Tue·Jan 24, 2017Tuesday·January 24, 2017

1. 01*

   $U(1)\otimes BRST$ symmetry, of on-shell T-matrix elements and (1-$\varphi$-I) Green's functions, determines the vacuum state of the Abelian Higgs Model from symmetry alone: minimization of the scalar-sector effective potential is unnecessary

   Özenç Güngör🇺🇸 · Bryan W. Lynn🇺🇸 · Glenn D. Starkman🇺🇸

   The weak-scale $U(1{)}_Y$ Abelian Higgs Model (AHM) is the spontaneous-symmetry-breaking gauge theory of a complex scalar $\varphi =\frac{1}{\sqrt{2}}(H+i\pi )$ and a vector $A_{\mu }$. Global $U(1{)}_Y\otimes BRST$ symmetry emerges: when it is realized that on-shell T-matrix elements enjoy an extra $U(1{)}_Y$ global symmetry beyond the Lagragian's BRST symmetry. The symmetries co-exist: $U(1{)}_Y$ generators ${\delta }_{U(1{)}_Y}$ commute with BRST generators s and $[{\delta }_{U(1{)}_Y},s]\mathcal{L}=0$. Two towers of Ward Takahashi identities (WTI), which include all-loop-orders quantum corrections, emerge: a tower of relations among off-shell 1-$\varphi$-I (but 1-$A_{\mu }$-Reducible) Green's functions; another tower of Adler-zero WTI for on-shell T-matrix elements. The T-matrix's LSS theorem forces tadpoles to automatically vanish (equivalently $m_{\pi }^2=0$) by symmetry alone. We show that, when the full symmetries of Lorenz gauge AHM are enforced on the scalar-sector effective potential, the vacuum state of the theory is specified/decided by symmetry alone. We use recursive WTI relations among Green's functions to include opeators of dimension $\ge 1$. We express the fully renormalized scalar-sector effective potential in a form which shows explicitly that, for small scalar field values, the gauge-independent vacuum state of the theory $⟨H{⟩}_{renormalized}=Z_{\varphi }^{1/2}⟨H{⟩}_{bare}$ is determined by $U(1{)}_Y\otimes BRST$ symmetry alone, without minimizing the effective potential.

   hep-phhep-th3 citations
2. 02*

   Study on the reaction of $\gamma p\to f_1(1285)p$ in Regge-effective Lagrangian approach

   Yan-Yan Wang🇨🇳 · Li-Juan Liu🇨🇳 · En Wang🇨🇳 · De-Min Li🇨🇳

   The production of the $f_1(1285)$ resonance in the reaction of $\gamma p\to f_1(1285)p$ is investigated within a Regge-effective Lagrangian approach. Besides the contributions of the $t$-channel $\rho$ and $\omega$ trajectories exchanges, we also take into account the contributions of $s/u$-channel $N(2300)$ terms, $s/u$-channel nucleon terms, and the contact term. By fitting to the CLAS data, we find that the $s$-channel $N(2300)$ term plays an important role in this reaction. We predict the total cross section for this reaction, and find a clear bump structure around $W=2.3$ GeV, which is associated with the $N(2300)$ state. The reaction of $\gamma p\to f_1(1285)p$ could be useful to further study of the $N(2300)$ experimentally.

   hep-phhep-exPRD(2017)·15 citations
3. 03*

   Relativistic five-quark equations and the strange (S = - 3) pentaquarks

   S.M. Gerasyuta🇷🇺 · V.I. Kochkin🇷🇺

   The relativistic five-quark equations are found in the framework of the dispersion relation technique. The solutions of these equations using the method based on the extraction of the leading singularities of the amplitudes are obtained. The five-quark amplitudes for the S = -3 strange pentaquarks including the u, d, s quarks determine the masses of strange pentaquarks. The mass spectra of the strange pentaquarks with JP=1/2, 3/2 are calculated.

   hep-ph0 citations
4. 04*

   Parton energy loss in QCD matter

   Konrad Tywoniuk🇨🇭

   QCD jets, produced copiously in heavy-ion collisions at LHC and also at RHIC, serve as probes of the dynamics of the quark-gluon plasma (QGP). Jet fragmentation in the medium is interesting in its own right and, in order to extract pertinent information about the QGP, it has to be well understood. We present a brief overview of the physics involved and argue that jet substructure observables provide new opportunities for understanding the nature of the modifications.

