Wed·Sep 7, 2016Wednesday·September 7, 2016

1. 01*

   keV Sterile Neutrino Dark Matter from Singlet Scalar Decays: The Most General Case

   Johannes König🇩🇪 · Alexander Merle🇩🇪 · Maximilian Totzauer🇩🇪

   We investigate the early Universe production of sterile neutrino Dark Matter by the decays of singlet scalars. All previous studies applied simplifying assumptions and/or studied the process only on the level of number densities, which makes it impossible to give statements about cosmic structure formation. We overcome these issues by dropping all simplifying assumptions (except for one we showed earlier to work perfectly) and by computing the full course of Dark Matter production on the level of non-thermal momentum distribution functions. We are thus in the position to study all aspects of the resulting settings and apply all relevant bounds in a reliable manner. We have a particular focus on how to incorporate bounds from structure formation on the level of the linear power spectrum, since the simplistic estimate using the free-streaming horizon clearly fails for highly non-thermal distributions. Our work comprises the most detailed and comprehensive study of sterile neutrino Dark Matter production by scalar decays presented so far.

   hep-phastro-ph.COastro-ph.GAJCAP(2016)·126 citations
2. 02*

   Next-to-leading order unitarity fits in Two-Higgs-Doublet models with soft ${\mathbb{Z}}_2$ breaking

   Vincenzo Cacchio🇮🇹 · Debtosh Chowdhury🇮🇹 · Otto Eberhardt🇮🇹 · Christopher W. Murphy🇮🇹

   We fit the next-to-leading order unitarity conditions to the Two-Higgs-Doublet model with a softly broken ${\mathbb{Z}}_2$ symmetry. In doing so, we alleviate the existing uncertainty on how to treat higher order corrections to quartic couplings of its Higgs potential. A simplified approach to implementing the next-to-leading order unitarity conditions is presented. These new bounds are then combined with all other relevant constraints, including the complete set of LHC Run I data. The upper $95\%$ bounds we find are $4.2$ on the absolute values of the quartic couplings, and $235$ GeV ($100$ GeV) for the mass degeneracies between the heavy Higgs particles in the type I (type II) scenario. In type II, we exclude an unbroken ${\mathbb{Z}}_2$ symmetry with a probability of $95\%$. All fits are performed using the open-source code HEPfit.

   hep-phhep-exJHEP(2016)·88 citations
3. 03*

   The Dynamical Response of Dark Matter to Galaxy Evolution Affects Direct-Detection Experiments

   Michael S. Petersen🇺🇸 · Neal Katz🇺🇸 · Martin D. Weinberg🇺🇸

   Over a handful of rotation periods, dynamical processes in barred galaxies induce non-axisymmetric structure in dark matter halos. Using n-body simulations of a Milky Way-like barred galaxy, we identify both a trapped dark-matter component, a shadow bar, and a strong response wake in the dark-matter distribution that affects the predicted dark-matter detection rates for current experiments. The presence of a baryonic disk together with well-known dynamical processes (e.g. spiral structure and bar instabilities) increase the dark matter density in the disk plane. We find that the magnitude of the combined stellar and shadow bar evolution, when isolated from the effect of the axisymmetric gravitational potential of the disk, accounts for >30% of this overall increase in disk-plane density. This is significantly larger that of previously claimed deviations from the standard halo model. The dark-matter density and kinematic wakes driven by the Milky Way bar increase the detectability of dark matter overall, especially for the experiments with higher $v_{min}$. These astrophysical features increase the detection rate by more than a factor of two when compared to the standard halo model and by a factor of ten for experiments with high minimum recoil energy thresholds. These same features increase (decrease) the annual modulation for low (high) minimum recoil energy experiments. We present physical arguments for why these dynamics are generic for barred galaxies such as the Milky Way rather than contingent on a specific galaxy model.

