Tue·Jul 18, 2017Tuesday·July 18, 2017

1. 01*

   One-loop considerations for coexisting vacua in the CP conserving 2HDM

   A. L. Cherchiglia🇧🇷 · C. C. Nishi🇧🇷

   The Two-Higgs-Doublet model (2HDM) is a simple and viable extension of the Standard Model (SM) with a scalar potential complex enough that two minima may coexist. In this work we investigate if the procedure to identify our vacuum as the global minimum by tree-level formulas carries over to the one-loop corrected potential. In the CP conserving case, we identify two distinct types of coexisting minima --- the regular ones (moderate $\tan \beta$) and the non-regular ones (small or large $\tan \beta$) --- and conclude that the tree level expectation fails only for the non-regular type of coexisting minima. For the regular type, the sign of $m_{12}^2$ already precisely indicates which minima is the global one, even at one-loop.

   hep-phJHEP(2017)·4 citations
2. 02*

   Nonperturbative quark-gluon thermodynamics at finite density

   M.A. Andreichikov🇷🇺 · M.S. Lukashov🇷🇺 · Yu.A. Simonov🇷🇺

   Thermodynamics of the quark-gluon plasma at finite density is studied in the framework of the Field Correlator Method, where thermodynamical effects of Polyakov loops and colormagnetic confinement are taken into account. Having found good agreement with numerical lattice data for zero density, we calculate pressure $P(T,\mu )$ for $0<\mu <400$ MeV and $150<T<1000$ MeV. For the first time the explicit intergral form is found in this region,demonstrating analytic structure in the complex $\mu$ plane. The resulting multiple complex branch points are found at the Roberge-Weiss values of $\mathrm{Im}\mu$, with $\mathrm{Re}\mu$ defined by the values of Polyakov lines and colormagnetic confinement.

   hep-phhep-latInt.J.Mod.Phys.A(2018)·17 citations
3. 03*

   30 parameter version of the MSSM in light of the $B_s\to {\mu }^{+}{\mu }^{-}$ observation

   S.S. AbdusSalam🇮🇷 · L. Velasco-Sevilla🇳🇴

   The R-parity conserving MSSM in light of the decay $B_s\to {\mu }^{+}{\mu }^{-}$ with near-SM branching ratio is an interesting platform for studying the complementarity between direct and indirect searches for beyond the SM physics. Based on this, we have analysed the possible impact of the $B_s\to {\mu }^{+}{\mu }^{-}$ observation on the posterior sample from the global fit of a 30-parameter MSSM (MSSM-30), and the related Wilson Coefficients. The MSSM-30 is a systematically constructed, symmetry-guided, MSSM parametrization, as opposed to the traditional frames (e.g. pMSSM) with crude treatment of flavor violation parameters. This paper illustrates why phenomenological frames like the MSSM-30 should be preferred to study flavor physics. For the current and future B-physics experimental precision, such a consideration is crucial for suitably assessing supersymmetric contributions to flavor observables.

   hep-phPRD(2018)·2 citations
4. 04*

   Correct $\Delta m_{ij}^2$ Dependence for Neutrino Oscillation Formulae

   Randy A. Johnson🇺🇸

   The time translation operator for neutrino mass states is often taken to be $e^{-iEt/\hslash }$. This is not relativistically invariant. In kaon mixing, physicists use $e^{-im{c}^2\tau /\hslash }$ where $\tau$ is the proper time of the kaon state. The factor $m{c}^2\tau$ is the rest frame value of the four vector product $p_{\mu }{x}^{\mu }$ which is an invariant quantity. If $-i{p}_{\mu }{x}^{\mu }$ is used in neutrino oscillation formulae instead of $-iEt$, the scale of the $\Delta m_{ij}^2$ is reduced by a factor of two.

   hep-ph0 citations
5. 05*

   A minimal flavored $U(1{)}^{\prime }$ for $B$-meson anomalies

   Ligong Bian🇨🇳 · Soo-Min Choi🇰🇷 · Yoo-Jin Kang🇰🇷 · Hyun Min Lee🇰🇷

   We consider an anomaly-free $U(1{)}^{\prime }$ model with favorable couplings to heavy flavors in the Standard Model(SM), as motivated by $B$-meson anomalies at LHCb. Taking the $U(1{)}^{\prime }$ charge to be $Q^{\prime }=y(L_{\mu }-L_{\tau })+x(B_3-L_3)$, we can explain the $B$-meson anomalies without invoking extra charged fermions or flavor violation beyond the SM. We show that there is a viable parameter space with a small $x$ that is compatible with other meson decays, tau lepton and neutrino experiments as well as the LHC dimuon searches. We briefly discuss the prospects of discovering the $Z^{\prime }$ gauge boson at the LHC in the proposed model.

   hep-phPRD(2017)·54 citations
6. 06*

   Quasi-stationary states and fermion pair creation from a vacuum in supercritical Coulomb field

   V.R. Khalilov🇷🇺

   Creation of charged fermion pair from a vacuum in the so-called supercritical Coulomb potential is examined for the case when created pair moves in one plane. In which case the quantum dynamics of charged massive or massless fermions can be described by the two-dimensional Dirac Hamiltonians with a Coulomb potential. These Hamiltonians are singular and require the additional definition in order for them to be treated as self-adjoint quantum-mechanical operators. We construct the self-adjoint two-dimensional Dirac Hamiltonians with a Coulomb potential and determine the quantum-mechanical states for such Hamiltonians in the corresponding Hilbert spaces of square-integrable functions. We determine the scattering amplitude in which the self-adjoint extension parameter is incorporated and then obtain the equations implicitly defining the possible discrete energy spectra of the self-adjoint Dirac Hamiltonians with a Coulomb potential. It is shown that the quantum system in the presence of a supercritical Coulomb potential becomes unstable which manifests in the appearance of quasi-stationary states in the lower (negative) energy continuum. The energy spectrum of these states is quasi-discrete, consists of broadened levels whose width is related to the inverse lifetime of the quasi-stationary state as well as the creation probability of charged fermion pair by supercritical Coulomb field. Explicit analytical expressions for the creation probabilities of charged (massive or massless) fermion pair are obtained in a supercritical Coulomb field.