   hep-phnucl-thNucl.Part.Phys.Proc.(2017)·1 citation
5. 05*

   Di-higgs enhancement by neutral scalar as probe of new colored sector

   Koji Nakamura🇯🇵 · Kenji Nishiwaki🇰🇷 · Kin-ya Oda🇯🇵 · Seong Chan Park🇰🇷 · Yasuhiro Yamamoto🇰🇷

   We study a class of models in which the Higgs pair production is enhanced at hadron colliders by an extra neutral scalar. The scalar particle is produced by the gluon fusion via a loop of new colored particles, and decays into di-Higgs through its mixing with the Standard Model Higgs. Such a colored particle can be the top/bottom partner, such as in the dilaton model, or a colored scalar which can be triplet, sextet, octet, etc., called leptoquark, diquark, coloron, etc., respectively. We examine the experimental constraints from the latest Large Hadron Collider (LHC) data, and discuss the future prospects of the LHC and the Future Circular Collider up to 100TeV. We also point out that the 2.4$\sigma$ excess in the $b\bar{b}\gamma \gamma$ final state reported by the ATLAS experiment can be interpreted as the resonance of the neutral scalar at 300GeV.

   hep-phEPJC(2017)·32 citations
6. 06*

   Entropic destruction of heavy quarkonium from a deformed $Ad{S}_5$ model

   Zi-qiang Zhang🇨🇳 · Zhong-jie Luo🇨🇳 · De-fu Hou🇨🇳 · Gang Chen🇨🇳

   In this paper, we study the destruction of heavy quarkonium due to the entropic force in a deformed $Ad{S}_5$ model. The effects of the deformation parameter on the inter-distance and the entropic force are investigated. The influence of the deformation parameter on the quarkonium dissociation is analyzed. It is shown that the inter-distance increases in the presence of the deformation parameter. In addition, the deformation parameter has the effect of decreasing the entropic force. This results imply that the quarkonium dissociates harder in a deformed AdS background than that in an usual AdS background, in agreement with earlier findings.

   hep-phAdv.High Energy Phys.(2017)·8 citations
7. 07*

   Flavon VEV Scales in U(3)$\times$U(3)${}^{\prime }$ Model

   Yoshio Koide🇯🇵 · Hiroyuki Nishiura🇯🇵

   We have already proposed a quark and lepton mass matrix model based on U(3)$\times$U(3)${}^{\prime }$ family symmetry as the so-called Yukawaon model, in which the U(3) symmetry is broken by VEVs of flavons $({\Phi }_f{)}_i^{\alpha }$ which are $(3,3^{\ast })$ of U(3)$\times$U(3)${}^{\prime }$. The model has successfully provided the unified description of quark and lepton masses and mixings by using the observed charged lepton masses as only family-number dependent input parameters. Our next concern is scales of VEVs of the flavons. In the present paper, we estimate the magnitudes of the VEV scales of flavons of the model which is newly reconstructed without changing the previous phenomenological success of parameter fitting for masses and mixings of quarks and leptons. We estimate that VEVs of flavons with $(8+1,1)$, $(3,3^{\ast })$, and $(1,8+1)$ are of 25the orders of $10$ TeV, $10^4$ TeV, and $10^7$ TeV, respectively.

   hep-phInt.J.Mod.Phys.A(2017)·4 citations
8. 08*

   Higgs boson pair productions in the Georgi-Machacek model at the LHC

   Jung Chang🇹🇼 · Chuan-Ren Chen🇹🇼 · Cheng-Wei Chiang🇹🇼

   Higgs bosons pair production is well known for its sensitivity to probing the sign and size of Higgs boson self coupling, providing a way to determine whether there is an extended Higgs sector. The Georgi-Machacek (GM) model extends the Standard Model (SM) with an $SU(2{)}_L$ triplet scalar field that has one real and one complex components. The Higgs self coupling now has a wider range than that in the SM, with even the possibility of a sign flip. The new heavy singlet Higgs boson $H_1^0$ can contribute to s-channel production of the $hh$ pairs. In this work, we study non-resonant/resonant Higgs boson pair productions $pp\to hh$ and $pp\to H_1^0\to hh$, focusing exclusively on the contribution of $H_1^0$. We show the sensitivity for Higgs boson pair production searches at the 13-TeV LHC with the luminosities of $3.2,30$ and $100$~fb${}^{-1}$.