   hep-phastro-ph.GAPRD(2016)·15 citations
4. 04*

   Revisiting Uraltsev's BPS limit for Heavy Quarks

   Johannes Heinonen🇩🇪 · Thomas Mannel🇩🇪

   Motivated by the recent experimental data of the values of the Heavy Quark Expansion parameters, in particular the spin-orbit and Darwin terms, we argue that nature actually may be close to a limit of QCD which has been suggested by Uraltsev more than ten years ago. Assuming that this limit is not accidental, we derive the relations among the Heavy Quark Expansion parameters that occur up to the order 1/mb^5.

   hep-ph6 citations
5. 05*

   Quantum and Classical Behavior in Interacting Bosonic Systems

   Mark P. Hertzberg🇺🇸

   It is understood that in free bosonic theories, the classical field theory accurately describes the full quantum theory when the occupancy numbers of systems are very large. However, the situation is less understood in interacting theories, especially on time scales longer than the dynamical relaxation time. Recently there have been claims that the quantum theory deviates spectacularly from the classical theory on this time scale, even if the occupancy numbers are extremely large. Furthermore, it is claimed that the quantum theory quickly thermalizes while the classical theory does not. The evidence for these claims comes from noticing a spectacular difference in the time evolution of expectation values of quantum operators compared to the classical micro-state evolution. If true, this would have dramatic consequences for many important phenomena, including laboratory studies of interacting BECs, dark matter axions, preheating after inflation, etc. In this work we critically examine these claims. We show that in fact the classical theory can describe the quantum behavior in the high occupancy regime, even when interactions are large. The connection is that the expectation values of quantum operators in a single quantum micro-state are approximated by a corresponding classical ensemble average over many classical micro-states. Furthermore, by the ergodic theorem, a classical ensemble average of local fields with statistical translation invariance is the spatial average of a single micro-state. So the correlation functions of the quantum and classical field theories of a single micro-state approximately agree at high occupancy, even in interacting systems. Furthermore, both quantum and classical field theories can thermalize, when appropriate coarse graining is introduced, with the classical case requiring a cutoff on low occupancy UV modes. We discuss applications of our results.

   hep-phastro-ph.COhep-thquant-phJCAP(2016)·55 citations
6. 06*

   The remnant CP transformation and its implications

   Felix Gonzalez-Canales🇲🇽

   In the context of remnant CP transformations, I briefly discuss a generalized $\mu -\tau$ reflection symmetry, where the "Majorana" phases have CP conserving values, which are directly related with the CP parities of neutrino states. Also, one finds that the "Dirac-like" CP violation phase is correlated with the atmospheric mixing angle, giving important phenomenological implications for current and future long baseline oscillation neutrino experiments.

   hep-phJ.Phys.Conf.Ser.(2016)·1 citation
7. 07*

   Chiral corrections to the Adler-Weisberger sum rule

   Silas R. Beane🇺🇸 · Natalie Klco🇺🇸

   The Adler-Weisberger sum rule for the nucleon axial-vector charge, $g_A$, offers a unique signature of chiral symmetry and its breaking in QCD. Its derivation relies on both algebraic aspects of chiral symmetry, which guarantee the convergence of the sum rule, and dynamical aspects of chiral symmetry breaking---as exploited using chiral perturbation theory---which allow the rigorous inclusion of explicit chiral symmetry breaking effects due to light-quark masses. The original derivations obtained the sum rule in the chiral limit and, without the benefit of chiral perturbation theory, made various attempts at extrapolating to non-vanishing pion masses. In this paper, the leading, universal, chiral corrections to the chiral-limit sum rule are obtained. Using PDG data, a recent parametrization of the pion-nucleon total cross-sections in the resonance region given by the SAID group, as well as recent Roy-Steiner equation determinations of subthreshold amplitudes, threshold parameters, and correlated low-energy constants, the Adler-Weisberger sum rule is confronted with experimental data. With uncertainty estimates associated with the cross-section parameterization, the Goldberger-Treimann discrepancy, and the truncation of the sum rule at $\mathcal{O}(M_{\pi }^4)$ in the chiral expansion, this work finds $g_A=1.248\pm 0.010\pm 0.007\pm 0.013$.

   hep-phnucl-thPRD(2016)·3 citations
8. 08*

   $B\to K^{\ast }(\to K\pi ){\ell }^{+}{\ell }^{-}$ theory and the global picture: What's next?