   hep-phquant-phMod.Phys.Lett.A(2017)·3 citations
7. 07*

   Multi-photon Effects in Single Nonlinear Compton Scattering and Single Nonlinear Breit-Wheeler Process in Ultra Intense Fields

   Bo Zhang🇨🇳 · Zhi-meng Zhang🇨🇳 · Zhi-gang Deng🇨🇳 · Wei Hong🇨🇳 · Jian Teng🇨🇳 · Shu-kai He🇨🇳 · Wei-min Zhou🇨🇳 · Yu-qiu Gu🇨🇳

   Nonlinear Compton scattering (NCS) and nonlinear Breit-Wheeler (NBW) process are strongly multi-photon and highly nonlinear processes. In ultra intense lasers (normalized field amplitude $a_0\gg 1$), radiation formation length is much shorter than a period and single NCS/NBW cannot be described as scatterings of electrons dressing plane waves with $\gamma$ photons for what they feel is a local constant crossed field. However, present theories in constant crossed fields are hard to give some important quantum features due to divergence problems, such as number of laser photons involved, instantaneous angular distribution and detailed spectrum. As an alternative, present understanding of single NCS/NBW in ultra intense lasers includes several classical and semi-quantum ideas such as forward emission, recoil reaction and spectrum cutoff. We investigated multi-photon effects on NCS/NBW in ultra intense lasers by extracting the number of laser photons involved in a single process in ultra intense lasers from formulae of existing theories. New features of single NCS in ultra intense lasers including fixed emission angle to instantaneous electron momentum, instantaneous deflection of electron, and disappearance of spectrum cutoff are deduced. Similar features of single NBW in ultra intense lasers including non-vanishing emission angles to instantaneous $\gamma$ photon momentum, disappearance of spectrum cutoff and appearance of spectrum lower limit are also obtained. Simulations show that corresponding signals of multi-photon effects are significant on $10$PW scale and stronger lasers.

   hep-ph0 citations
8. 08*

   Chiral symmetry and the properties of hadrons in the Generalised Nambu-Jona-Lasinio model

   Yu.S. Kalashnikova🇷🇺 · A.V. Nefediev🇷🇺 · J.E.F.T. Ribeiro🇵🇹

   Various aspects of the Generalised Nambu-Jona-Lasinio model for QCD in four dimensions are reviewed. The properties of mesonic excitations are discussed in detail, with special attention paid to the chiral pion. The spontaneous chiral symmetry breaking in the vacuum and the effective chiral symmetry restoration in the spectrum of highly excited mesons and baryons are described microscopically.

   hep-phhep-lathep-thnucl-thPhys.Usp.(2017)·6 citations
9. 09*

   Unquenching and unitarising mesons in quark models and on the lattice

   George Rupp🇵🇹 · Eef van Beveren🇵🇹

   Mesons with masses below their lowest OZI-allowed strong-decay thresholds have very small widths. Thus, it is usually believed that they can be safely treated as pure quark-antiquark bound states in spectroscopy models. However, unitarised and coupled-channel models from decades ago already indicated that this may not be the case, owing to significant virtual meson-loop contributions. Recent unquenched lattice calculations that include two-meson interpolators besides the usual $q\bar{q}$ ones confirm the latter conclusion, in particular for the enigmatic narrow $D_{s0}^{\star }(2317)$, $D_{s1}(2460)$, and $X(3872)$ states. Here, we briefly review some predictions of some old and new quark models that go beyond the static description of mesons, also in comparison with up-to-date lattice results.

   hep-phActa Phys.Polon.Supp.(2017)·1 citation
10. 10*

    To the nature of ${\chi }_{c2}(2P)$

    N.N. Achasov🇷🇺 · Xian-Wei Kang🇹🇼

    We expect that $BR({\chi }_{c2}(2P)\to gluongluon)\gtrsim 2\%$ if Particle Data Group as well as BaBar and Belle collaboration correctly identified the state. In reality, this branching ratio corresponds to the one for ${\chi }_{c2}(2P)$ decaying to the light hadrons. We also discuss the detection possibilities of these decays.

    hep-phhep-exCPC(2017)·3 citations
11. 11*

    Dihadron fragmentation functions in the quark-jet model: Longitudinally polarized quarks

    Hrayr H. Matevosyan🇦🇺 · Aram Kotzinian🇦🇲 · Anthony W. Thomas🇦🇺

    We study the dihadron fragmentation functions (DiFF) of longitudinally polarized quarks into pion pairs. The quark-jet framework is used to model the sequential hadronization of a polarized quark into hadrons, where the polarization transfer to the remnant quark in each hadron emission step is calculated using the spin density matrix formalism. Using Monte Carlo (MC) simulations of the hadronization process, we find a nonvanishing helicity dependent DiFF, $G_1^{\perp }$ , which is also related to the longitudinal jet handedness. A method is developed for extracting the angular moments of this DiFF, which enter the expressions for the azimuthal asymmetries for an electron-positron annihilation process into two pairs of hadrons from back-to-back jets and the dihadron production in semi-inclusive deep inelastic scattering. Finally, we derive explicit integral expressions for DiFFs where only two hadrons are emitted by a quark and use them to validate our MC results for both unpolarized and helicity dependent DiFFs.

