Tue·Apr 24, 2018Tuesday·April 24, 2018

1. 01*

   Non-minimal coupling contribution to DIS at low $x$ in Holographic QCD

   Artur Amorim🇵🇹 · Robert Carcassés Quevedo🇵🇹 · Miguel Costa🇵🇹

   We consider the effect of including a non-minimal coupling between a $U(1)$ vector gauge field and the graviton Regge trajectory in holographic QCD models. This coupling describes the QCD interaction between the quark bilinear electromagnetic current and the Pomeron. We test this new coupling against DIS data at low Bjorken $x$ and obtain an excellent fit with a chi squared of 1.1 over a very large kinematical range in the photon virtuality $Q^2<400{\mathrm{GeV}}^2$ and for $x<10^{-2}$. The scale of the new dimension full coupling, which arises from integrating higher spin fields, is of order $6\mathrm{GeV}$. This value matches precisely the expectations from effective field theory, which indicate that such corrections are controlled by the mass gap between the spin two and spin four glueballs that are described holographically by the graviton and spin four field in the graviton Regge trajectory, respectively

   hep-phhep-thPRD(2018)·13 citations
2. 02*

   Seesaw Scale, Unification, and Proton Decay

   Pavel Fileviez Perez🇺🇸 · Axel Gross🇺🇸 · Clara Murgui🇪🇸

   We investigate a simple realistic grand unified theory based on the $SU(5)$ gauge symmetry which predicts an upper bound on the proton decay lifetime for the channels $p\to K^{+}\bar{\nu }$ and $p\to {\pi }^{+}\bar{\nu }$, i.e. $\tau (p\to K^{+}\bar{\nu })\lesssim 3.4\times 10^{35}$ and $\tau (p\to {\pi }^{+}\bar{\nu })\lesssim 1.7\times 10^{34}$ years, respectively. In this context, the neutrino masses are generated through the type I and type III seesaw mechanisms, and one predicts that the field responsible for type III seesaw must be light with a mass below 500 TeV. We discuss the testability of this theory at current and future proton decay experiments.

   hep-phhep-exhep-thPRD(2018)·19 citations
3. 03*

   Dark photon portal dark matter with the 21-cm anomaly

   Lian-Bao Jia🇨🇳

   A strong absorption profile was reported by the EDGES Collaboration, which indicates the hydrogen gas being colder than expected. It could be signatures of non-gravitational interactions between normal matter and dark matter (DM), and a potential explanation is that a small fraction of millicharged DM scatters with normal matter, with the DM mass in tens of MeV. To obtain the small fraction of millicharged DM and meanwhile being tolerant with by the constraints, the dark photon portal scalar and vector millicharged DM are explored in this paper. We consider that the mass of dark photon is slightly above twice of the millicharged DM mass, and thus the millicharged DM predominantly annihilates in p-wave during the freeze-out period, with the annihilation being enhanced near the resonance. The dark photon mainly decays into millicharged DM, and couplings of dark photon with SM particles could be allowed by the lepton collision experiments. The corresponding parameter spaces are derived. Future lepton collision experiments can be employed to search for millicharged DM via the production of the invisible dark photon.

   hep-phastro-ph.COEPJC(2019)·25 citations
4. 04*

   Geometric IR subtraction for real radiation

   Franz Herzog🇳🇱

   A scheme is proposed for the subtraction of soft and collinear divergences present in massless real emission phase space integrals. The scheme is based on a local slicing procedure which utilises the soft and collinear factorisation properties of amplitudes to produce universal counter-terms whose analytic integration is relatively simple. We propose that this scheme can be promoted to a fully local subtraction method. As a first application the scheme is applied to establish a general pole formula for final state real radiation at NLO and NNLO in Yang Mills theory for arbitrary multiplicities. All required counter-terms are evaluated to all orders in the dimensional regulator in terms of $\Gamma$ - and ${}_p{F}_q$ hypergeometric - functions. As a proof of principle the poles in the dimensional regulator of the $H\to gggg$ double real emission contribution to the $H\to gg$ decay rate are reproduced.

   hep-phhep-thJHEP(2018)·100 citations
5. 05*

   Electrical conductivity of Hot and Dense QCD matter at RHIC BES energies: A Color String Percolation Approach

   Pragati Sahoo🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Raghunath Sahoo🇮🇳

   Recently, transport coefficients viz. shear viscosity, electrical conductivity etc. of strongly interacting matter produced in heavy-ion collisions have drawn considerable interest. We study the normalised electrical conductivity (${\sigma }_{\mathrm{el}}$/T) of hot QCD matter as a function of temperature (T) using the Color String Percolation Model (CSPM). We also study the temperature dependence of shear viscosity and its ratio with electrical conductivity for the QCD matter. We compare CSPM estimations with various existing results and lattice Quantum Chromodynamics (lQCD) predictions with (2+1) dynamical flavours. We find that ${\sigma }_{\mathrm{el}}$/T in CSPM has a very weak dependence on the temperature. We compare CSPM results with those obtained in Boltzmann Approach to Multi-Parton Scatterings (BAMPS) model. A good agreement is found between CSPM results and predictions of BAMPS with fixed strong coupling constant.