   Bernat Capdevila (Barcelona, Autonoma U. and IFAE)🇪🇸 · Sebastien Descotes-Genon (Orsay, LPT)🇫🇷 · Lars Hofer (ICC, Barcelona U.)🇪🇸 · Joaquim Matias (Barcelona, Autonoma U. and IFAE)🇪🇸 · Javier Virto (Siegen U.)🇨🇭

   The present status of the LHC anomalies found in exclusive semileptonic $b\to s{\ell }^{+}{\ell }^{-}$ decays is discussed with special emphasis on the exclusive 4-body angular distribution $B\to K^{\ast }(\to K\pi ){\ell }^{+}{\ell }^{-}$. The treatment of hadronic uncertainties in this mode is briefly reviewed, and some of the analyses in the literature are critically reassessed. The global picture provided by the global fit points to a coherent pattern of deviations with a significance substantially above 4$\sigma$ for different New Physics scenarios. Finally, we propose as the next step in the field to focus on the study of optimized observables that compare electron and muon modes, sensitive to lepton-flavour universality violations and free from hadronic uncertainties (including charm) in the SM, the so called $Q_i$ observables.

   hep-phhep-exPoS(2016)·8 citations
9. 09*

   Chirally Invariant Avatar in a Model of Neutrinos with Light Cone Reflection Symmetry

   Alan Chodos🇺🇸

   In previous work we developed a model of neutrinos based on a new symmetry, Light Cone Reflection (LCR), that interchanges spacelike and timelike intervals. In this paper we start with the four-dimensional model, and construct a two-dimensional avatar that obeys the same equations of motion, and preserves both the light-cone reflection symmetry and the chiral symmetry of the original theory. The avatar also contains the interaction that rendered the four-dimensional model gauge invariant. In an addendum, we make some remarks about how to determine the scalar field that enters into the definition of the LCR-covariant derivative.

   hep-phhep-th3 citations
10. 10*

    Large scale separation and resonances within LHC range from a prototype BSM model

    Anna Hasenfratz🇺🇸 · Claudio Rebbi🇺🇸 · Oliver Witzel🇬🇧

    Many theories describing physics beyond the Standard Model rely on a large separation of scales. Large scale separation arises in models with mass-split flavors if the system is conformal in the ultraviolet but chirally broken in the infrared. Because of the conformal fixed point, these systems exhibit hyperscaling and a highly constrained resonance spectrum. We derive hyperscaling relations and investigate the realization of one such system with four light and eight heavy flavors. Our numerical simulations confirm that both light-light and heavy-heavy resonance masses show hyperscaling and depend only on the ratio of the light and heavy flavor masses. The heavy-heavy spectrum is qualitatively different from QCD and exhibits quarkonia with masses not proportional to the constituent quark mass. These resonances are only a few times heavier than the light-light ones, which would put them within reach of the LHC.

    hep-phhep-latPLB(2017)·37 citations
11. 11*

    The 1-loop vacuum polarization for a graphene-like medium in an external magnetic field; corrections to the Coulomb potential

    Bruno Machet🇫🇷

    I calculate the 1-loop vacuum polarization ${\Pi }_{\mu \nu }(k,B,a)$ for a photon of momentum $k=(\hat{k},k_3)$ interacting with the electrons of a thin medium of thickness $2a$ simulating graphene, in the presence of a constant and uniform external magnetic field $B$ orthogonal to it (parallel to $k_3$). Calculations are done with the techniques of Schwinger, adapted to the geometry and Hamiltonian under scrutiny. The situation gets more involved than for the electron self-energy because the photon is now allowed to also propagate outside the medium. This makes ${\Pi }_{\mu \nu }$ factorize into a quantum, "reduced" $T_{\mu \nu }(\hat{k},B)$ and a transmittance function $V(k,a)$, in which the geometry of the sample and the resulting confinement of the $\gamma e^{+}{e}^{-}$ vertices play major roles. This drags the results away from reduced QED${}_{3+1}$ on a 2-brane. The finiteness of $V$ at $k^2=0$ is an essential ingredient to fulfill suitable renormalization condition for ${\Pi }_{\mu \nu }$ and to fix the corresponding counterterms. Their connection with the transversality of ${\Pi }_{\mu \nu }$ is investigated. The corrections to the Coulomb potential and their dependence on $B$ strongly differ from QED${}_{3+1}$.