    hep-phnucl-thPRD(2017)·24 citations
12. 12*

    Drag Force on Heavy Quarks and Spatial String Tension

    Oleg Andreev🇷🇺

    Heavy quark transport coefficients in a strongly coupled Quark-Gluon Plasma can be evaluated using a gauge/string duality and lattice QCD. Via this duality, one can argue that for low momenta the drag coefficient for heavy quarks is proportional to the spatial string tension. Such a tension is well studied on the lattice that allows one to straightforwardly make non-perturbative estimates of the heavy quark diffusion coefficients near the critical point. The obtained results are consistent with those in the literature.

    hep-phhep-lathep-thnucl-thMod.Phys.Lett.A(2018)·29 citations
13. 13*

    Parity doubling of baryons in a chiral approach with three flavors

    Chihiro Sasaki🇵🇱

    We formulate a set of mass relations for the baryon octet and decuplet with positive and negative parity in terms of the order parameter of QCD chiral symmetry. The Gell-Mann--Okubo mass formula and Gell-Mann's equal spacing rule hold manifestly in this approach. Thermal masses of the baryons are calculated in the mean field approximation for various pion masses, and the results are compared with the recent lattice studies. A general trend of the nucleon, $\Delta$ and $\Omega$ parity-doublers seen in the available lattice data can be understood qualitatively. Expected mass modifications of other strange baryons are also given with the physical and heavier pion masses.

    hep-phnucl-thNPA(2018)·29 citations
14. 14*

    Use of ANTARES and IceCube data to constrain a single power-law neutrino flux

    Marco Chianese🇮🇹 · Rosa Mele🇮🇹 · Gennaro Miele🇮🇹 · Pasquale Migliozzi🇮🇹 · Stefano Morisi🇮🇹

    We perform the first statistical combined analysis of the diffuse neutrino flux observed by ANTARES (nine-year) and IceCube (six-year) by assuming a single astrophysical power-law flux. The combined analysis reduces by a few percent the best-fit values for the flux normalization and the spectral index. Both data samples show an excess in the same energy range (40--200 TeV), suggesting the presence of a second component. We perform a goodness-of-fit test to scrutinize the null assumption of a single power-law, scanning different values for the spectral index. The addition of the ANTARES data reduces the $p$-value by a factor 2$÷$3. In particular, a single power-law component in the neutrino flux with the spectral index deduced by the six-year up-going muon neutrinos of IceCube is disfavored with a $p$-value smaller than $10^{-2}$.

    hep-phastro-ph.HEhep-exApJ(2017)·20 citations
15. 15*

    Transverse momentum spectrum of dilepton pair in the unpolarized ${\pi }^{-}N$ Drell-Yan process within TMD factorization

    Xiaoyu Wang🇨🇳 · Zhun Lu🇨🇳 · Ivan Schmidt🇨🇱

    We study the transverse momentum spectrum of dilepton produced in the unpolarized ${\pi }^{-}N$ Drell-Yan process, using transverse momentum dependent factorization up to next-to-logarithmic order of QCD. We extract the nonperturbative Sudakov form factor for the pion in the evolution formalism of the unpolarized TMD distribution function, by fitting the experimental data collected by the E615 Collaboration at Fermilab. With the extracted Sudakov factor, we calculate the normalized differential cross section with respect to transverse momentum of the dimuon and compare it with the recent measurement by the COMPASS Collaboration.

    hep-phhep-exJHEP(2017)·29 citations
16. 16*

    Interpreting IceCube 6-year HESE data as an evidence for hundred TeV decaying Dark Matter

    Marco Chianese🇮🇹 · Gennaro Miele🇮🇹 · Stefano Morisi🇮🇹

    The assumption of a single astrophysical power-law flux to explain the IceCube 6-year HESE extraterrestrial events yields a large spectral index that is in tension with gamma-ray observations and the 6-year up-going muon neutrinos data. Adopting a spectral index belonging to the range $\left[2.0,2.2\right]$, which is compatible with the one deduced by the analysis performed on the 6-year up-going muon neutrinos data and with $p$-$p$ astrophysical sources, the latest IceCube data show an up to $2.6\sigma$ excess in the number of events in the energy range 40--200 TeV. We interpret such an excess as a decaying Dark Matter signal and we perform a likelihood-ratio statistical test to compare the two-component scenario with respect to the single-component one.

    hep-phastro-ph.HEPLB(2017)·64 citations
17. 17*

    The IceCube low-energy excess: a Dark Matter interpretation

    Marco Chianese🇮🇹

    The recent study on the the 6-year up-going muon neutrinos by the IceCube Collaboration support the hypothesis of a two-component scenario explaining the diffuse TeV-PeV neutrino flux. Once a hard astrophysical power-law is considered, an excess in the IceCube data is shown in the energy range 10-100 TeV (low-energy excess}). By means of a statistical analysis on the neutrino energy spectrum and on the angular distribution of neutrino arrival directions, we characterize a two-component neutrino flux where decaying/annihilating Dark Matter particles provide a contribution to the IceCube observations.

    hep-phastro-ph.HENuovo Cim.C(2018)·1 citation
18. 18*

    Resolution Effects in the Hybrid Strong/Weak Coupling Model

    Zachary Hulcher🇺🇸 · Daniel Pablos🇨🇦 · Krishna Rajagopal🇺🇸

    Within the context of a hybrid strong/weak coupling model of jet quenching, we study the consequences of the fact that the plasma produced in a heavy ion collision cannot resolve the substructure of a collimated parton shower propagating through it with arbitrarily fine spatial resolution. We introduce a screening length parameter, $L_{\mathrm{res}}$, proportional to the inverse of the local temperature in the plasma, estimating a range for the value of the proportionality constant via comparing weakly coupled QCD calculations and holographic calculations appropriate in strongly coupled plasma. We then modify the hybrid model so that when a parton in a jet shower splits, its two offspring are initially treated as unresolved, and are only treated as two separate partons losing energy independently after they are separated by a distance $L_{\mathrm{res}}$. This modification delays the quenching of partons with intermediate energy, resulting in the survival of more hadrons in the final state with $p_T$ in the several GeV range. We analyze the consequences of different choices for the value of the resolution length, $L_{\mathrm{res}}$, and demonstrate that introducing a nonzero $L_{\mathrm{res}}$ results in modifications to the jet shapes and jet fragmentations functions, as it makes it more probable for particles carrying a small fraction of the jet energy at larger angles from the jet axis to survive their passage through the quark-gluon plasma. These effects are, however, small in magnitude, something that we confirm via checking for effects on missing-$p_T$ observables.