   hep-phhep-exnucl-exnucl-thPRD(2018)·21 citations
6. 06*

   Resolution of $R_D$/$R_{D^{\ast }}$ puzzle

   Ashutosh Kumar Alok🇮🇳 · Dinesh Kumar🇮🇳 · Suman Kumbhakar🇮🇳 · S Uma Sankar🇮🇳

   One of the exciting results in flavor physics in recent times is the $R_D$/$R_{D^{\ast }}$ puzzle. The measurements of these flavor ratios performed by the B-factory experiments, BaBar and Belle, and the LHCb experiment are about $4\sigma$ away from the Standard Model expectation. These measurements indicate that the mechanism of $b\to c\tau \bar{\nu }$ decay is not identical to that of $b\to c(\mu /e)\bar{\nu }$. This charge lepton universality violation is particularly intriguing because these decays occur at tree level in the Standard Model. In particular, we expect a moderately large new physics contribution to $b\to c\tau \bar{\nu }$. The different types of new physics amplitudes, which can explain the $R_D$/$R_{D^{\ast }}$ puzzle, have been identified previously. In this letter, we show that the polarization fractions of $\tau$ and $D^{\ast }$ and the angular asymmetries $A_{FB}$ and $A_{LT}$ in $B\to D^{\ast }\tau \bar{\nu }$ decay have the capability to uniquely identify the Lorentz structure of the new physics. A measurement of these four observables will lead to such an identification.

   hep-phhep-exPLB(2018)·32 citations
7. 07*

   Analyses of multiplicity distributions and Bose-Einstein correlations at the LHC using negative binomial distribution and generalized Glauber-Lachs formula

   Minoru Biyajima🇯🇵 · Takuya Mizoguchi🇯🇵

   This study aims to analyze the data on multiplicity distributions and Bose-Einstein correlations collected at the LHC by the ATLAS and CMS Collaborations using a double-generalized Glauber-Lachs formula (D-GGL) and double-negative binomial distribution (D-NBD). From this investigation, it can be inferred that the D-GGL formula performs as effectively as the D-NBD. Moreover, our results show that the parameters estimated in multiplicity distributions (MD) (P(n)) are related to those contained in the BEC formula.

   hep-phnucl-thEPJA(2018)·7 citations
8. 08*

   Universality and Regge-like spectroscopy for orbitally-excited light mesons

   Duojie Jia🇨🇳 · Wen-Chao Dong🇨🇳

   A new Regge-like mass relation for excited light mesons is presented in relativized quark model which supports an universality that the quark mass dependence of the light meson spectroscopy is suppressed significantly and the confining parameter is nearly family independent. It is obtained by using auxiliary field method and quasi-linearizing the solution to the mass relation solved from the model. The resulted mass predictions are in good agreement with the observed masses for the orbitally-excited trajectory family of $\pi /b$, $\rho /a$, $\eta /h$, $\omega /f$, $K^{\ast }$ and $\varphi /f^{\prime }$. A semiclassical argument is given that the inverse slopes on the radial and angular-momentum Regge trajectories are equal in the massless limit of quarks.

   hep-ph2 citations
9. 09*

   NNLOPS accurate associated HZ production with NLO decay $\mathrm{H}\to b\bar{b}$

   William Astill🇬🇧 · Wojciech Bizon🇬🇧 · Emanuele Re🇨🇭 · Giulia Zanderighi🇨🇭

   We present a next-to-next-to-leading order (NNLO) accurate description of associated HZ production, followed by the Higgs boson decay into a pair of $b$-quarks treated at next-to-leading order (NLO), consistently matched to a parton shower (PS). The matching is achieved by performing reweighting of the $\text{HZJ-MiNLO}$ events, using multi-dimensional distributions that are fully-differential in the HZ Born kinematics, to the NNLO results obtained by using the $\text{MCFM-8.0}$ fixed-order calculation. Additionally we include the $gg\to \mathrm{HZ}$ contribution to the discussed process that appears at the $\mathcal{O}({\alpha }_s^2)$. We present phenomenological results obtained for 13 TeV hadronic collisions.

   hep-phhep-exJHEP(2018)·59 citations
10. 10*

    Matching of transverse momentum dependent distributions at twist-3

    Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇩🇪

    We derive the leading order matching of the quark generated polarized transverse momentum dependent (TMD) distributions onto the collinear functions at small values of the transverse distance. Starting from the very definition of the TMD operator and performing the light-cone operator product expansion up to twist-3 order, we evaluate each distribution directly in position space. We primarily consider the cases of Sivers, Boer-Mulders and worm-gear functions. The effects of the TMD process dependence on the matching are explicitly shown. We also discuss the moments of TMD distributions which can be relevant for lattice calculations.