    hep-ph1 citation
12. 12*

    NLO QCD+EW for V+jets

    Marek Schönherr🇨🇭 · Stefan Kallweit🇩🇪 · Jonas M. Lindert🇨🇭 · Stefano Pozzorini🇨🇭 · Philipp Maierhöfer🇩🇪

    In this contribution recent results regarding the NLO electroweak corrections for vector boson production in association with jets are presented. Besides discussing the phenomenology of the fixed-order results, their corporation in existing NLO QCD parton shower matched and merged calculations, which can directly be used in experimental analyses, will be shown.

    hep-phPoS(2016)·8 citations
13. 13*

    Goldstone-Type Pseudoscalar Mesons: Instantaneous Bethe-Salpeter Models

    Wolfgang Lucha🇦🇹

    A nontrivial instantaneous variant of the Bethe-Salpeter formalism allows us to discuss massless pseudoscalar mesons from a configuration-space-potential point of view.

    hep-phnucl-thEPJ Web Conf.(2017)·5 citations
14. 14*

    Two-loop Induced Majorana Neutrino Mass in a Radiatively Induced Quark and Lepton Mass Model

    Takaaki Nomura🇰🇷 · Hiroshi Okada🇹🇼

    A two-loop induced radiative neutrino model is proposed as an extension of our previous work in which the first and second generation standard model fermion masses are generated at one-loop level in both quark and lepton sectors. Then we discuss current neutrino oscillation data, lepton flavor violations, muon anomalous magnetic moment, and a bosonic dark matter candidate, for both the normal and inverted neutrino mass hierarchy. Our numerical analysis shows that less hierarchical Yukawa coupling constants can fit the experimental data with TeV scale dark matter.

    hep-phPRD(2016)·21 citations
15. 15*

    $B^{+}\to K^{-}{\pi }^{+}{\pi }^{+}$: three-body final state interactions and $K\pi$ isospin states

    J. H. Alvarenga Nogueira🇧🇷 · T. Frederico🇧🇷 · O. Lourenço🇧🇷

    Final state interactions are considered to formulate the $B$ meson decay amplitude for the $K\pi \pi$ channel. The Faddeev decomposition of the Bethe-Salpeter equation is used in order to build a relativistic three-body model within the light-front framework. The S-wave scattering amplitude for the $K\pi$ system is considered in the $1/2$ and $3/2$ isospin channels with the set of inhomogeneous integral equations solved perturbatively. In comparison with previous results for the $D$ meson decay in the same channel, one has to consider the different partonic processes, which build the source amplitudes, and the larger absorption to other decay channels appears, that are important features to be addressed. As in the $D$ decay case, the convergence of the rescattering perturbative series is also achieved with two-loop contributions.

    hep-phFew Body Syst.(2017)·6 citations
16. 16*

    Resurrection of large lepton number asymmetries from neutrino flavor oscillations

    Gabriela Barenboim🇪🇸 · William H. Kinney🇺🇸 · Wan-Il Park🇪🇸

    We numerically solve the evolution equations of neutrino three-flavor density matrices, and show that, even if neutrino oscillations mix neutrino flavors, large lepton number asymmetries are still allowed in certain limits by Big Bang Nucleosynthesis (BBN).