   hep-phJHEP(2017)·41 citations
9. 09*

   An Alternative Method of Determining the Neutrino Mass Ordering in Reactor Neutrino Experiments

   S.M. Bilenky🇷🇺 · F. Capozzi🇮🇹 · S.T. Petcov🇮🇹

   We discuss a novel alternative method of determining the neutrino mass ordering in medium baseline experiments with reactor anti-neutrinos. Results on the potential sensitivity of the new method are also presented.

   hep-phPLB(2017)·12 citations
10. 10*

    The Higgs boson decay into ZZ decaying to identical fermion pairs

    Taras V. Zagoskin🇺🇦 · Alexander Yu. Korchin🇺🇦

    In order to investigate various decay channels of the Higgs boson $h$ or the hypothetical dilaton, we consider a neutral particle $X$ with zero spin and arbitrary $CP$ parity. This particle can decay into two off-mass-shell $Z$ bosons ($Z_1^{\ast }$ and $Z_2^{\ast }$) decaying to identical fermion-antifermion pairs ($f\bar{f}$): $X\to Z_1^{\ast }{Z}_2^{\ast }\to f\bar{f}f\bar{f}$. We derive analytical formulas for the fully differential width of this decay and for the fully differential width of $h\to Z_1^{\ast }{Z}_2^{\ast }\to 4\ell$ ($4\ell$ stands for $4e$, $4\mu$, or $2e2\mu$). Integration of these formulas yields some Standard Model histogram distributions of the decay $h\to Z_1^{\ast }{Z}_2^{\ast }\to 4\ell$, which are compared with corresponding Monte Carlo simulated distributions obtained by ATLAS and with ATLAS experimental data.

    hep-phInt.J.Mod.Phys.A(2017)·2 citations
11. 11*

    Rare radiative charm decays within the standard model and beyond

    Stefan de Boer🇩🇪 · Gudrun Hiller🇩🇪

    We present standard model (SM) estimates for exclusive $c\to u\gamma$ processes in heavy quark and hybrid frameworks. Measured branching ratios $\mathcal{B}(D^0\to (\varphi ,{\bar{K}}^{\ast 0})\gamma )$ are at or somewhat exceeding the upper range of the SM and suggest slow convergence of the $1/m_D,{\alpha }_s$-expansion. Model-independent constraints on $|\Delta C|=|\Delta U|=1$ dipole operators from $\mathcal{B}(D^0\to {\rho }^0\gamma )$ data are obtained. Predictions and implications for leptoquark models are worked out. While branching ratios are SM-like CP asymmetries $\lesssim 10\%$ can be induced. In SUSY deviations from the SM can be even larger with CP asymmetries of $O(0.1)$. If ${\Lambda }_c$-baryons are produced polarized, such as at the $Z$-pole, an angular asymmetry in ${\Lambda }_c\to p\gamma$ decays can be studied that is sensitive to chirality-flipped contributions.

    hep-phhep-exJHEP(2017)·63 citations
12. 12*

    Temperature oscillations and sound waves in hadronic matter

    Grzegorz Wilk🇵🇱 · Zbigniew Wlodarczyk🇵🇱

    Recent high energy CERN LHC experiments on transverse momenta distributions of produced particles seem to show the existence of some (small but persistent) log-periodic oscillation in the ratios $R={\sigma }_{data}\left(p_T\right)/{\sigma }_{fit}\left(p_T\right)$. We argue that they can provide us with so far unnoticed information on the production process, which can be interpreted as the presence of some kind of sound waves formed during the collision process in the bulk of the produced high density matter.

    hep-phcond-mat.stat-mechnucl-thPhysica A(2017)·8 citations
13. 13*

    Scheming in the SMEFT... and a reparameterization invariance!