    hep-phhep-exhep-latnucl-ex+1EPJC(2018)·48 citations
11. 11*

    Simplified Gaugino-Higgsino Models in the MSSM

    M.P.A. Sunder🇩🇪

    We present a tool to produce benchmarks with realistic mass spectra and realistic mixing in the gaugino-higgsino sector of the MSSM. We suggest as a next-to-minimal approach the use of benchmarks, whose mass spectra and mixing matrix elements are the result of a proper matrix diagonalisation at treelevel. We scan over the four relevant parameters $\{\mu ,\tan \beta ,M_1,M_2\}$ for a specific grid of neutralino and chargino masses. We demonstrate how to define a measure for the quality of a fit, including a method to maximise properties such as the gaugino or higgsino content.

    hep-ph0 citations
12. 12*

    Systematic twist expansion of $({\eta }_c,{\eta }_b)\to {\gamma }^{\ast }\gamma$ transition form factors in light-front quark model

    Hui-Young Ryu (Pusan National Univ.)🇰🇷 · Ho-Meoyng Choi (Kyungpook National Univ.)🇰🇷 · Chueng-Ryong Ji (North Carolina State Univ.)🇺🇸

    The light-front quark model analysis of the meson-photon transition form factor $F_{P\gamma }(Q^2)$ amenable both for the spacelike region ($Q^2>0$) and the timelike region ($Q^2<0$) provides a systematic twist expansion of $Q^2{F}_{P\gamma }(Q^2)$ for the high $|Q^2|$ region. Investigating $F_{P\gamma }(Q^2)(P={\eta }_c,{\eta }_b)$ for the entire kinematic regions of $Q^2$, we examine the twist-2 and twist-3 distribution amplitudes of $({\eta }_c,{\eta }_b)$ mesons in the light-front quark model and quantify their contributions to $Q^2{F}_{({\eta }_c,{\eta }_b)\gamma }(Q^2)$. Our numerical results for the normalized transition form factor $F_{({\eta }_c,{\eta }_b)\gamma }(Q^2)/F_{({\eta }_c,{\eta }_b)\gamma }(0)$ and the decay width ${\Gamma }_{({\eta }_c,{\eta }_b)\to \gamma \gamma }$ are compared with the available data checking the sensitivity of our model to the variation of the constituent quark masses.

    hep-phPRD(2018)·16 citations
13. 13*

    Polarized gamma rays from dark matter annihilations

    Wei-Chih Huang🇩🇰 · Kin-Wang Ng🇹🇼

    In this paper, we explore the possibility of a linearly polarized gamma-ray signal from dark matter annihilations in the Galactic center. Considering neutral weakly interacting massive particles, a polarized gamma-ray signal can be realized by a two-component dark matter model of Majorana fermions with an anapole moment. We discuss the spin alignment of such dark matter fermions in the Galactic center and then estimate the intensity and the polarizability of the final-state electromagnetic radiation in the dark matter annihilations. For low-mass dark matter, the photon flux at sub-GeV energies may be polarized at a level detectable in current X-ray polarimeters. Depending on the mass ratio between the final-state fermion and DM, the degree of polarization at the mass threshold can reach $70\%$ or even higher, providing us with a new tool for probing the nature of dark matter in future gamma-ray polarization experiments.

    hep-phastro-ph.HEPLB(2018)·7 citations
14. 14*

    The spectroscopy of solar sterile neutrinos

    Ilídio Lopes🇵🇹

    We predict the sterile neutrino spectrum of some of the key solar nuclear reactions and discuss the possibility of these being observed by the next generation of solar neutrino experiments. By using an up-to-date standard solar model with good agreement with current helioseismology and solar neutrino flux data sets, we found that from solar neutrino fluxes arriving on Earth only 3\%-4\% correspond to the sterile neutrino. The most intense solar sources of sterile neutrinos are the $pp$ and ${}^{7}Be$ nuclear reactions with a total flux of $2.2\times 10^9\mathrm{c}{\mathrm{m}}^2{\mathrm{s}}^{-1}$ and $1.8\times 10^8\mathrm{c}{\mathrm{m}}^2{\mathrm{s}}^{-1}$, followed by the ${}^{13}N$ and ${}^{15}O$ nuclear reactions with a total flux of $1.9\times 10^7\mathrm{c}{\mathrm{m}}^2{\mathrm{s}}^{-1}$ and $1.7\times 10^7\mathrm{c}{\mathrm{m}}^2{\mathrm{s}}^{-1}$. Moreover, we compute the sterile neutrino spectra of the nuclear proton-proton nuclear reactions -- $pp$, $hep$ and ${}^{8}B$ and the carbon-nitrogen-oxygen -- ${}^{13}N$, ${}^{15}O$ and ${}^{17}F$ and the spectral lines of ${}^{7}Be$.

    hep-phastro-ph.SREPJC(2018)·3 citations
15. 15*

    Bottomonium suppression in nucleus-nucleus collisions using effective fugacity quasi-particle model