    hep-phastro-ph.COPRD(2017)·63 citations
17. 17*

    Generalized Skyrme model with the loosely bound potential

    Sven Bjarke Gudnason🇨🇳 · Baiyang Zhang🇨🇳 · Nana Ma🇨🇳

    We study a generalization of the loosely bound Skyrme model which consists of the Skyrme model with a sixth-order derivative term - motivated by its fluid-like properties - and the second-order loosely bound potential - motivated by lowering the classical binding energies of higher-charged Skyrmions. We use the rational map approximation for the Skyrmion of topological charge B=4, calculate the binding energy of the latter and estimate the systematic error in using this approximation. In the parameter space that we can explore within the rational map approximation, we find classical binding energies as low as 1.8% and once taking into account the contribution from spin-isospin quantization we obtain binding energies as low as 5.3%. We also calculate the contribution from the sixth-order derivative term to the electric charge density and axial coupling.

    hep-phhep-thnucl-thPRD(2016)·28 citations
18. 18*

    Protophobic Light Vector Boson as a Mediator to the Dark Sector

    Teppei Kitahara🇩🇪 · Yasuhiro Yamamoto🇯🇵

    The observation of a protophobic 16.7 MeV vector boson has been reported by a ${}^8$Be nuclear transition experiment. Such a new particle could mediate between the Standard Model and a dark sector, which includes the dark matter. In this paper, we show some simple models of the dark matter which satisfy the thermal relic abundance under the current experimental bounds from the direct and the indirect detections. In a model, it is found that an appropriate self-scattering cross section to solve the small scale structure puzzles can be achieved.

    hep-phPRD(2017)·48 citations
19. 19*

    Soft gluon resummation at fixed invariant mass for associated $t\bar{t}H$ production at the LHC

    Anna Kulesza🇩🇪 · Leszek Motyka🇵🇱 · Tomasz Stebel🇵🇱 · Vincent Theeuwes🇺🇸

    In the following we present our results on resummation of invariant mass threshold corrections for the $2\to 3$ type hadronic production processes in the Mellin moment space formalism. This method is applied to the associated Higgs boson production process $pp\to t\bar{t}H$ at the LHC. The results for the total cross section, the differential distribution with respect to the invariant mass and their uncertainties are presented.

    hep-phPoS(2016)·13 citations
20. 20*

    Off-shell Top Quarks with One Jet at the LHC: A comprehensive analysis at NLO QCD

    G. Bevilacqua🇭🇺 · H. B. Hartanto🇩🇪 · M. Kraus🇩🇪 · M. Worek🇩🇪

    We present a comprehensive study of the production of top quark pairs in association with one hard jet in the di-lepton decay channel at the LHC. Our predictions, accurate at NLO in QCD, focus on the LHC Run II with a center-of-mass energy of 13 TeV. All resonant and non-resonant contributions at the perturbative order $\mathcal{O}({\alpha }_s^4{\alpha }^4)$ are taken into account, including irreducible backgrounds to $t\bar{t}j$ production, interferences and off-shell effects of the top quark and the $W$ gauge boson. We extensively investigate the dependence of our results upon variation of renormalisation and factorisation scales and parton distribution functions in the quest for an accurate estimate of the theoretical uncertainties. Additionally, we explore a few possibilities for a dynamical scale choice with the goal of stabilizing the perturbative convergence of the differential cross sections far away from the $t\bar{t}$ threshold. Results presented here are particularly relevant for searches of new physics as well as for precise measurements of the top-quark fiducial cross sections and top-quark properties at the LHC.

    hep-phJHEP(2016)·73 citations
21. 21*

    Possible Explanation of the Electron Positron Anomaly at 17 MeV in ${}^{8}Be$ Transitions Through a Light Pseudoscalar

    Ulrich Ellwanger🇫🇷 · Stefano Moretti🇬🇧

    We estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the ${}^{8}Be$ anomaly observed in the Atomki pair spectrometer experiment. The resulting couplings of A to up and down type quarks are about 0.3 times the coupling of the standard Higgs boson. Then constraints from K and B decays require that loop contributions to flavour changing vertices cancel at least at the 10% level. Constraints from beam dump experiments require the coupling of A to electrons to be larger than about 4 times the coupling of the standard Higgs boson, leading to a short enough A life time consistent with an explanation of the anomaly.

    hep-phJHEP(2016)·120 citations
22. 22*

    Conditional entropy of glueball states

    Alex E. Bernardini🇧🇷 · Nelson R. F. Braga🇧🇷 · Roldao da Rocha🇧🇷

    The conditional entropy of glueball states is calculated using a holographic description. Glueball states are represented by a supergravity dual picture, consisting of a 5-dimensional graviton-dilaton action of a dynamical holographic AdS/QCD model. The conditional entropy is studied as a function of the glueball spin and of the mass, providing information about the stability of the glueball states.

