Tue·Apr 12, 2016Tuesday·April 12, 2016

1. 01*

   Displaced vertex searches for sterile neutrinos at future lepton colliders

   Stefan Antusch🇨🇭 · Eros Cazzato🇨🇭 · Oliver Fischer🇨🇭

   We investigate the sensitivity of future lepton colliders to displaced vertices from the decays of long-lived heavy (almost sterile) neutrinos with electroweak scale masses and detectable time of flight. As future lepton colliders we consider the FCC-ee, the CEPC, and the ILC, searching at the Z-pole and at the center-of-mass energies of 240, 350 and 500 GeV. For a realistic discussion of the detector response to the displaced vertex signal and the Standard Model background we consider the ILC's Silicon Detector (SiD) as benchmark for the future lepton collider detectors. We find that displaced vertices constitute a powerful search channel for sterile neutrinos, sensitive to squared active-sterile mixing angles as small as $10^{-11}$.

   hep-phJHEP(2016)·157 citations
2. 02*

   QCD fixed points: Banks-Zaks scenario or dynamical gluon mass generation?

   J.D.Gomez🇧🇷 · A.A.Natale🇧🇷

   Fixed points in QCD can appear when the number of quark flavors ($N_f$) is increased above a certain critical value as proposed by Banks and Zaks (BZ). There is also the possibility that QCD possess an effective charge indicating an infrared frozen coupling constant. In particular, an infrared frozen coupling associated to dynamical gluon mass generation (DGM) does lead to a fixed point even for a small number of quarks. We compare the BZ and DGM mechanisms, their $\beta$ functions and fixed points, and within the approximations of this work, which rely basically on extrapolations of the dynamical gluon masses at large $N_f$, we verify that near the so called QCD conformal window both cases exhibit fixed points at similar coupling constant values ($g^{\ast }$). We argue that the states of minimum vacuum energy, as a function of the coupling constant up to $g^{\ast }$ and for several $N_f$ values, are related to the dynamical gluon mass generation mechanism.

   hep-phhep-latInt.J.Mod.Phys.A(2017)·3 citations
3. 03*

   Mixed Heavy-Light Matching in the Universal One-Loop Effective Action

   Sebastian A. R. Ellis🇺🇸 · Jeremie Quevillon🇬🇧 · Tevong You🇬🇧 · Zhengkang Zhang🇺🇸

   Recently, a general result for evaluating the path integral at one loop was obtained in the form of the Universal One-Loop Effective Action. It may be used to derive effective field theory operators of dimensions up to six, by evaluating the traces of matrices in this expression, with the mass-dependence encapsulated in the universal coefficients. Here we show that it can account for loops of mixed heavy-light particles in the matching procedure. Our prescription for computing these mixed contributions to the Wilson coefficients is conceptually simple. Moreover it has the advantage of maintaining the universal structure of the effective action, which we illustrate using the example of integrating out a heavy electroweak triplet scalar coupling to a light Higgs doublet. Finally we also identify new structures that were previously neglected in the universal results.