    Indrani Nilima🇮🇳 · Vineet Kumar Agotiya🇮🇳

    In the present article, we have studied the equation of state and dissociation temperature of bottomonium state by correcting the full Cornell potential in isotropic medium by employing the effective fugacity quasi-particle Debye mass. We had also calculated the bottomonium suppression in an expanding, dissipative strongly interacting QGP medium produced in relativistic heavy-ion collisions. Finally we compared our results with experimental data from RHIC 200GeV/nucleon Au-Au collisions, LHC 2.76 TeV/nucleon Pb-Pb, and LHC 5.02 TeV/nucleon Pb-Pb collisions as a function of number of participants

    hep-phAdv.High Energy Phys.(2018)·4 citations
16. 16*

    Time-dependent rate of multicomponent dark matter: Reproducing the DAMA/LIBRA phase-2 results

    Juan Herrero-Garcia🇦🇺 · Andre Scaffidi🇦🇺 · Martin White🇦🇺 · Anthony G. Williams🇦🇺

    The current paradigm for dark matter direct detection is to assume that the dark sector is solely composed of a single particle species. In this short paper, we make the observation that dark matter comprising both a light and a heavy component that modulate out of phase leads to interesting phenomenology in annual modulation experiments. For an illustrative example, we use the recently released DAMA/LIBRA phase-2 results with a lower energy threshold. Immediately after, it was argued that a one-component spin-independent dark matter explanation of the observed annual modulation is strongly disfavored or excluded unless isospin-violating couplings are invoked. We show that a simple two-component extension can reproduce the observed spectrum without the need to invoke fine-tuned couplings. Using the publicly available DAMA/LIBRA data, we perform a fit of the DAMA/LIBRA energy spectrum of the annual modulation amplitude to a scenario with two dark matter components. We also take into account how gravitational focusing affects the phases of the light and a heavy components differently, which leads to nontrivial effects in the total time-dependent rate. Our results show that there exists a unique solution in agreement with the data in the simplest case of isospin-conserving couplings with equal cross sections. The distinctive features found in this work are crucial for a dark matter interpretation of any observed annual modulation.

    hep-phastro-ph.COPRD(2018)·24 citations
17. 17*

    Detection techniques and investigation of different neutrino experiments

    Ankur Nath🇮🇳 · Ng. K. Francis🇮🇳

    Neutrino physics is an experimentally driven field. So, we investigate the different detection techniques available in the literature and study the various neutrino oscillation experiments in a chronological manner. Our primary focus is on the construction and detection mechanisms of each experiment. Today, we know a lot about this mysterious ghostly particle by performing different experiments at different times with different neutrino sources viz. solar, atmospheric, reactor, accelerators and high energy astrophysical; and they have contributed in the determination of neutrino parameters. Yet the problems are far from over. We need to determine more precise values of the already known parameters and unravel the completely unknown parameters. Some of the unknowns are absolute masses of neutrino, types of neutrino, mass hierarchy, octant degeneracy and existence of leptonic CP Phase(s). We analyse the neutrino experiments into the past, present and the future (or proposed). We include SNO, Kamiokande, K2K, MINOS, MINOS+, Chooz, NEMO and ICARUS in the past; while Borexino, Double Chooz, Super-K, T2K, IceCube, KamLAND, NO$\nu$A, RENO and Daya Bay in the present; and SNO+, Hyper-K, JUNO, RENO-50, INO, DUNE, SuperNEMO, KM3NeT, P2O, LBNO and PINGU in the proposed experiments. We also discuss the necessities of upgrading the present ones to those of the proposed ones thereby summarizing the potentials of the future experiments. We conclude this paper with the current status of the neutrinos.

    hep-phhep-exphysics.ins-detInt.J.Mod.Phys.A(2021)·13 citations
18. 18*

    On the angular distribution of ${\Lambda }_b\to \Lambda (\to N\pi ){\tau }^{+}{\tau }^{-}$ decay

    Diganta Das🇮🇳

    We present a full angular distribution of the four body ${\Lambda }_b\to \Lambda (\to N\pi ){\ell }^{+}{\ell }^{-}$ decay where the leptons are massive and the ${\Lambda }_b$ is unpolarized, in an operator basis which includes the Standard Model operators, new vector and axial-vector operators, and scalar and pseudo-scalar operators. The angular coefficients are expressed in terms of transversity amplitudes. We study several ${\Lambda }_b\to \Lambda (\to p\pi ){\tau }^{+}{\tau }^{-}$ observables in the Standard Model and in the presence of the new operators. For our numerical analysis, we use the form factors from lattice QCD calculations.

    hep-phJHEP(2018)·36 citations
19. 19*

    Covariant quark model for the electromagnetic structure of light nucleon resonances