    hep-phJHEP(2018)·89 citations
19. 19*

    Identifying the nature of dark matter at $e^{-}{e}^{+}$ Colliders

    Nabil Baouche (1)🇩🇿 · Amine Ahriche (2) ((1) Ecole Normale Superieure, Algiers & U. Medea, (2) U. Jijel & ICTP, Trieste)🇩🇿

    In this work, we consider the process $e^{+}+e^{-}\to b\bar{b}+\text{slashed}{E}_T$, at the future electron-positron colliders such as the International Linear Collider and Compact Linear Collider, to look for the dark matter (DM) effect and identify its nature at two different center-of-mass energies $E_{c.m.}=500\mathrm{GeV}and1\mathrm{TeV}$. For this purpose, we take two extensions of the standard model, in which the DM could be a real scalar or a heavy right-handed neutrino (RHN) similar to many models motivated by neutrino mass. In the latter extension, the charged leptons are coupled to the RHNs via a lepton flavor violating interaction that involves a charged singlet scalar. After discussing different constraints, we define a set of kinematical cuts that suppress the background, and generate different distributions that are useful in identifying the DM nature. The use of polarized beams (like the polarization $P(e^{-},e^{+})=\left[+0.8,-0.3\right]$ at the International Linear Collider) makes the signal detection easier and the DM identification more clear, where the statistical significance gets enhanced by twice (five times) for scalar (RHN) DM.

    hep-phhep-exPRD(2017)·4 citations
20. 20*

    Extracting the mass scale of a second Higgs boson from a deviation in $h(125)$ couplings

    Simone Blasi🇮🇹 · Stefania De Curtis🇮🇹 · Kei Yagyu🇮🇹

    We investigate the correlation between a possible deviation in the discovered Higgs boson $h(125)$ couplings from the Standard Model prediction and the mass scale ($M_{\text{2nd}}$) of the next-to-lightest Higgs boson in models with non-minimal Higgs sectors. In particular, we comprehensively study a class of next-to-minimal Higgs sectors which satisfy the electroweak $\rho$ parameter to be one at tree level. We derive an upper limit on $M_{\text{2nd}}$ by imposing bounds from perturbative unitarity, vacuum stability, triviality and electroweak precision data as functions of the deviation in the $hVV$ ($V=W,Z$) couplings. Furthermore, we discuss the complementarity between these bounds and the current LHC data, e.g., by considering direct searches for additional Higgs bosons and indirect constraints arising from the measured $h(125)$ signal strengths.

    hep-phJHEP(2017)·8 citations
21. 21*

    Asymmetric Preheating

    Seishi Enomoto🇺🇸 · Tomohiro Matsuda🇯🇵

    We study the generation of the matter-antimatter asymmetry during bosonic preheating, focusing on the sources of the asymmetry. If the asymmetry appears in the multiplication factor of the resonant particle production, the matter-antimatter ratio will grow during preheating. On the other hand, if the asymmetry does not grow during preheating, one has to find out another reason. We consider several scenarios for the asymmetric preheating to distinguish the sources of the asymmetry. We also discuss a new baryogenesis scenario, in which the asymmetry is generated without introducing neither loop corrections nor rotation of a field.

    hep-phastro-ph.COhep-thInt.J.Mod.Phys.A(2018)·6 citations
22. 22*

    LHC Searches for Dark Sector Showers

    Timothy Cohen🇺🇸 · Mariangela Lisanti🇺🇸 · Hou Keong Lou🇺🇸 · Siddharth Mishra-Sharma🇺🇸

    This paper proposes a new search program for dark sector parton showers at the Large Hadron Collider (LHC). These signatures arise in theories characterized by strong dynamics in a hidden sector, such as Hidden Valley models. A dark parton shower can be composed of both invisible dark matter particles as well as dark sector states that decay to Standard Model particles via a portal. The focus here is on the specific case of 'semi-visible jets,' jet-like collider objects where the visible states in the shower are Standard Model hadrons. We present a Simplified Model-like parametrization for the LHC observables and propose targeted search strategies for regions of parameter space that are not covered by existing analyses. Following the 'mono-$X$' literature, the portal is modeled using either an effective field theoretic contact operator approach or with one of two ultraviolet completions; sensitivity projections are provided for all three cases. We additionally highlight that the LHC has a unique advantage over direct detection experiments in the search for this class of dark matter theories.

    hep-phJHEP(2017)·128 citations
23. 23*

    The $H_T$ Higgs boson at the LHC Run 2

    Paolo Cea🇮🇹

    We further elaborate on the proposal that the Higgs boson should be a broad heavy resonance, referred to as true Higgs $H_T$, with mass around $750GeV$. We stress once again that within the Standard Model the true Higgs is the unique possibility to implement the spontaneous symmetry breaking of the local gauge symmetry by elementary, relativistic and strictly local scalar fields. We discuss the most relevant decay modes of the $H_T$ boson and estimate they partial decay widths and branching ratios. We discuss briefly the experimental signatures of the $H_T$ Higgs boson and compare with the recent available LHC data at $\sqrt{s}=13TeV$. We find that the coupling of the $H_T$ Higgs boson to fermions is strongly suppressed. We also compare our theoretical expectations in the so-called golden channel to the data collected by the ATLAS and CMS Collaborations at $\sqrt{s}=13TeV$ with an integrated luminosity of $36.1f{b}^{-1}$ and $35.9f{b}^{-1}$ respectively. We find that our theoretical expectations are in fair good agreement with the experimental observations. Combining the data from both the LHC Collaborations we obtain an evidence of the heavy Higgs boson in this channel with an estimated statistical significance of more than three standard deviations. Finally, we argue that, if the signal is real, by the end of the Run 2 both the LHC experiments will reach in the golden channel a statistical significance of about five standard deviations.