   hep-phhep-thPLB(2016)·93 citations
4. 04*

   Chilly Dark Sectors and Asymmetric Reheating

   Peter Adshead🇺🇸 · Yanou Cui🇺🇸 · Jessie Shelton🇺🇸

   In a broad class of theories, the relic abundance of dark matter is determined by interactions internal to a thermalized dark sector, with no direct involvement of the Standard Model (SM). We point out that these theories raise an immediate cosmological question: how was the dark sector initially populated in the early universe? Motivated in part by the difficulty of accommodating large amounts of entropy carried in dark radiation with cosmic microwave background measurements of the effective number of relativistic species at recombination, $N_{\mathrm{eff}}$, we aim to establish which admissible cosmological histories can populate a thermal dark sector that never reaches thermal equilibrium with the SM. The minimal cosmological origin for such a dark sector is asymmetric reheating, when the same mechanism that populates the SM in the early universe also populates the dark sector at a lower temperature. Here we demonstrate that the resulting inevitable inflaton-mediated scattering between the dark sector and the SM can wash out a would-be temperature asymmetry, and establish the regions of parameter space where temperature asymmetries can be generated in minimal reheating scenarios. Thus obtaining a temperature asymmetry of a given size either restricts possible inflaton masses and couplings or necessitates a non-minimal cosmology for one or both sectors. As a side benefit, we develop techniques for evaluating collision terms in the relativistic Boltzmann equation when the full dependence on Bose-Einstein or Fermi-Dirac phase space distributions must be retained, and present several new results on relativistic thermal averages in an appendix.

   hep-phastro-ph.COJHEP(2016)·132 citations
5. 05*

   Unitarity Constraints on non-minimal Universal Extra Dimensional Model

   Tapoja Jha🇮🇳

   We examine the unitarity constraints in gauge and scalar sectors of non-minimal Universal Extra Dimensional model. We show that some of the tree-level two-body scattering amplitudes in gauge and scalar sectors do not respect partial wave unitarity. Unitarity analysis of this model leads to an upper bound on corresponding boundary-localized (BLT) parameter which depends on the maximum number of Kaluza-Klein (KK) mode considered in the analysis. This upper bound of the relevant BLT parameter decreases with the increasing KK-modes. The results are, in effect, independent of the inverse of compactifiaction radius. The upper bound on BLT parameter also results in a lower bound on gauge and scalar KK-masses.

   hep-phJ.Phys.G(2018)·11 citations
6. 06*

   Plateau Inflation in SUGRA-MSSM

   Girish Kumar Chakravarty🇮🇳 · Gaveshna Gupta🇮🇳 · Gaetano Lambiase🇮🇹 · Subhendra Mohanty🇮🇳

   We explored a Higgs inflationary scenario in the SUGRA embedding of the MSSM in Einstein frame where the inflaton is contained in the $SU(2)$ Higgs doublet. We include all higher order non-renormalizable terms to the MSSM superpotential and an appropriate Kähler potential which can provide slow-roll inflaton potential in the $D-$flat direction. In this model, a plateau-like inflation potential can be obtained if the imaginary part of the neutral Higgs acts as the inflaton. The inflationary predictions of this model are consistent with the latest CMB observations. The model represents a successful Higgs inflation scenario in the context of Supergravity and it is compatible with Minimal Supersymmetric extension of the Standard Model.

   hep-phastro-ph.COgr-qcPLB(2016)·13 citations
7. 07*

   Chiral phase transition and meson spectrum in improved soft-wall AdS/QCD

   Zhen Fang🇨🇳 · Yue-Liang Wu🇨🇳 · Lin Zhang🇨🇳

   We investigate in detail the chiral thermal transition of QCD in an improved soft-wall AdS/QCD model with a simply modified 5D conformal mass of the bulk scalar field. We also present a calculation in this model for the light meson spectra and other low-energy characteristic quantities including the pion form factor, the pi-rho coupling constant and the decay constants of pi, rho, a_1, which are shown to result in a good agreement with experimental data except for the pion decay constant. The thermal behavior of chiral condensate is studied. It is found that such a simply improved soft-wall model incorporates the crossover behavior of chiral thermal transition indicated by lattice simulations. The expected chiral transition temperature can be obtained.

   hep-phPLB(2016)·48 citations
8. 08*

   Anomalous Dimensions of Conformal Baryons

   Claudio Pica🇩🇰 · Francesco Sannino🇩🇰

   We determine the anomalous dimensions of baryon operators for the three color theory as function of the number of massless flavours within the conformal window to the maximum known order in perturbation theory. We show that the anomalous dimension of the baryon is controllably small, within the $\delta$-expansion, for a wide range of number of flavours. We also find that this is always smaller than the anomalous dimension of the fermion mass operator. These findings challenge the partial compositeness paradigm.