    G. Ramalho🇧🇷

    We present estimates from the covariant spectator quark model for the electromagnetic transition form factors for the resonances $N(1440){\frac{1}{2}}^{+}$, $N(1535){\frac{1}{2}}^{-}$, $N(1520){\frac{3}{2}}^{-}$ and $\Delta (1232){\frac{3}{2}}^{+}$, at intermediate and large square momentum transfer ($Q^2$). The calculations associated to the $N(1440){\frac{1}{2}}^{+}$, $N(1535){\frac{1}{2}}^{-}$ and $N(1520){\frac{3}{2}}^{-}$ states are based exclusively on the parametrizations derived for the nucleon. In the case of the $\Delta (1232){\frac{3}{2}}^{+}$ (isospin 3/2), we use lattice QCD data to estimate the radial structure, and take into account the well known effects associated with the pion cloud dressing of the baryons. Our estimates are based mainly on the valence quark degrees of freedom and are in good agreement with the data for $Q^2>2$ GeV${}^2$, with a few exceptions. The present predictions can be tested in a near future for large $Q^2$ at the Jefferson Lab -- 12 GeV upgrade.

    hep-phhep-exhep-latnucl-ex+10 citations
20. 20*

    Lattice QCD and heavy ion collisions: a review of recent progress

    Claudia Ratti🇺🇸

    In the last few years, numerical simulations of QCD on the lattice have reached a new level of accuracy. A wide range of thermodynamic quantities is now available in the continuum limit and for physical quark masses. This allows a comparison with measurements from heavy ion collisions for the first time. Furthermore, calculations of dynamical quantities are also becoming available. The combined effort from first principles and experiment allows us to gain an unprecedented understanding of the properties of quark-gluon plasma. I will review the state-of-the-art results from lattice simulations and connect them to the experimental information from RHIC and the LHC.

    ↳ hep-lathep-phnucl-thRept.Prog.Phys.(2018)·275 citations
21. 21*

    Towers of baryons of the $\mathcal{N}=2$ quark model band in the large $N_c$ limit

    C.T. Willemyns🇦🇷 · N.N. Scoccola🇦🇷

    We performed a complete analysis of the spectrum of all the states in the $\mathcal{N}=2$ quark model harmonic oscillator band with $N_f=3$ in the large $N_c$ limit including the often disregarded antisymmetric multiplet $[20,1^{+}]$. We included configuration mixing effects. We found that the states in the $[56,L^{+}]$ and $[70,L^{+}]$ with $L=0,2$ fall into nine towers of degenerate states. We found that nonstrange antisymmetric states fall into three towers and respond to the same structure as the states in the $[70,1^{-}]$ multiplet. We also showed explicitly the compatibility of these results and the scattering resonance picture.

    ↳ nucl-thhep-lathep-phPRD(2018)·1 citation
22. 22*

    Imprint of entanglement entropy in the power spectrum of inflationary fluctuations

    Daniel Boyanovsky🇺🇸

    If the inflaton couples to other degrees of freedom that populate the post-inflationary stage, such coupling modifies the dynamics of the inflaton \emph{during} inflation. We consider light fermions Yukawa coupled to the inflaton as "unobserved" degrees of freedom integrated out of the total density matrix. Tracing out these degrees of freedom yields a \emph{mixed} density matrix whose time evolution is described by an effective field theory. We show that the coupling leads to profuse fermion pair production for super-Hubble inflaton fluctuations which lead to the \emph{growth of entanglement entropy during inflation}. The power spectrum of inflaton fluctuations features scale invariance violations $\mathcal{P}(k)={\mathcal{P}}_0(k)\exp \{8{\xi }_k\}$ with corrections to the \emph{index and its running directly correlated with the entanglement entropy}: $S_{vN}=-{\sum }_k[\ln (1-{\xi }_k)+\frac{{\xi }_k\ln ({\xi }_k)}{1-{\xi }_k}]$. For super-Hubble fluctuations we find ${\xi }_k=-\frac{Y^2}{48{\pi }^2}\{2N_T\ln (k/k_f)+{\ln }^2(k/k_f)\}$ with $Y$ the Yukawa coupling, $N_T$ the total number of e-folds during inflation, and $k_f$ a "pivot" scale corresponding to the mode that crosses the Hubble radius at the end of inflation.

    ↳ astro-ph.COgr-qchep-phhep-th+1PRD(2018)·46 citations
23. 23*

    Constraining black hole mimickers with gravitational wave observations

    Nathan K. Johnson-McDaniel🇮🇳 · Arunava Mukherjee🇮🇳 · Rahul Kashyap🇮🇳 · Parameswaran Ajith🇮🇳 · Walter Del Pozzo🇬🇧 · Salvatore Vitale🇺🇸

    LIGO and Virgo have recently observed a number of gravitational wave (GW) signals that are fully consistent with being emitted by binary black holes described by general relativity. However, there are theoretical proposals of exotic objects that can be massive and compact enough to be easily confused with black holes. Nevertheless, these objects differ from black holes in having nonzero tidal deformabilities, which can allow one to distinguish binaries containing such objects from binary black holes using GW observations. Using full Bayesian parameter estimation, we investigate the possibility of constraining the parameter space of such "black hole mimickers" with upcoming GW observations. Employing perfect fluid stars with a polytropic equation of state as a simple model that can encompass a variety of possible black hole mimickers, we show how the observed masses and tidal deformabilities of a binary constrain the equation of state. We also show how such constraints can be used to rule out some simple models of boson stars.

