCD potential. This is because the form $\frac{g^2}{r}$ is for abelian theory (not QCD) and the form $\frac{g^2(\mu )}{r}$ in QCD at short distance is not of the Coulomb form $\frac{1}{r}$ because $g(\mu )$ depends on the mass/length scale $\mu$. Similarly at long distance the QCD potential corresponds to the potential in the classical Yang-Mills theory which does not have the Coulomb form $\frac{1}{r}$ because the fundamental color charge of the quark is time dependent in the classical Yang-Mills theory. This is unlike the QED potential which reduces to Coulomb potential at long distance.

    hep-phhep-latnucl-th0 citations
14. 14*

    Universal Imprints of a Pseudo-Nambu-Goldstone Higgs Boson

    Da Liu🇺🇸 · Ian Low🇺🇸 · Zhewei Yin🇺🇸

    A large class of models addressing the electroweak naturalness problem postulates the existence of new spontaneously broken global symmetries above the weak scale. The Higgs boson arises as a pseudo-Nambu-Goldstone boson (pNGB) whose interactions are nonlinear due to the presence of de- generate vacua. We argue that, once the normalization of the pNGB decay constant f is determined, the Higgs nonlinear interactions in the gauge sector are universal in the infrared and independent of the symmetry breaking pattern G/H, even after integrating out heavy composite resonances. We propose a set of "universal relations" in Higgs couplings with electroweak gauge bosons and in triple gauge boson couplings, which are unique predictions of the universal nonlinearity. Experimental measurements of these relations would serve as the litmus test of a pNGB Higgs boson.

    hep-phhep-exPRL(2018)·30 citations
15. 15*

    Galactic Rotation Curves vs. Ultra-Light Dark Matter: Implications of the Soliton -- Host Halo Relation

    Nitsan Bar🇮🇱 · Diego Blas🇨🇭 · Kfir Blum🇮🇱 · Sergey Sibiryakov🇨🇭

    Bosonic ultra-light dark matter (ULDM) would form cored density distributions at the center of galaxies. These cores, seen in numerical simulations, admit analytic description as the lowest energy bound state solution ("soliton") of the Schroedinger-Poisson equations. Numerical simulations of ULDM galactic halos found empirical scaling relations between the mass of the large-scale host halo and the mass of the central soliton. We discuss how the simulation results of different groups can be understood in terms of the basic properties of the soliton. Importantly, simulations imply that the energy per unit mass in the soliton and in the virialised host halo should be approximately equal. This relation lends itself to observational tests, because it predicts that the peak circular velocity, measured for the host halo in the outskirts of the galaxy, should approximately repeat itself in the central region. Contrasting this prediction to the measured rotation curves of well-resolved near-by galaxies, we show that ULDM in the mass range $m\sim (10^{-22}÷10^{-21})$ eV, which has been invoked as a possible solution to the small-scale puzzles of $\Lambda$CDM, is in tension with the data. We suggest that a dedicated analysis of the Milky Way inner gravitational potential could probe ULDM up to $m\lesssim 10^{-19}$ eV.

    ↳ astro-ph.COastro-ph.GAhep-phPRD(2018)·242 citations
16. 16*

    Quantum dissipation of a heavy quark from a nonlinear stochastic Schrödinger equation

    Yukinao Akamatsu🇯🇵 · Masayuki Asakawa🇯🇵 · Shiori Kajimoto🇯🇵 · Alexander Rothkopf🇩🇪

    We study the open system dynamics of a heavy quark in the quark-gluon plasma using a Lindblad master equation. Applying the quantum state diffusion approach by Gisin and Percival, we derive and numerically solve a nonlinear stochastic Schrödinger equation for wave functions, which is equivalent to the Lindblad master equation for the density matrix. From our numerical analysis in one spatial dimension, it is shown that the density matrix relaxes to the Boltzmann distribution in various setups (with and without external potentials), independently of the initial conditions. We also confirm that quantum dissipation plays an essential role not only in the long-time behavior of the heavy quark but also at early times if the heavy quark initial state is localized and quantum decoherence is ineffective.

    ↳ nucl-thhep-phquant-phJHEP(2018)·52 citations
17. 17*

    A general procedure for detector-response correction of higher order cumulants

    Toshihiro Nonaka🇨🇳 · Masakiyo Kitazawa🇯🇵 · ShinIchi Esumi🇯🇵

    We propose a general procedure for the detector-response correction (including efficiency correction) of higher order cumulants observed by the event-by-event analysis in heavy-ion collisions. This method makes use of the moments of the response matrix characterizing the property of a detector, and is applicable to a wide variety of response matrices such as those having non-binomial responses and including the effects of ghost tracks. A procedure to carry out the detector-response correction of realistic detectors is discussed. In test analyses, we show that this method can successfully re- construct the cumulants of true distribution for various response matrices including the one having multiplicity-dependent efficiency.