   hep-phhep-lathep-thPRD(2016)·37 citations
9. 09*

   Determination of the compositeness of resonances from decays: the case of the $B_s^0\to J/\psi f_1(1285)$

   R. Molina🇺🇸 · M. Döring🇺🇸 · E. Oset🇪🇸

   We develop a method to measure the amount of compositeness of a resonance, mostly made as a bound state of two hadrons, by simultaneously measuring the rate of production of the resonance and the mass distribution of the two hadrons close to threshold. By using different methods of analysis we conclude that the method allows one to extract the value of 1-Z with about $0.1$ of uncertainty. The method is applied to the case of the ${\bar{B}}_s^0\to J/\psi f_1(1285)$ decay, by looking at the resonance production and the mass distribution of $K{\bar{K}}^{\ast }$.

   hep-phPRD(2016)·12 citations
10. 10*

    Sum Rules for Leptons

    Martin Spinrath🇩🇪

    There is a wide class of models which give a dynamical description of the origin of flavour in terms of spontaneous symmetry breaking of an underlying symmetry. Many of these models exhibit sum rules which relate on the one hand mixing angles and the Dirac CP phase with each other and/or on the other hand neutrino masses and Majorana phases with each other. We will briefly sketch how this happens and discuss briefly the impact of renormalisation group corrections to the mass sum rules.

    hep-phInt.J.Mod.Phys.A(2016)·2 citations
11. 11*

    Thermal photon production from gluon fusion induced by magnetic fields in relativistic heavy-ion collisions

    Alejandro Ayala🇲🇽 · Jorge David Castano-Yepes🇲🇽 · C. A. Dominguez🇿🇦 · L. A. Hernandez🇿🇦

    We compute the production of thermal photons in relativistic heavy-ion collisions by gluon fusion in the presence of an intense magnetic field, and during the early stages of the reaction. This photon yield is an excess over calculations that do not consider magnetic field effects. We add this excess to recent hydrodynamic calculations that are close to describing the experimental transverse momentum distribution in RHIC and LHC. We then show that with reasonable values for the temperature, magnetic field strength, and strong coupling constant, our results provide a very good description of such excess. These results support the idea that the origin of at least some of the photon excess observed in heavy-ion experiments may arise from magnetic field induced processes.

    hep-phhep-thnucl-exnucl-thEPJ Web Conf.(2017)·19 citations
12. 12*

    Heavy Leptonium as the Origin of the 750 GeV Diphoton Excess

    Neil D. Barrie🇦🇺 · Archil Kobakhidze🇦🇺 · Shelley Liang🇦🇺 · Matthew Talia🇦🇺 · Lei Wu🇦🇺

    We propose a hypothetical heavy leptonium, the scalar bound state of an exotic lepton-antilepton pair, as a candidate for the recent 750 GeV resonance in the early LHC Run 2 data. Such a para-leptonium is dominantly produced via photon-photon fusion at the LHC and decays into a photon pair with a significant branching fraction. In addition, our model predicts a companion spin-1 ortho-leptonium bound state, which can decay to $W^{+}{W}^{-}$, $f\bar{f}$ and three photons. Under the LHC and the electroweak precision observables bounds, we find that the observed excess of 750 GeV diphoton events can be explained within $2\sigma$ accuracy for $Y_L\approx 4.8-7.2$ for the minimal case in our scenario. The observation of the ortho-leptonium in the dilepton channel will be the smoking gun for our scenario.

    hep-phhep-ex18 citations
13. 13*

    Di-Higgs signatures from R-parity violating supersymmetry as the origin of neutrino mass