    ↳ gr-qcastro-ph.HEhep-phPRD(2020)·91 citations
24. 24*

    Non-Abelian vortex in lattice gauge theory

    Arata Yamamoto🇯🇵

    We perform the Monte Carlo study of the SU(3) non-Abelian Higgs model. We discuss phase structure and non-Abelian vortices by gauge invariant operators. External magnetic fields induce non-Abelian vortices in the color-flavor locked phase. The spatial distribution of non-Abelian vortices suggests the repulsive vortex-vortex interaction.

    ↳ hep-lathep-phPTEP(2018)·8 citations
25. 25*

    Gravitational Interactions of Finite Thickness Global Topological Defects with Black Holes

    L. Perivolaropoulos🇬🇷

    It is well known that global topological defects induce a repulsive gravitational potential for test particles. 'What is the gravitational potential induced by black holes with a cosmological constant (Schwarzschild-de Sitter (S-dS) metric) on finite thickness global topological defects?'. This is the main question addressed in the present analysis. We also discuss the validity of Derrick's theorem when scalar fields are embedded in non-trivial gravitational backgrounds. In the context of the above question, we consider three global defect configurations: a finite thickness spherical domain wall with a central S-dS black hole, a global string loop with a S-dS black hole in the center and a global monopole near a S-dS black hole. Using an analytical model and numerical simulations of the evolving spherical wall we show that the spherical wall experiences a repelling gravitational potential due to the mass of the central black hole. This potential is further amplified by the presence of a cosmological constant. For initial domain wall radius larger than a critical value, the repulsive potential dominates over the wall tension and the wall expands towards the cosmological horizon of the S-dS metric where it develops ghost instabilities. For smaller initial radius, tension dominates and the wall contracts towards the black hole horizon where it also develops ghost instabilities. We also show, using the same analytical model and energetic arguments that a global monopole is gravitationally attracted by a black hole while a cosmological constant induces a repulsive gravitational potential as in the case of test particles. Finally we show that a global string loop with finite thickness experiences gravitational repulsion due to the cosmological constant which dominates over its tension for a radius larger than a critical radius leading to an expanding rather than contracting loop.

    ↳ gr-qcastro-ph.COhep-phhep-th+1PRD(2018)·13 citations
26. 26*

    Maximum-Entropy Priors with Derived Parameters in a Specified Distribution

    Will Handley🇬🇧 · Marius Millea🇫🇷

    We propose a method for transforming probability distributions so that parameters of interest are forced into a specified distribution. We prove that this approach is the maximum entropy choice, and provide a motivating example applicable to neutrino hierarchy inference.

    ↳ math.STastro-ph.COastro-ph.IMhep-ph+1Entropy(2019)·25 citations
27. 27*

    Rigorous Hamiltonian and Lagrangian analysis of classical and quantum theories with minimal length

    Pasquale Bosso🇨🇦

    GUP is a phenomenological model aimed for a description of a minimal length in quantum and classical systems. However, the analysis of problems in classical physics is usually approached preferring a different formalism than the one used for quantum systems, and vice versa. Potentially, the two approaches can result in inconsistencies. Here, we eliminate such inconsistencies proposing particular meanings and relations between the variables used to describe physical systems, resulting in a precise form of the Legendre transformation. Furthermore, we introduce two different sets of canonical variables and the relative map between them. These two sets allow for a complete and unambiguous description of classical and quantum systems.

    ↳ gr-qchep-phphysics.class-phPRD(2018)·54 citations
28. 28*

    Relativistic Dissipative Fluid Dynamics from Non-Equilibrium Statistical Operator

    Arus Harutyunyan🇩🇪 · Armen Sedrakian🇩🇪 · Dirk H. Rischke🇩🇪

    We present a new derivation of second-order relativistic dissipative fluid dynamics for quantum systems using Zubarev's formalism for the non-equilibrium statistical operator. In particular, we discuss the shear-stress tensor to second order in gradients and argue that the relaxation terms for the dissipative quantities arise from memory effects contained in the statistical operator. We also identify new transport coefficients which describe the relaxation of dissipative processes to second order and express them in terms of equilibrium correlation functions, thus establishing Kubo-type formulae for the second-order transport coefficients.