    ↳ hep-thhep-phPLB(2017)·79 citations
23. 23*

    Perturbed black holes in Einstein-dilaton-Gauss-Bonnet gravity: Stability, ringdown, and gravitational-wave emission

    Jose Luis Blázquez-Salcedo🇩🇪 · Caio F. B. Macedo🇵🇹 · Vitor Cardoso🇵🇹 · Valeria Ferrari🇮🇹 · Leonardo Gualtieri🇮🇹 · Fech Scen Khoo🇩🇪 · Jutta Kunz🇩🇪 · Paolo Pani🇮🇹

    Gravitational waves emitted by distorted black holes---such as those arising from the coalescence of two neutron stars or black holes---carry not only information about the corresponding spacetime but also about the underlying theory of gravity. Although general relativity remains the simplest, most elegant and viable theory of gravitation, there are generic and robust arguments indicating that it is not the ultimate description of the gravitational universe. Here we focus on a particularly appealing extension of general relativity, which corrects Einstein's theory through the addition of terms which are second order in curvature: the topological Gauss-Bonnet invariant coupled to a dilaton. We study gravitational-wave emission from black holes in this theory, and {\bf(i)} find strong evidence that black holes are linearly (mode) stable against both axial and polar perturbations; {\bf(ii)} discuss how the quasinormal modes of black holes can be excited during collisions involving black holes, and finally {\bf(iii)} show that future ringdown detections with large signal-to-noise ratio would improve current constraints on the coupling parameter of the theory.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2016)·276 citations
24. 24*

    Secondary Cosmic Positrons in an Inhomogeneous Diffusion Model

    Rolf Kappl🇩🇪 · Annika Reinert🇩🇪

    One aim of cosmic ray measurements is the search for possible signatures of annihilating or decaying dark matter. The so-called positron excess has attracted a lot of attention in this context. On the other hand it has been proposed that the data might challenge the established diffusion model for cosmic ray propagation. We investigate an inhomogeneous diffusion model by solving the corresponding equations analytically. Depending on the propagation parameters we find that the spectral features of the positron spectrum are affected significantly. We also discuss the influence of the inhomogeneity on hadronic spectra.

    ↳ astro-ph.HEhep-phPhys.Dark Univ.(2017)·7 citations
25. 25*

    A Dynamical Mechanism for Large Volumes with Consistent Couplings

    Steven Abel🇬🇧

    A mechanism for addressing the 'decompactification problem' is proposed, which consists of balancing the vacuum energy in Scherk-Schwarzed theories against contributions coming from non- perturbative physics. Universality of threshold corrections ensures that, in such situations, the stable minimum will have consistent gauge couplings for any gauge group that shares the same N = 2 beta function for the bulk excitations as the gauge group that takes part in the minimisation. Scherk- Schwarz compactification from 6D to 4D in heterotic strings is discussed explicitly, together with two alternative possibilities for the non-perturbative physics, namely metastable SQCD vacua and a single gaugino condensate. In the former case, it is shown that modular symmetries gives various consistency checks, and allow one to follow soft-terms, playing a similar role to R-symmetry in global SQCD. The latter case is particularly attractive when there is nett Bose-Fermi degeneracy in the massless sector. In such cases, because the original Casimir energy is generated entirely by excited and/or non-physical string modes, it is completely immune to the non-perturbative IR physics. The large separation between UV and IR contributions to the potential greatly simplifies the analysis of stabilisation, and is a general possibility that has not been considered before.