    Ilaria Brivio🇩🇰 · Michael Trott🇩🇰

    We explain a reparameterization invariance in the Standard Model Effective Field Theory present when considering $\bar{\psi }\psi \to \bar{\psi }\psi$ scatterings (with $\psi$ a fermion) and how this leads to unconstrained combinations of Wilson coefficients in global data analyses restricted to these measurements. We develop a $\{{\hat{m}}_W,{\hat{m}}_Z,{\hat{G}}_F\}$ input parameter scheme and compare results to the case when an input parameter set $\{\hat{\alpha },{\hat{m}}_Z,{\hat{G}}_F\}$ is used to constrain this effective theory from the global data set, confirming the input parameter independence of the unconstrained combinations of Wilson coefficients, and supporting the reparameterization invariance explanation. We discuss some conceptual issues related to these degeneracies that are relevant for LHC data reporting and analysis.

    hep-phJHEP(2017)·93 citations
14. 14*

    Rescattering effects in the hadronic-light-by-light contribution to the anomalous magnetic moment of the muon

    Gilberto Colangelo🇨🇭 · Martin Hoferichter🇺🇸 · Massimiliano Procura🇨🇭 · Peter Stoffer🇺🇸

    We present a first model-independent calculation of $\pi \pi$ intermediate states in the hadronic-light-by-light (HLbL) contribution to the anomalous magnetic moment of the muon $(g-2{)}_{\mu }$ that goes beyond the scalar QED pion loop. To this end we combine a recently developed dispersive description of the HLbL tensor with a partial-wave expansion and demonstrate that the known scalar-QED result is recovered after partial-wave resummation. Using dispersive fits to high-statistics data for the pion vector form factor, we provide an evaluation of the full pion box, $a_{\mu }^{\pi \text{-box}}=-15.9(2)\times 10^{-11}$. We then construct suitable input for the ${\gamma }^{\ast }{\gamma }^{\ast }\to \pi \pi$ helicity partial waves based on a pion-pole left-hand cut and show that for the dominant charged-pion contribution this representation is consistent with the two-loop chiral prediction and the COMPASS measurement for the pion polarizability. This allows us to reliably estimate $S$-wave rescattering effects to the full pion box and leads to our final estimate for the sum of these two contributions: $a_{\mu }^{\pi \text{-box}}+a_{\mu ,J=0}^{\pi \pi ,\pi \text{-pole LHC}}=-24(1)\times 10^{-11}$.

    hep-phhep-exhep-latnucl-thPRL(2017)·193 citations
15. 15*

    Magnetic Bubble Chambers and Sub-GeV Dark Matter Direct Detection

    Philip C. Bunting🇺🇸 · Giorgio Gratta🇺🇸 · Tom Melia🇺🇸 · Surjeet Rajendran🇺🇸

    We propose a new application of single molecule magnet crystals: their use as "magnetic bubble chambers" for the direct detection of sub-GeV dark matter. The spins in these macroscopic crystals effectively act as independent nano-scale magnets. When anti-aligned with an external magnetic field they form meta-stable states with a relaxation time that can be very long at sufficiently low temperatures. The Zeeman energy stored in this system can be released through localized heating, caused for example by the scattering or absorption of dark matter, resulting in a spin avalanche (or "magnetic deflagration") that amplifies the effects of the initial heat deposit, enabling detection. Much like the temperature and pressure in a conventional bubble chamber, the temperature and external magnetic field set the detection threshold for a single molecule magnet crystal. We discuss this detector concept for dark matter detection and propose ways to ameliorate backgrounds. If successfully developed, this detector concept can search for hidden photon dark matter in the meV - eV mass range with sensitivities exceeding current bounds by several orders of magnitude.

    hep-phastro-ph.COhep-exphysics.chem-ph+1PRD(2017)·76 citations
16. 16*

    A Minimal Model of Gravitino Dark Matter

    Karim Benakli🇫🇷 · Yifan Chen🇫🇷 · Emilian Dudas🇫🇷 · Yann Mambrini🇫🇷

    Motivated by the absence of signals of new physics in both searches for new particles at LHC and for a Weakly Interacting Massive Particle (WIMP) dark matter candidate, we consider a scenario where supersymmetry is broken at a scale above the reheating temperature. The low energy particle content consists then only in Standard Model states and a gravitino. We investigate the possibility that the latter provides the main component of dark matter through a freeze in mechanism from annihilation of thermalized Standard Model particles. We focus on the case where its production through scattering in the thermal plasma is well approximated by the non-linear supersymmetric effective Lagrangian of the associated goldstino and identify the parameter space allowed by the cosmological constraints, allowing the possibility of large reheating temperature compatible with leptogenesis scenarios, alleviating the so called "gravitino problem".