    ↳ nucl-thhep-phParticles(2018)·19 citations
29. 29*

    Construction of a local barK N-pi Sigma-pi Lambda potential and composition of the Lambda(1405)

    Kenta Miyahara🇯🇵 · Tetsuo Hyodo🇯🇵 · Wolfram Weise🇩🇪

    A Kbar N-pi Sigma-pi Lambda coupled-channel potential is constructed on the basis of chiral SU(3) dynamics. Several matching conditions are introduced to formulate an equivalent local potential that reproduces the coupled-channel scattering amplitudes resulting from chiral SU(3)_L times SU(3)_R meson-baryon effective field theory. In contrast to a previously constructed effective single-channel Kbar N potential, the explicit treatment of the pi Sigma channel yields a natural description of the low-mass pole as part of the two-pole structure of the Lambda(1405) resonance. The energy dependence of the potential can now be parametrized with a minimum of polynomial orders. To study the properties of the Lambda(1405) as a quantum-mechanical quasibound state, we derive the normalization condition of its wave function generated by the energy-dependent coupled-channel potential, using the Feshbach projection method. This framework provides an improved understanding of this system from the viewpoint of the compositeness of hadrons. With the properly normalized wave function, we demonstrate and confirm that the high-mass pole of the Lambda(1405) is dominated by the Kbar N component.

    ↳ nucl-thhep-phPRC(2018)·44 citations
30. 30*

    Improving cosmological parameter estimation with the future gravitational-wave standard siren observation from the Einstein Telescope

    Xuan-Neng Zhang🇨🇳 · Ling-Feng Wang🇨🇳 · Jing-Fei Zhang🇨🇳 · Xin Zhang🇨🇳

    Detection of gravitational waves produced by merger of binary compact objects could provide an independent way for measuring the luminosity distance to the gravitational-wave burst source, indicating that gravitational-wave observation, combined with observation of electromagnetic counterparts, can provide "standard sirens" for investigating the expansion history of the universe in cosmology. In this work, we wish to investigate how the future gravitational-wave standard siren observations would break the parameter degeneracies existing in the conventional optical observations and how they help improve the parameter estimation in cosmology. We take the third-generation ground-based gravitational-wave detector, the Einstein Telescope, as an example to make an analysis. By simulating 1000 events data in the redshift range between 0 and 5 based on the ten-year observation of the Einstein Telescope, we find that the gravitational-wave data could largely break the degeneracy between the matter density and the Hubble constant, thus significantly improving the cosmological constraints. We further show that the constraint on the equation-of-state parameter of dark energy could also be significantly improved by including the gravitational-wave data in the cosmological fit.

    ↳ astro-ph.COgr-qchep-phPRD(2019)·77 citations
31. 31*

    Semianalytic Calculation of Gravitational Wave Spectrum Nonlinearly Induced from Primordial Curvature Perturbations

    Kazunori Kohri🇯🇵 · Takahiro Terada🇯🇵

    Whether or not the primordial gravitational wave (GW) produced during inflation is sufficiently strong to be observable, GWs are necessarily produced from the primordial curvature perturbations in the second order of perturbation. The induced GWs can be enhanced by curvature perturbations enhanced at small scales or by the presence of matter-dominated stages of the cosmological history. We analytically calculate the integral in the expression of the power spectrum of the induced GWs which is a universal part independent of the spectrum of the primordial curvature perturbations. This makes the subsequent numerical integrals significantly easy. In simple cases, we derive fully analytic formulas for the induced GW spectrum.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2018)·700 citations
32. 32*

    CMB Spectral Distortions from Cooling Macroscopic Dark Matter

    Saurabh Kumar🇺🇸 · Emanuela Dimastrogiovanni🇺🇸 · Glenn D. Starkman🇺🇸 · Craig Copi🇺🇸 · Bryan Lynn🇺🇸

    We propose a new mechanism by which dark matter (DM) can affect the early universe. The hot interior of a macroscopic DM, or macro, can behave as a heat reservoir so that energetic photons are emitted from its surface. This results in spectral distortions (SDs) of the cosmic microwave background. The SDs depend on the density and the cooling processes of the interior, and the surface composition of the Macros. We use neutron stars as a model for nuclear-density Macros and find that the spectral distortions are mass-independent for fixed density. In our work, we find that, for Macros of this type that constitute 100$\%$ of the dark matter, the $\mu$ and $y$ distortions can be above detection threshold for typical proposed next-generation experiments such as PIXIE.

    ↳ astro-ph.COastro-ph.GAhep-phPRD(2019)·8 citations
33. 33*

    The Infrared Structure of Nambu-Goldstone Bosons

    Ian Low🇺🇸 · Zhewei Yin🇺🇸

    The construction of effective actions for Nambu-Goldstone bosons, and the nonlinear sigma model, usually requires a target coset space $G/H$. Recent progresses uncovered a new formulation using only IR data, without reference to $G/H$, by imposing the Adler's zero condition, which can be seen to originate from the superselection rule in the space of degenerate vacua. The IR construction imposes a nonlinear shift symmetry on the Lagrangian to enforce the correct single soft limit amid constraints of the unbroken group $H$. We present a systematic study on the consequence of the Adler's zero condition in correlators of nonlinear sigma model, by deriving the conserved current and the Ward identity associated with the nonlinear shift symmetry, and demonstrate how the old-fashioned current algebra emerges. The Ward identity leads to a new representation of on-shell amplitudes, which amounts to bootstrapping the higher point amplitudes from lower point amplitudes and adding new vertices to satisfy the Adler's condition. The IR perspective allows one to extract Feynman rules for the mysterious extended theory of biadjoint cubic scalars residing in the subleading single soft limit, which was first discovered using the Cachazo-He-Yuan representation of scattering amplitudes. In addition, we present the subleading triple soft theorem in the nonlinear sigma model and show that it is also controlled by on-shell amplitudes of the same extended theory as in the subleading single soft limit.