    hep-phhep-ex3 citations
24. 24*

    Anatomy of $B_s\to PV$ decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

    Da-Cheng Yan🇨🇳 · Ping Yang🇨🇳 · Xin Liu🇨🇳 · Zhen-Jun Xiao🇨🇳

    In this paper, we will make systematic calculations for the branching ratios and the CP-violating asymmetries of the twenty one ${\bar{B}}_s^0\to PV$ decays by employing the perturbative QCD (PQCD) factorization approach. Besides the full leading-order (LO) contributions, all currently known next-to-leading order (NLO) contributions are taken into account. We found numerically that: (a) the NLO contributions can provide $\sim 40\%$ enhancement to the LO PQCD predictions for $\mathcal{B}({\bar{B}}_s^0\to K^0{\bar{K}}^{\ast 0})$ and $\mathcal{B}({\bar{B}}_s^0\to K^{\pm }{K}^{\ast \mp })$, or a $\sim 37\%$ reduction to $\text{calb}({\bar{B}}_s^0\to {\pi }^{-}{K}^{\ast +})$, and we confirmed that the inclusion of the known NLO contributions can improve significantly the agreement between the theory and those currently available experimental measurements, (b) the total effects on the PQCD predictions for the relevant $B\to P$ transition form factors after the inclusion of the NLO twist-2 and twist-3 contributions is generally small in magnitude: less than $10\%$ enhancement respect to the leading order result, (c) for the "tree" dominated decay ${\bar{B}}_s^0\to K^{+}{\rho }^{-}$ and the "color-suppressed-tree" decay ${\bar{B}}_s^0\to {\pi }^0{K}^{\ast 0}$, the big difference between the PQCD predictions for their branching ratios are induced by different topological structure and by interference effects among the decay amplitude ${\mathcal{A}}_{T,C}$ and ${\mathcal{A}}_P$: constructive for the first decay but destructive for the second one, and (d) for ${\bar{B}}_s^0\to V(\eta ,\text{etar})$ decays, the complex pattern of the PQCD predictions for their branching ratios can be understood by rather different topological structures and the interference effects between the decay amplitude $\text{cala}(V{\eta }_q)$ and $\text{cala}(V{\eta }_s)$ due to the $\eta -\text{etar}$ mixing.

    hep-phhep-exNPB(2018)·13 citations
25. 25*

    The Effective Field Theory of Large-Scale Structure in the presence of Massive Neutrinos

    Leonardo Senatore🇺🇸 · Matias Zaldarriaga🇺🇸

    We develop a formalism to analytically describe the clustering of matter in the mildly non-linear regime in the presence of massive neutrinos. Neutrinos, whose free streaming wavenumber ($k_{\mathrm{fs}}$) is typically longer than the non-linear scale ($k_{\mathrm{NL}}$) are described by a Boltzmann equation coupled to the effective fluid-like equations that describe dark matter. We solve the equations expanding in the neutrino density fraction $(f_{\nu })$ and in $k/k_{\mathrm{NL}}$, and add suitable counterterms to renormalize the theory. This allows us to describe the contribution of short distances to long-distance observables. Equivalently, we construct an effective Boltzmann equation where we add additional terms whose coefficients renormalize the contribution from short-distance physics. We argue that neutrinos with $k_{\mathrm{fs}}\gtrsim k_{\mathrm{NL}}$ require an additional counterterm similar to the speed of sound ($c_s$) for dark matter. We compute the one-loop total-matter power spectrum, and find that it is roughly equal to $16f_{\nu }$ times the dark matter one for $k$'s larger that the typical $k_{\mathrm{fs}}$. It is about half of that for smaller $k$'s. The leading contribution results from the back-reaction of the neutrinos on the dynamics of the dark matter. The counterterms contribute in a hierarchical way: the leading ones can either be computed in terms of $c_s$, or can be accounted for by shifting $c_s$ by an amount proportional to $f_{\nu }$.

    ↳ astro-ph.COhep-phhep-th107 citations
26. 26*

    Infrared fixed point of SU(2) gauge theory with six flavors

    Viljami Leino🇫🇮 · Kari Rummukainen🇫🇮 · Joni M. Suorsa🇫🇮 · Kimmo Tuominen🇫🇮 · Sara Tähtinen🇫🇮

    We compute the running of the coupling in SU(2) gauge theory with six fermions in fundamental representation of the gauge group. We establish an infrared stable fixed point at strong coupling and measure also the anomalous dimension of the fermion mass operator at the fixed point. This theory therefore likely lies close to the boundary of the conformal window and will display novel infrared dynamics if coupled with the electroweak sector of the Standard Model.

    ↳ hep-lathep-phPRD(2018)·24 citations
27. 27*

    Singular perturbation theory for the thermodynamic properties of holographic QCD

    Eugenio Megias🇪🇸 · Manuel Valle🇪🇸

    We explore the thermodynamics of a black-hole solution in improved holographic QCD with a simple dilaton potential having two parameters. By applying techniques of singular perturbation theory, we get uniform approximations for the metric and the dilaton field in the two regimes of big and small black-holes. These techniques lead to a resummation of the naive expansion at high temperatures, providing an important theoretical improvement with respect to previous results in the literature. By using this technique, it is shown how a quadratic dependence at low enough temperatures can naturally appear in the free energy. A comparison with lattice data of gluodynamics is performed. It is provided as well an estimate of the value of the gluon condensate at zero temperature which turns out to be in quite good agreement with the accepted values in the literature from phenomenological studies of QCD.