    hep-phastro-ph.HEhep-thPRD(2017)·82 citations
17. 17*

    Numerical Multi-Loop Calculations via Finite Integrals and One-Mass EW-QCD Drell-Yan Master Integrals

    Andreas von Manteuffel🇺🇸 · Robert M. Schabinger🇮🇪

    We study a recently-proposed approach to the numerical evaluation of multi-loop Feynman integrals using available sector decomposition programs. As our main example, we consider the two-loop integrals for the $\alpha {\alpha }_s$ corrections to Drell-Yan lepton production with up to one massive vector boson in physical kinematics. As a reference, we evaluate these planar and non-planar integrals by the method of differential equations through to weight five. Choosing a basis of finite integrals for the numerical evaluation with SecDec3 leads to tremendous performance improvements and renders the otherwise problematic seven-line topologies numerically accessible. As another example, basis integrals for massless QCD three loop form factors are evaluated with FIESTA4. Here, employing a basis of finite integrals results in an overall speedup of more than an order of magnitude.

    hep-phhep-thJHEP(2017)·45 citations
18. 18*

    Lectures on Flavor Physics and CP Violation

    Benjamín Grinstein🇺🇸

    Two short introductory lectures on Flavor Physics delivered at CLASHEP 2015. Among included topics: The KM matrix and the KM model of CP-violation, Determination of KM Elements, FCNC and GIM, New Physics and Flavor, Neutral Meson Mixing and CP Asymmetries. Many problems for the student, and solutions to selected problems, included.

    hep-ph8 citations
19. 19*

    D-Meson Mixing in 2+1-Flavor Lattice QCD

    Chia Cheng Chang🇺🇸 · C.M. Bouchard🇺🇸 · A.X. El-Khadra🇺🇸 · E. Freeland🇺🇸 · E. Gámiz🇪🇸 · A.S. Kronfeld🇺🇸 · J.W. Laiho🇺🇸 · E.T. Neil🇺🇸 · J.N. Simone🇺🇸 · R.S. Van de Water🇺🇸

    We present results for neutral D-meson mixing in 2+1-flavor lattice QCD. We compute the matrix elements for all five operators that contribute to D mixing at short distances, including those that only arise beyond the Standard Model. Our results have an uncertainty similar to those of the ETM collaboration (with 2 and with 2+1+1 flavors). This work shares many features with a recent publication on B mixing and with ongoing work on heavy-light decay constants from the Fermilab Lattice and MILC Collaborations.

    ↳ hep-lathep-phPoS(2017)·2 citations
20. 20*

    Higher-Order Scheme-Independent Calculations of Physical Quantities in the Conformal Phase of a Gauge Theory

    Thomas A. Ryttov🇩🇰 · Robert Shrock🇺🇸

    We consider an asymptotically free vectorial SU($N_c$) gauge theory with $N_f$ massless fermions in a representation $R$, having an infrared fixed point (IRFP) of the renormalization group at ${\alpha }_{IR}$ in the conformal non-Abelian Coulomb phase. The cases with $R$ equal to the fundamental, adjoint, and symmetric rank-2 tensor representation are considered. We present scheme-independent calculations of the anomalous dimension ${\gamma }_{\bar{\psi }\psi ,IR}$ to $O({\Delta }_f^4)$ and ${\beta }_{IR}^{\prime }$ to $O({\Delta }_f^5)$ at this IRFP, where ${\Delta }_f$ is an $N_f$-dependent expansion parameter. Comparisons are made with conventional $n$-loop calculations and lattice measurements. As a test of the accuracy of the ${\Delta }_f$ expansion, we calculate ${\gamma }_{\bar{\psi }\psi ,IR}$ to $O({\Delta }_f^3)$ in $\mathcal{N}=1$ SU($N_c$) supersymmetric quantum chromodynamics and find complete agreement, to this order, with the exactly known expression. The ${\Delta }_f$ expansion also avoids a problem in which an IRFP may not be manifest as an IR zero of a higher $n$-loop beta function.