    ↳ hep-thhep-phJHEP(2016)·15 citations
26. 26*

    Beyond Special Relativity at second order

    J.M. Carmona🇪🇸 · J.L. Cortes🇪🇸 · J.J. Relancio🇪🇸

    The study of generic, non-linear, deformations of Special Relativity parametrized by a high-energy scale $M$, which was carried out at first order in $M$ in Phys.Rev. D86, 084032 (2012), is extended to second order. This can be done systematically through a ('generalized') change of variables from momentum variables that transform linearly. We discuss the different perspectives on the meaning of the change of variables, obtain the coefficients of modified composition laws and Lorentz transformations at second order, and work out how $\kappa$-Poincaré, the most commonly used example in the literature, is reproduced as a particular case of the generic framework exposed here.

    ↳ hep-thgr-qchep-phPRD(2016)·26 citations
27. 27*

    Remarks on Non-BPS String Amplitudes and Their All Order ${\alpha }^{\prime }$ Contact Interactions in IIB, IIA

    Ehsan Hatefi🇦🇹

    We explore the entire form of S-Matrix elements of a potential $C_{n-1}$ Ramond-Ramond (RR) form field, a tachyon and two transverse scalar fields on both world volume and transverse directions of type IIB and IIA superstring theories. Apart from $<V_{C^{-2}}{V}_{{\varphi }^0}{V}_{{\varphi }^0}{V}_{T^0}>$ the other scattering amplitude, namely $<V_{C^{-1}}{V}_{{\varphi }^{-1}}{V}_{{\varphi }^0}{V}_{T^0}>$ is also revealed. We then start to compare all singularity structures of symmetric and asymmetric analysis, generating all infinite singularity structures as well as all order ${\alpha }^{\prime }$ contact interactions on the whole directions. This leads to deriving various new contact terms and several new restricted Bianchi identities in both type IIB and IIA. It is also shown that just some of the new couplings of type IIB (IIA) string theory can be re-verified in an Effective Field Theory (EFT) by pull-back of branes. To construct the rest of S-matrix elements one needs to first derive restricted world volume (or bulk) Bianchi identities and then discover new EFT couplings in both type IIB and IIA. Finally the presence of commutator of scalar fields inside the exponential of Wess-Zumino action for non-BPS branes has been confirmed as well.

    ↳ hep-thgr-qchep-phJHEP(2017)·7 citations
28. 28*

    6d Dirac fermion on a rectangle; scrutinizing boundary conditions, mode functions and spectrum

    Yukihiro Fujimoto🇯🇵 · Kouhei Hasegawa🇯🇵 · Kenji Nishiwaki🇰🇷 · Makoto Sakamoto🇯🇵 · Kentaro Tatsumi🇯🇵

    We classify possible boundary conditions of a 6d Dirac fermion $\Psi$ on a rectangle under the requirement that the 4d Lorentz structure is maintained, and derive the profiles and spectrum of the zero modes and nonzero KK modes under the two specific boundary conditions, (i) 4d-chirality positive components being zero at the boundaries and (ii) 2d-chirality positive components being zero at the boundaries. In the case of (i), twofold degenerated chiral zero modes appear which are localized towards specific directions of the rectangle pointed by an angle parameter $\theta$. This leads to an implication for a new direction of pursuing the origin of three generations in the matter fields of the standard model, even though triple-degenerated zero modes are not realized in the six dimensions. The emergence of the angle parameter $\theta$ originates from a rotational symmetry in the degenerated chiral zero modes on the rectangle extra dimensions since they do not feel the boundaries. In the case of (ii), this rotational symmetry is promoted to the two-dimensional conformal symmetry though no chiral massless zero mode appears. We also discuss the correspondence between our model on a rectangle and orbifold models in some details.