    ↳ hep-thhep-phJHEP(2018)·47 citations
34. 34*

    X-Ray Properties of AGN in Brightest Cluster Galaxies. I.A Systematic Study of the Chandra Archive in the $0.2<z<0.3$ and $0.55<z<0.75$ Redshift Range

    Lilan Yang · Paolo Tozzi · Heng Yu🇺🇸 · Elisabeta Lusso · Massimo Gaspari · Roberto Gilli · Emanuele Nardini · Guido Risaliti

    We present a search for nuclear X-ray emission in the brightest cluster galaxies (BCGs) of a sample of groups and clusters of galaxies extracted from the Chandra archive. The exquisite angular resolution of Chandra allows us to obtain robust photometry at the position of the BCG, and to firmly identify unresolved X-ray emission when present, thanks to an accurate characterization of the extended emission at the BCG position. We consider two redshift bins (0.2<z<0.3 and 0.55<z<0.75) and analyze all the clusters observed by Chandra with exposure time larger than 20 ks. Our samples have 81 BCGs in 73 clusters and 51 BCGs in 49 clusters in the low- and high-redshift bin, respectively. X-ray emission in the soft (0.5-2 keV) or hard (2-7 keV) band is detected only in 14 and 9 BCGs ($\sim 18$% of the total samples), respectively. The X-ray photometry shows that at least half of the BCGs have a high hardness ratio, compatible with significant intrinsic absorption. This is confirmed by the spectral analysis with a power law model plus intrinsic absorption. We compute the fraction of X-ray bright BCGs above a given hard X-ray luminosity, considering only sources with positive photometry in the hard band (12/5 sources in the low/high-z sample). In the 0.2<z<0.3 interval the hard X-ray luminosity ranges from $10^{42}$ to $7\times 10^{43}$ erg s${}^{-1}$, with most sources found below $10^{43}$ erg s${}^{-1}$. In the $0.55<z<0.75$ range, we find a similar distribution of luminosities below $\sim 10^{44}$ erg s${}^{-1}$, plus two very bright sources of a few $10^{45}$ erg s${}^{-1}$ associated with two radio galaxies. We also find that X-ray luminous BCGs tend to be hosted by cool-core clusters, despite the majority of cool cores do not host nuclear X-ray emission (Abridged).

    ↳ astro-ph.GAhep-phApJ(2018)·13 citations
35. 35*

    Primordial Black Hole Formation During Slow Reheating After Inflation

    Bernard Carr🇬🇧 · Konstantinos Dimopoulos🇬🇧 · Charlotte Owen🇬🇧 · Tommi Tenkanen🇬🇧

    We study the formation of primordial black holes (PBHs) in the early Universe during a period of slow reheating after inflation. We demonstrate how the PBH formation mechanism may change even before the end of the matter-dominated phase and calculate the expected PBH mass function. We find that there is a threshold for the variance of the density contrast, ${\sigma }_c\simeq 0.05$, below which the transition occurs even before reheating, with this having important consequences for the PBH mass function. We also show that there is a maximum cut-off for the PBH mass at around $100M_{\odot }$, below which the subdominant radiation bath affects PBH production, making the scenario particularly interesting for the recent LIGO observations of black hole mergers.

    ↳ astro-ph.COhep-phhep-thPRD(2018)·70 citations
36. 36*

    Standard Model Fermions and Infinite-Dimensional R-Symmetries

    Krzysztof A. Meissner🇵🇱 · Hermann Nicolai🇩🇪

    Following up on our earlier work where we showed how to amend a scheme originally proposed by M. Gell-Mann to identify the 48 spin 1/2 fermions of N=8 supergravity that remain after complete breaking of N=8 supersymmetry with the 3x16 quarks and leptons of the Standard Model, we further generalize the construction to account for the full SU(3)_c x SU(2)_w x U(1)_Y assignments, with an additional family symmetry SU(3)_f. Our proposal relies in an essential way on embedding the SU(8) R-symmetry of N=8 supergravity into the (infinite-dimensional) `maximal compact' subgroup K(E10) of the conjectured maximal duality symmetry E10. As a by-product, it predicts fractionally charged and possibly strongly interacting massive gravitinos. It also indicates how E10 and K(E10) can supersede supersymmetry as a guiding principle for unification.

    ↳ hep-thhep-phPRL(2018)·26 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.