    ↳ hep-thhep-lathep-phPRD(2017)·26 citations
21. 21*

    Hořava Gravity at a Lifshitz Point: A Progress Report

    Anzhong Wang🇨🇳

    Hořava gravity at a Lifshitz point is a theory intended to quantize gravity by using techniques of traditional quantum field theories. To avoid Ostrogradsky's ghosts, a problem that has been plaguing quantization of general relativity since the middle of 1970's, Hořava chose to break the Lorentz invariance by a Lifshitz-type of anisotropic scaling between space and time at the ultra-high energy, while recovering (approximately) the invariance at low energies. With the stringent observational constraints and self-consistency, it turns out that this is not an easy task, and various modifications have been proposed, since the first incarnation of the theory in 2009. In this review, we shall provide a progress report on the recent developments of Hořava gravity. In particular, we first present four most-studied versions of Hořava gravity, by focusing first on their self-consistency and then their consistency with experiments, including the solar system tests and cosmological observations. Then, we provide a general review on the recent developments of the theory in three different but also related areas: (i) universal horizons, black holes and their thermodynamics; (ii) non-relativistic gauge/gravity duality; and (iii) quantization of the theory. The studies in these areas can be generalized to other gravitational theories with broken Lorentz invariance.

    ↳ gr-qcastro-ph.COhep-phhep-thInt.J.Mod.Phys.D(2017)·217 citations
22. 22*

    Propagation of cosmic rays in the AMS-02 era

    Qiang Yuan (PMO)🇨🇳 · Su-Jie Lin (IHEP)🇨🇳 · Kun Fang (IHEP)🇨🇳 · Xiao-Jun Bi (IHEP)🇨🇳

    In this work we use the newly reported Boron-to-Carbon ratio (B/C) from AMS-02 and the time-dependent proton fluxes from PAMELA and AMS-02 to constrain the source and propagation parameters of cosmic rays in the Milky Way. A linear correlation of the solar modulation parameter with solar activities is assumed to account for the time-varying cosmic ray fluxes. A comprehensive set of propagation models, with/without reacceleration or convection, have been discussed and compared. We find that only the models with reacceleration can self-consistently fit both the proton and B/C data. The rigidity dependence slope of the diffusion coefficient, $\delta$, is found to be about $0.38-0.50$ for the diffusion-reacceleration models. The plain diffusion and diffusion-convection models fit the data poorly. We compare different model predictions of the positron and antiproton fluxes with the data. We find that the diffusion-reacceleration models over-produce low energy positrons, while non-reacceleration models give better fit to the data. As for antiprotons, reacceleration models tend to under-predict low energy antiproton fluxes, unless a phenomenological modification of the velocity-dependence of the diffusion coefficient is applied. Our results suggest that there could be important differences of the propagation for nuclei and leptons, in either the Milky Way or the solar heliosphere.

    ↳ astro-ph.HEhep-phPRD(2017)·129 citations
23. 23*

    Manybody aspects of gravity in compact stars

    Mofazzal Azam · Jitesh R. Bhatt🇮🇳 · M. Sami🇮🇳

    Compact stars such as neutron stars and black holes are gravitationally bound many body systems. We investigate the importance of short and long range part of gravity for such systems. From our analysis, we conclude that the true essence of gravity lies with the long range nature of the interaction. At the end we show how these arguments in the manybody theory consistently leads to Dvali-Gomez picture of a black holes as a collective bound state of long wavelength gravitons.