    ↳ physics.data-anhep-phnucl-exnucl-thNucl.Instrum.Meth.A(2018)·25 citations
18. 18*

    The photo-disintegration of ${}^4$He on the cosmic microwave background is less severe than earlier thought

    Jorge F. Soriano🇺🇸 · Luis A. Anchordoqui🇺🇸 · Diego F. Torres🇪🇸

    We thoroughly study the photo-disintegration of ${}^4$He on the cosmic microwave background using the most recent cross-section data both from the inclusive measurement observing the analog of the giant dipole resonance in ${}^4$He through the charge-exchange spin-flip ${}^4$He (${}^7$Li,${}^7$Be) reaction and from measurements of exclusive two-body and three-body processes: ${}^4\mathrm{He}(\gamma ,p){}^3\mathrm{H}$, ${}^4\mathrm{He}(\gamma ,n){}^3\mathrm{He}$, and ${}^4$He $(\gamma ,pn)$ ${}^2$H. We show that the present-day (redshift $z=0$) mean free path of ultra-relativistic (Lorentz factor $\sim 10^{10}$) helium nuclei increases by more that $15\%$ with respect to previous estimates adopted as benchmarks for Monte Carlo simulation codes of ultrahigh-energy cosmic ray propagation. This implies that the physical survival probability of ${}^4$He nuclei would be larger than predicted by existing event generators. For example, for $E\sim 10^{10.8}\mathrm{GeV}$ and a propagation distance of 3.5 Mpc, the ${}^4$He intensity would be $35\%$ larger than the output of CRPropa 3 program and $42\%$ larger than the output of SimProp v2r4 program. We provide new parametrizations for the two-body and three-body photo-disintegration cross-sections of ${}^4$He, ${}^3$He, tritium, and deuterium.

    ↳ astro-ph.HEhep-phPRD(2018)·15 citations
19. 19*

    Optimizing the ${}^8$Li yield for the IsoDAR Neutrino Experiment

    Adriana Bungau🇺🇸 · Jose Alonso🇺🇸 · Larry Bartoszek🇺🇸 · Janet Conrad🇺🇸 · Michael Shaevitz🇺🇸 · Joshua Spitz🇺🇸

    The focus of this paper is on optimizing the electron-antineutrino source for the IsoDAR (Isotope Decay at Rest) experimental program. IsoDAR will perform sensitive short-baseline neutrino oscillation and electroweak measurements, among other Beyond Standard Model searches, in combination with KamLAND and/or other suitable detectors. IsoDAR will rely on the high-$Q$ ${\beta }^{-}$ decay of the ${}^8$Li isotope for producing electron-antineutrinos, created mainly via neutron capture in an isotopically enriched ${}^7$Li sleeve surrounding the Be target. In particular, this paper examines the performance, defined in terms of absolute ${}^8$Li (or, equivalently, electron-antineutrino) production rate, of various candidate sleeve materials, including a lithium-fluoride, beryllium-fluoride mixture ("FLiBe") sleeve and a homogeneous mixture of lithium and beryllium ("Li-Be"). These studies show that the ${}^8$Li yield can be increased substantially by employing a Li-Be sleeve and therefore motivate significant changes to the nominal IsoDAR design.

    ↳ physics.ins-dethep-exhep-phphysics.acc-phJINST(2019)·16 citations
20. 20*

    Electric dipole moment of ${}^{199}$Hg atom from P, CP-odd electron-nucleon interaction

    Kota Yanase🇯🇵 · Naotaka Yoshinaga🇯🇵 · Koji Higashiyama🇯🇵 · Nodoka Yamanaka🇫🇷

    We calculate the effect of the P, CP-odd electron-nucleon interaction on the electric dipole moment of the ${}^{199}$Hg atom by evaluating the nuclear spin matrix elements in terms of the nuclear shell model. It is found that the neutron spin matrix element of the ${}^{199}$Hg nucleus is $⟨\Psi |{\sigma }_{nz}|\Psi ⟩\approx -0.4$ with a dominant configuration of $p_{1/2}$ orbital neutron. We also derive constraints on the CP phases of Higgs-doublet models, supersymmetric models, and leptoquark models from the latest experimental limit $|d_{\mathrm{Hg}}|<7.4\times 10^{-30}e$ cm.

    ↳ nucl-thhep-exhep-phphysics.atom-phPRD(2019)·42 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.