    ↳ hep-thgr-qchep-phFortsch.Phys.(2018)·5 citations
28. 28*

    Axion Stars and Repeating Fast Radio Bursts with Finite Bandwidths

    Aiichi Iwazaki🇯🇵

    We have proposed a model of non repeating fast radio bursts ( FRBs ); the collisions between axion stars and neutron stars generate the bursts. In this paper, we propose a model of repeating FRBs which shows that they arise from the several collisions between magnetized accretion disk of a black hole and an axion star orbiting the black hole. There would be many axions stars condensing as dark matter in an early stage galaxy so that such collisions arises repeatedly. The radiations are emitted by coherent oscillations of electrons in the accretion disk. The oscillations are caused by oscillating electric fields, which are induced by axion stars under strong magnetic field $\sim O(10^{11})$G. The emissions are terminated by the thermal fluctuations of the electrons which result from the thermalization of the oscillation energies. Although the radiations are monochromatic, the thermal Doppler effects broaden the spectral lines; their spectra $S(\nu )$ are given by $S(\nu )\propto \exp (-(\nu -{\nu }_c{)}^2/2(\delta \nu {)}^2)$ with the center frequency ${\nu }_c$. The bandwidth $\delta \nu ={\nu }_c\sqrt{T_c/m_e}$ with electron mass $m_e$ is determined by the critical temperature $T_c$ at which the thermal fluctuations terminate the coherent emissions. The observed bandwidths $(3\sim 5)\times 10^2$MHz are originated from the strong magnetic fields $\sim O(10^{11})$G. With such strong magnetic fields, large amount of the burst energies are produced. Various center frequencies ${\nu }_c$ of the bursts in the repeating FRB 121102 come from the various rotation speeds in the disk which make an intrinsic frequency of the bursts being Doppler shifted. The recent observation showing an extreme magneto-ionic environment around the source of FRB 121102 supports our model.

    ↳ astro-ph.HEhep-ph22 citations
29. 29*

    The "Folk Theorem" on Effective Field Theory: How Does It Fare in Nuclear Physics?

    Mannque Rho🇫🇷

    This is a brief history of what I consider as very important, some of which truly seminal, contributions made by young Korean nuclear theorists, mostly graduate students working on PhD thesis in 1990's and early 2000's, to nuclear effective field theory, nowadays heralded as the first-principle approach to nuclear physics. The theoretical framework employed is an effective field theory anchored on a scale-invariant hidden local symmetric Lagrangian constructed along the line of Weinberg's "Folk Theorem" on effective field theory. The problems addressed are the high-precision calculations on the thermal $np$ capture, the solar $pp$ fusion process, the solar $hep$ process -- John Bahcall's challenge to nuclear theorists -- and the quenching of $g_A$ in giant Gamow-Teller resonances and the whopping enhancement of first-forbidden beta transitions in astrophysical processes. Extending adventurously the strategy to a wild uncharted domain in which a systematic implementation of the "theorem" is far from obvious, the same effective Lagrangian is applied to the structure of compact stars. A surprising result on the properties of massive stars, totally different from what has been obtained up to day in the literature, is predicted, such as the precocious onset of conformal sound velocity together with the possible emergence of hidden symmetries such as scale symmetry and hidden local symmetry.

    ↳ nucl-thastro-ph.SRhep-phJ.Korean Phys.Soc.(2017)·2 citations
30. 30*

    Schwarzschild-de Sitter spacetime: the role of Temperature in the emission of Hawking radiation

    Thomas Pappas🇬🇷 · Panagiota Kanti🇬🇷

    We consider a Schwarzschild-de Sitter (SdS) black hole, and focus on the emission of massless scalar fields either minimally or non-minimally coupled to gravity. We use six different temperatures, two black-hole and four effective ones for the SdS spacetime, as the question of the proper temperature for such a background is still debated in the literature. We study their profiles under the variation of the cosmological constant, and derive the corresponding Hawking radiation spectra. We demonstrate that only few of these temperatures may support significant emission of radiation. We finally compute the total emissivities for each temperature, and show that the non-minimal coupling constant of the scalar field to gravity also affects the relative magnitudes of the energy emission rates.

    ↳ hep-thastro-ph.COgr-qchep-phPLB(2017)·43 citations
31. 31*

    From hadrons to quarks in neutron stars: a review

    Gordon Baym🇺🇸 · Tetsuo Hatsuda🇯🇵 · Toru Kojo🇨🇳 · Philip D. Powell🇺🇸 · Yifan Song🇺🇸 · Tatsuyuki Takatsuka🇯🇵

    We review the equation of state of matter in neutron stars from the solid crust through the liquid nuclear matter interior to the quark regime at higher densities. We focus in detail on the question of how quark matter appears in neutron stars, and how it affects the equation of state. After discussing the crust and liquid nuclear matter in the core we briefly review aspects of microscopic quark physics relevant to neutron stars, and quark models of dense matter based on the Nambu--Jona-Lasinio framework, in which gluonic processes are replaced by effective quark interactions. We turn then to describing equations of state useful for interpretation of both electromagnetic and gravitational observations, reviewing the emerging picture of hadron-quark continuity in which hadronic matter turns relatively smoothly, with at most only a weak first order transition, into quark matter with increasing density. We review construction of unified equations of state that interpolate between the reasonably well understood nuclear matter regime at low densities and the quark matter regime at higher densities. The utility of such interpolations is driven by the present inability to calculate the dense matter equation of state in QCD from first principles. As we review, the parameters of effective quark models -- which have direct relevance to the more general structure of the QCD phase diagram of dense and hot matter -- are constrained by neutron star mass and radii measurements, in particular favoring large repulsive density-density and attractive diquark pairing interactions. We describe the structure of neutron stars constructed from the unified equations of states with crossover. Lastly we present the current equations of state -- called "QHC18" for quark-hadron crossover -- in a parametrized form practical for neutron star modeling.