    ↳ gr-qcastro-ph.HEhep-phhep-thPhys.Scripta(2018)·3 citations
24. 24*

    A model for pion-pion scattering in large-N QCD

    Gabriele Veneziano🇫🇷 · Shimon Yankielowicz🇮🇱 · Enrico Onofri🇮🇹

    Following up on recent work by Caron-Huot et al. we consider a generalization of the old Lovelace-Shapiro model as a toy model for Pi-Pi scattering satisfying (most of) the properties expected to hold in ('t Hooft's) large-N limit of massless QCD. In particular, the model has asymptotically linear and parallel Regge trajectories at positive t, a positive leading Regge intercept ${\alpha }_0<1$, and an effective bending of the trajectories in the negative-t region producing a fixed branch point at J=0 for $t<t_0<0$. Fixed (physical) angle scattering can be tuned to match the power-like (including logarithmic corrections) behavior predicted by perturbative QCD: $A(s,t)s^{-\beta }\log (s{)}^{-\gamma }F(\theta )$. Tree-level unitarity (i.e. positivity of residues for all values of s and J) imposes strong constraints on the allowed region in the alpha_0-beta-gamma parameter space, which nicely includes a physically interesting region around ${\alpha }_0=0.5$, $\beta =2$ and $\gamma =3$. The full consistency of the model would require an extension to multi-pion processes, a program we do not undertake in this paper.

    ↳ hep-thhep-phJHEP(2017)·25 citations
25. 25*

    Quark matter with strong magnetic field and possibility of the third family of compact stars

    Hajime Sotani🇯🇵 · Toshitaka Tatsumi🇯🇵

    We consider the possibility for the existence of the third family of compact objects, considering the effect of strong magnetic fields inside the hybrid stars. As a result, we demonstrate such new sequences of stable equilibrium configurations for some hadronic equations of state. Through the analysis of the adiabatic index inside stars, we find the conditions for appearing the third family of compact objects, i.e., for hadronic stars without quarks, that the maximum mass should be small, the central density for the maximum mass should be also small, and the radius for the the maximum mass should be large. Even for soft hadronic equations of state, the two solar-mass stars might survive as the third family of compact objects, once quark matter with strong magnetic field, such as $\sim \mathcal{O}(10^{19}\mathrm{G})$, is taken into account. It might give a hint to solve the so-called hyperon puzzle in nuclear physics.

    ↳ astro-ph.HEhep-phnucl-thMNRAS(2017)·12 citations
26. 26*

    The stochastic spectator

    Robert J. Hardwick🇬🇧 · Vincent Vennin🇬🇧 · Christian T. Byrnes🇬🇧 · Jesús Torrado🇬🇧 · David Wands🇬🇧

    We study the stochastic distribution of spectator fields predicted in different slow-roll inflation backgrounds. Spectator fields have a negligible energy density during inflation but may play an important dynamical role later, even giving rise to primordial density perturbations within our observational horizon today. During de-Sitter expansion there is an equilibrium solution for the spectator field which is often used to estimate the stochastic distribution during slow-roll inflation. However slow roll only requires that the Hubble rate varies slowly compared to the Hubble time, while the time taken for the stochastic distribution to evolve to the de-Sitter equilibrium solution can be much longer than a Hubble time. We study both chaotic (monomial) and plateau inflaton potentials, with quadratic, quartic and axionic spectator fields. We give an adiabaticity condition for the spectator field distribution to relax to the de-Sitter equilibrium, and find that the de-Sitter approximation is never a reliable estimate for the typical distribution at the end of inflation for a quadratic spectator during monomial inflation. The existence of an adiabatic regime at early times can erase the dependence on initial conditions of the final distribution of field values. In these cases, spectator fields acquire sub-Planckian expectation values. Otherwise spectator fields may acquire much larger field displacements than suggested by the de-Sitter equilibrium solution. We quantify the information about initial conditions that can be obtained from the final field distribution. Our results may have important consequences for the viability of spectator models for the origin of structure, such as the simplest curvaton models.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2017)·91 citations
27. 27*

    A Combinatoric Shortcut to Evaluate CHY-forms

    Gang Chen🇨🇳 · Yeuk-Kwan E. Cheung🇨🇳 · Tianheng Wang🇨🇳 · Feng Xu🇨🇳

    In \cite{Chen:2016fgi} we proposed a differential operator for the evaluation of the multi-dimensional residues on isolated (zero-dimensional) poles.In this paper we discuss some new insight on evaluating the (generalized) Cachazo-He-Yuan (CHY) forms of the scattering amplitudes using this differential operator. We introduce a tableau representation for the coefficients appearing in the proposed differential operator. Combining the tableaux with the polynomial forms of the scattering equations, the evaluation of the generalized CHY form becomes a simple combinatoric problem. It is thus possible to obtain the coefficients arising in the differential operator in a straightforward way. We present the procedure for a complete solution of the $n$-gon amplitudes at one-loop level in a generalized CHY form. We also apply our method to fully evaluate the one-loop five-point amplitude in the maximally supersymmetric Yang-Mills theory; the final result is identical to the one obtained by Q-Cut.