    ↳ hep-thhep-phNPB(2017)·10 citations
29. 29*

    Baryon Number Fluctuations in Quasi-particle Model

    Ameng Zhao🇨🇳 · Xiaofeng Luo🇨🇳 · Hongshi Zong🇨🇳

    Baryon number fluctuations are sensitive to the QCD phase transition and QCD critical point. According to the Feynman rules of finite-temperature field theory, we calculated various order moments and cumulants of the baryon number distributions in the quasi-particle model of quark gluon plasma. Furthermore, we compared our results with the experimental data measured by the STAR experiment at RHIC. It is found that the experimental data can be well described by the model for the colliding energies above 30 GeV and show large discrepancies at low energies. It can put new constraint on qQGP model and also provide a baseline for the QCD critical point search in heavy-ion collisions at low energies.

    ↳ nucl-thhep-exhep-phnucl-exEPJC(2017)·6 citations
30. 30*

    Exploring Nf=2+1 QCD thermodynamics from the gradient flow

    Yusuke Taniguchi🇯🇵 · Shinji Ejiri🇯🇵 · Ryo Iwami🇯🇵 · Kazuyuki Kanaya🇯🇵 · Masakiyo Kitazawa🇯🇵 · Hiroshi Suzuki🇯🇵 · Takashi Umeda🇯🇵 · Naoki Wakabayashi🇯🇵

    The energy-momentum tensor plays an important role in QCD thermodynamics. Its expectation value contains information of the pressure and the energy density as its diagonal part. Further properties like viscosity and specific heat can be extracted from its correlation function. Recently a new method based on the gradient flow was introduced to calculate the energy-momentum tensor on the lattice, and has been successfully applied to quenched QCD. In this paper, we apply the gradient flow method to calculate the energy-momentum tensor in (2+1)-flavor QCD. As the first application of the method with dynamical quarks, we study at a single but fine lattice spacing a=0.07 fm with heavy u and d quarks ($m_{\pi }/m_{\rho }=0.63$) and approximately physical s quark. Performing simulations on lattices with Nt=16 to 4, the temperature range of T=174-697 MeV is covered. We find that the results of the pressure and the energy density by the gradient flow method are consistent with the previous results using the T-integration method at T<280 MeV, while the results show disagreement at T>350 MeV (Nt<8), presumably due to the small-Nt lattice artifact of $O((aT{)}^2)=O(1/N_t^2)$. We also apply the gradient flow method to evaluate the chiral condensate taking advantage of the gradient flow method that renormalized quantities can be directly computed avoiding the difficulty of explicit chiral violation with lattice quarks. We compute the renormalized chiral condensate in the MS-bar scheme at renormalization scale $\mu =2$ GeV with a high precision to study the temperature dependence of the chiral condensate and its disconnected susceptibility. Even with the Wilson-type quark action, we obtain the chiral condensate and its disconnected susceptibility showing a clear signal of pseudocritical temperature at T~190 MeV related to the chiral restoration crossover.

    ↳ hep-lathep-phPRD(2017)·72 citations
31. 31*

    Connected, Disconnected and Strange Quark Contributions to HVP

    Johan Bijnens🇸🇪 · Johan Relefors (Lund)🇸🇪

    We calculate all neutral vector two-point functions in Chiral Perturbation Theory (ChPT) to two-loop order and use these to estimate the ratio of disconnected to connected contributions as well as contributions involving the strange quark. We extend the ratio of $-1/10$ derived earlier in two flavour ChPT at one-loop order to a large part of the higher order contributions and discuss corrections to it. Our final estimate of the ratio disconnected to connected is negative and a few % in magnitude.

    ↳ hep-lathep-phJHEP(2016)·14 citations
32. 32*

    The Waves and the Sigmas (To Say Nothing of the 750 GeV Mirage)

    Giulio D'Agostini🇮🇹

    This paper shows how p-values do not only create, as well known, wrong expectations in the case of flukes, but they might also dramatically diminish the `significance' of most likely genuine signals. As real life examples, the 2015 first detections of gravitational waves are discussed. The March 2016 statement of the American Statistical Association, warning scientists about interpretation and misuse of p-values, is also reminded and commented. (The paper is complemented with some remarks on past, recent and future claims of discoveries based on sigmas from Particles Physics.)

    ↳ physics.data-angr-qchep-phmath.HO+23 citations

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