    ↳ astro-ph.HEhep-phnucl-exnucl-thRept.Prog.Phys.(2018)·970 citations
32. 32*

    Condensate of Massive Graviton and Dark Matter

    Katsuki Aoki🇯🇵 · Kei-ichi Maeda🇯🇵

    We study coherently oscillating massive gravitons in the ghost-free bigravity theory. This coherent field can be interpreted as a condensate of the massive gravitons. We first define the effective energy-momentum tensor of the coherent massive gravitons in a curved spacetime. We then study the background dynamics of the universe and the cosmic structure formation including the effects of the coherent massive gravitons. We find that the condensate of the massive graviton behaves as a dark matter component of the universe. From the geometrical point of view the condensate is regarded as a spacetime anisotropy. Hence, in our scenario, dark matter is originated from the tiny deformation of the spacetime. We also discuss a production of the spacetime anisotropy and find that the extragalactic magnetic field of a primordial origin can yield a sufficient amount for dark matter.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2018)·51 citations
33. 33*

    Covariant Information Theory and Emergent Gravity

    Vitaly Vanchurin🇺🇸

    Informational dependence between statistical or quantum subsystems can be described with Fisher matrix or Fubini-Study metric obtained from variations of the sample/configuration space coordinates. Using these non-covariant objects as macroscopic constraints we consider statistical ensembles over the space of classical probability distributions or quantum wave-functions. The ensembles are covariantized using dual field theories with either complex or real scalar fields identified with complex wave-functions or square root of probabilities. We argue that a full space-time covariance on a field theory side is dual to local computations on the information theory side. We define a fully covariant information-computation tensor and show that it must satisfy conservation equations. Then we switch to a thermodynamic description and argue that the (inverse of) space-time metric tensor is a conjugate thermodynamic variable to the ensemble-averaged information-computation tensor. In the equilibrium the entropy production vanishes and the metric is not dynamical, but away from equilibrium the entropy production gives rise to an emergent dynamics of the metric. This dynamics can be described by expanding the entropy production into products of generalized forces (derivatives of metric) and conjugate fluxes. Near equilibrium these fluxes are given by an Onsager tensor contracted with generalized forces and on the grounds of time-reversal symmetry the Onsager tensor is expected to be symmetric. We show that a particularly simple and highly symmetric form of the Onsager tensor gives rise to the Einstein-Hilbert term. This proves that general relativity is equivalent to a theory of non-equilibrium (thermo)dynamics of the metric which is expected to break down far away from equilibrium where the symmetries of the Onsager tensor are to be broken.

    ↳ hep-thcs.ITgr-qchep-ph+2Int.J.Mod.Phys.A(2018)·12 citations
34. 34*

    Recent CMS results in top and Higgs physics

    Rebeca Gonzalez Suarez🇺🇸

    After the Higgs boson discovery in 2012, the investigation of its properties and compatibility with the standard model predictions is central to the physics program of the LHC experiments. Likewise, the study of the top quark is still relevant at the LHC, more than two decades after its discovery at the Tevatron. Top quarks and Higgs bosons are produced at the LHC on a large scale and share a deep connection based on the large mass of the top quark. Both particles provide an excellent laboratory in which to search for new physics: the measurement of their properties tests the foundations of the standard model; and they feature prominently in a variety of exotic signals. The coupling of the Higgs boson to the top quark, a fundamental standard model parameter, can only be measured directly in processes where the two particles are produced together. The production of a Higgs boson together with one or two top quarks is also sensitive to several exciting new physics effects. A brief overview of the current experimental status of top quark and Higgs boson physics is presented using results from the CMS Collaboration.

    ↳ hep-exhep-phMod.Phys.Lett.A(2017)·1 citation
35. 35*

    The cosmic QCD phase transition with dense matter and its gravitational waves from holography

    M. Ahmadvand🇮🇷 · K. Bitaghsir Fadafan🇮🇷

    Consistent with cosmological constraints, there are scenarios with the large lepton asymmetry which can lead to the finite baryochemical potential at the cosmic QCD phase transition scale. In this paper, we investigate this possibility in the holographic models. Using the holographic renormalization method, we find the first order Hawking-Page phase transition, between Reissner-Nordstr$\ddot{\mathrm{o}}$m AdS black hole and thermal charged AdS space, corresponding to the de/confinement phase transition. We obtain the gravitational wave spectra generated during the evolution of bubbles for a range of the bubble wall velocity and examine the reliability of the scenarios and consequent calculations by gravitational wave experiments.

    ↳ hep-thgr-qchep-phPLB(2018)·31 citations
36. 36*

    Primordial perturbations from inflation with a hyperbolic field-space

    Shuntaro Mizuno🇯🇵 · Shinji Mukohyama🇯🇵

    We study primordial perturbations from hyperinflation, proposed recently and based on a hyperbolic field-space. In the previous work, it was shown that the field-space angular momentum supported by the negative curvature modifies the background dynamics and enhances fluctuations of the scalar fields qualitatively, assuming that the inflationary background is almost de Sitter. In this work, we confirm and extend the analysis based on the standard approach of cosmological perturbation in multi-field inflation. At the background level, to quantify the deviation from de Sitter, we introduce the slow-varying parameters and show that steep potentials, which usually can not drive inflation, can drive inflation. At the linear perturbation level, we obtain the power spectrum of primordial curvature perturbation and express the spectral tilt and running in terms of the slow-varying parameters. We show that hyperinflation with power-law type potentials has already been excluded by the recent Planck observations, while exponential-type potential with the exponent of order unity can be made consistent with observations as far as the power spectrum is concerned. We also argue that, in the context of a simple $D$-brane inflation, the hyperinflation requires exponentially large hyperbolic extra dimensions but that masses of Kaluza-Klein gravitons can be kept relatively heavy.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2017)·92 citations
37. 37*