    ↳ hep-thhep-phmath-phmath.MPJHEP(2017)·12 citations
28. 28*

    Equations of state for real gases on the nuclear scale

    Volodymyr Vovchenko🇩🇪

    The formalism to augment the classical models of equation of state for real gases with the quantum statistical effects is presented. It allows an arbitrary excluded volume procedure to model repulsive interactions, and an arbitrary density-dependent mean field to model attractive interactions. Variations on the excluded volume mechanism include van der Waals (VDW) and Carnahan-Starling models, while the mean fields are based on VDW, Redlich-Kwong-Soave, Peng-Robinson, and Clausius equations of state. The VDW parameters of the nucleon-nucleon interaction are fitted in each model to the properties of the ground state of nuclear matter, and the following range of values is obtained: $a=330-430$ MeV fm${}^3$ and $b=2.5-4.4$ fm${}^3$. In the context of the excluded-volume approach, the fits to the nuclear ground state disfavor the values of the effective hard-core radius of a nucleon significantly smaller than $0.5$ fm, at least for the nuclear matter region of the phase diagram. Modifications to the standard VDW repulsion and attraction terms allow to improve significantly the value of the nuclear incompressibility factor $K_0$, bringing it closer to empirical estimates. The generalization to include the baryon-baryon interactions into the hadron resonance gas model is performed. The behavior of the baryon-related lattice QCD observables at zero chemical potential is shown to be strongly correlated to the nuclear matter properties: an improved description of the nuclear incompressibility also yields an improved description of the lattice data at $\mu =0$.

    ↳ nucl-thcond-mat.quant-gascond-mat.stat-mechhep-phPRC(2017)·57 citations
29. 29*

    Top physics beyond the LHC

    Marcel Vos🇪🇸

    Several proposals exist for energy-frontier facilities after the HL-LHC. In this contribution I review the potential of these facilities to perform key measurements of top quark properties and interacions. Top quark precision physics at a lepton collider provides excellent opportunities for the determination of the top quark mass and its couplings to neutral electro-weak gauge bosons. Measurements at very high center-of-mass energy at a new hadron collider likely offer the ultimate precision on the QCD interaction of the top quark and its coupling to the Higgs boson. The combination of a lepton and a hadron collider can improve the precision of all these measurements by two orders of magnitude with respect to the current state-of-the-art and by an order of magnitude compared to the precision envisaged after 3/ab at the LHC.

    ↳ hep-exhep-ph7 citations
30. 30*

    Some New Possible Anticipated Signals for Existence of Magnetic Monopoles

    Qiu-He Peng🇨🇳 · Jing-Jing Liu🇨🇳 · Zhong-Qi Ma🇨🇳

    We summarize some predictions from the model of supermassive object with magnetic monopoles which match up with recent astronomical observations quantitatively. They may be the signals for existence of magnetic monopoles in the supermassive objects, such as one at the Galactic Center.

    ↳ astro-ph.HEhep-phhep-thNew Astron.(2017)·7 citations
31. 31*

    Fast neutrino conversions: Ubiquitous in compact binary merger remnants

    Meng-Ru Wu🇩🇰 · Irene Tamborra🇩🇰

    The massive neutron star (NS) or black hole (BH) accretion disk resulting from NS--NS or NS--BH mergers is dense in neutrinos. We present the first study on the role of angular distributions in the neutrino flavor conversion above the remnant disk. In particular, we focus on "fast" pairwise conversions whose rate depends on the local angular intensity of the electron lepton number carried by neutrinos. Because of the emission geometry and the flux density of ${\bar{\nu }}_e$ being larger than that of ${\nu }_e$, fast conversions prove to be a generic phenomenon in NS--NS and NS--BH mergers for physically motivated disturbances in the mean field of flavor coherence. Our findings suggest that, differently from the core-collapse supernova case, fast flavor conversions seem to be unavoidable in compact mergers and could have major consequences for the jet dynamics and the synthesis of elements above the remnant disk.

    ↳ astro-ph.HEhep-phnucl-thPRD(2017)·147 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.