    Strange Hadron Spectroscopy with a Secondary KL Beam at GlueX

    M.J. Amaryan (ODU) · M. Bashkanov (Edinburgh U.) · J. Ritman (Ruhr-U.) · J.R. Stevens (W&M) · I. Strakovsky (GWU) · GlueX Collaboration

    We propose to create a secondary beam of neutral kaons in Hall D at Jefferson Lab to be used with the GlueX experimental setup for strange hadron spectroscopy. A flux on the order of 3 x 10^4 KL/s will allow a broad range of measurements to be made by improving the statistics of previous data obtained on hydrogen targets by three orders of magnitude. Use of a deuteron target will provide first measurements on the neutron which is {\it terra incognita}. The experiment will measure both differential cross sections and self-analyzed polarizations of the produced {\Lambda}, {\Sigma}, {\Xi}, and {\Omega} hyperons using the GlueX detector at the Jefferson Lab Hall D. The measurements will span c.m. cos{\theta} from -0.95 to 0.95 in the c.m. range above W = 1490 MeV and up to 3500 MeV. These new GlueX data will greatly constrain partial-wave analyses and reduce model-dependent uncertainties in the extraction of strange resonance properties (including pole positions), and provide a new benchmark for comparisons with QCD-inspired models and lattice QCD calculations. The proposed facility will also have an impact in the strange meson sector by providing measurements of the final-state K{\pi} system from threshold up to 2 GeV invariant mass to establish and improve on the pole positions and widths of all K*(K{\pi}) P-wave states as well as for the S-wave scalar meson {\kappa}(800).

    ↳ hep-exhep-phnucl-exnucl-th18 citations
38. 38*

    Experimental summary of the $52^{\mathrm{nd}}$ Rencontres de Moriond session on Electroweak Interactions and Unified Theories

    Tim Gershon🇬🇧

    A summary, from an experimental perspective, of the $52^{\mathrm{nd}}$ Rencontres de Moriond session on Electroweak Interactions and Unified Theories is presented.

    ↳ hep-exhep-ph2 citations
39. 39*

    Magnetic Charge Search for the BELLE II Detector

    Michael K. Sullivan🇺🇸 · David Fryberger🇺🇸

    The introduction of magnetic charge into Maxwell's equations has led to an extensive search for magnetically charged particles (magnetic monopoles). A particle model developed by one of us (DF) adds an additional feature to Maxwell's symmetric equations in that the stable magnetic monopole should have the same charge strength as the electron. We have not found any experiments in high-energy physics that have explicitly ruled out this possibility. However, the few experiments at colliders that had no magnetic field might have observed a signal for these 1e strength magnetic monopoles as an unexpected enhancement in the mu+mu- production rate. The absence of any such observation leads us to set a tentative lower mass limit for these unit charge magnetic monopoles at 4.5-5 GeV/c2. Using a MC generator for magnetic charge and tracking these events through a simplified model of the BELLE II detector, we have found that the central drift chamber of BELLE II has a remarkably high efficiency for triggering on magnetically charged tracks. We suggest that the BELLE II collaboration perform a specific search for stable magnetically charged particles having a field strength of 1e when they run for the first time with colliding beams in 2018. This would be the first time anyone has specifically looked for such a particle.

    ↳ hep-exhep-ph8 citations
40. 40*

    The Cosmic Axion Spin Precession Experiment (CASPEr): a dark-matter search with nuclear magnetic resonance

    Antoine Garcon🇩🇪 · Deniz Aybas🇺🇸 · John W. Blanchard🇩🇪 · Gary Centers🇩🇪 · Nataniel L. Figueroa🇩🇪 · Peter W. Graham🇺🇸 · Derek F. Jackson Kimball🇺🇸 · Surjeet Rajendran🇺🇸 · Marina Gil Sendra🇩🇪 · Alexander O. Sushkov🇺🇸 · Lutz Trahms🇩🇪 · Tao Wang🇺🇸 and 3 other authors

    The Cosmic Axion Spin Precession Experiment (CASPEr) is a nuclear magnetic resonance experiment (NMR) seeking to detect axion and axion-like particles which could make up the dark matter present in the universe. We review the predicted couplings of axions and axion-like particles with baryonic matter that enable their detection via NMR. We then describe two measurement schemes being implemented in CASPEr. The first method, presented in the original CASPEr proposal, consists of a resonant search via continuous-wave NMR spectroscopy. This method offers the highest sensitivity for frequencies ranging from a few Hz to hundreds of MHz, corresponding to masses $m_{\mathrm{a}}\sim 10^{-14}$--$10^{-6}$ eV. Sub-Hz frequencies are typically difficult to probe with NMR due to the diminishing sensitivity of magnetometers in this region. To circumvent this limitation, we suggest new detection and data processing modalities. We describe a non-resonant frequency-modulation detection scheme, enabling searches from mHz to Hz frequencies ($m_{\mathrm{a}}\sim 10^{-17}$--$10^{-14}$ eV), extending the detection bandwidth by three decades.

    ↳ physics.ins-dethep-phphysics.app-phphysics.data-an+1Quantum Sci.Technol.(2017)·100 citations
41. 41*

    Spontaneous conformal symmetry breaking and a massless Wu-Yang monopole

    Marc Gillioz🇨🇭

    A formulation of $\mathcal{N}=2$ supersymmetric Yang-Mills theory with a spacetime-dependent gauge coupling allows to study the breaking of conformal symmetry at the quantum level. The theory has an energy-momentum tensor that is only conserved if an equation of motion for the coupling is imposed. It admits non-trivial solitons, among which the Wu-Yang monopole that can be regularized and turns out to be massless. On the other hand, the ordinary BPS monopole is only a solution in the large $N_c$ limit.

    ↳ hep-thhep-ph4 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.