    Sanjoy Biswas🇰🇷 · Eung Jin Chun🇰🇷 · Pankaj Sharma🇦🇺

    Motivated by the naturalness and neutrino mass generation, we study a bilinear R-parity violating supersymmetric scenario with a light Higgsino-like lightest supersymmetric particle (LSP). We observe that the LSP dominantly decays to $\nu h$ in a large part of the parameter space, and thus study the pair production of electroweakinos followed by the decays ${\tilde{\chi }}_1^{\pm }\to {\tilde{\chi }}_1^0{W}^{\pm \ast }$ and ${\tilde{\chi }}_1^0\to \nu h$. This leads to an interesting signature of Higgs boson pair production associated with significantly large missing transverse energy which is grossly distinct from the di-Higgs production in the Standard Model. We investigate the perspective of probing such signatures by performing a realistic detector level simulation of both the signal and corresponding backgrounds for the high-luminosity high energy phase of the Large Hadron Collider (LHC). We also advocate some observables based on kinematical features to provide an excellent handle to suppress the backgrounds.

    hep-phJHEP(2016)·12 citations
14. 14*

    Soft-wall modelling of meson spectra

    S. S. Afonin🇷🇺

    The holographic methods inspired by the gauge/gravity correspondence from string theory have been actively applied to the hadron spectroscopy in the last eleven years. Within the phenomenological bottom-up approach, the linear Regge-like trajectories for light mesons are naturally reproduced in the so-called "Soft-wall" holographic models. I will give a very short review of the underlying ideas and technical aspects related to the meson spectroscopy. A generalization of soft-wall description of Regge trajectories to arbitrary intercept is proposed. The problem of incorporation of the chiral symmetry breaking is discussed.

    hep-phhep-thActa Phys.Polon.Supp.(2016)·7 citations
15. 15*

    Multi-Meson Model applied to $D^{+}\to K^{+}{K}^{-}{K}^{+}$

    R. T. Aoude🇧🇷 · P. C. Magalhães🇧🇷 · A. C. dos Reis🇧🇷 · M. R. Robilotta🇧🇷

    Matrix elements of weak currents involving light multi-meson states are important in many hadronic decays of both heavy leptons and heavy mesons. In this paper we focus on the latter case where the current size of the data set demands better models. The specific case of three-kaon weak matrix elements is considered and expressed as a relatively simple structure, which generalizes naturally the concept of form factor. We propose a model for the decay $D^{+}\to K^{+}{K}^{-}{K}^{+}$ as an alternative to isobar model, with free parameter predicted by the theory to be fine-tuned by a fit to data. An important qualitative outcome is that we encompass naturally all final states topologies, which involve necessarily proper multi-particle structures and cannot be decomposed into simpler two-body processes. This aspect represents a significant improvement when compared to isobar model, often employed in analyses of heavy-meson decay data.

    hep-phhep-exPoS(2016)·3 citations
16. 16*

    pMSSM SUSY and the ATLAS Z+jets+MET Excess

    Thomas G. Rizzo🇺🇸

    A possible explanation of the excesses observed by ATLAS in the Z+jets+MET channel within the p(henomenological)MSSM is discussed. We have found that the cascade of first/second generation squarks to binos to Higgsino LSPs, with judiciously chosen sparticle masses, can provide a viable scenario that is consistent with all other experimental constraints.

    hep-ph0 citations
17. 17*

    Heavy-quark mass effects in Higgs plus jets production

    Rikkert Frederix🇩🇪 · Stefano Frixione🇮🇹 · Eleni Vryonidou🇧🇪 · Marius Wiesemann🇨🇭

    We study the production of a Standard Model Higgs boson in the gluon-fusion channel at the 13 TeV LHC. Our results are accurate to the next-to-leading order in QCD, bar for the lack of some two-loop amplitudes, for up to two extra jets and are matched to the PYTHIA8 Monte Carlo. We address the impact, at the level of inclusive rates and of differential distributions, of the merging of samples characterised by different final-state multiplicities, and of the effects induced by top and bottom masses through heavy-quark loop diagrams. We find that both the merging and the heavy-quark masses must be included in the calculation in order to realistically predict observables of experimental interest.

    hep-phJHEP(2016)·52 citations
18. 18*

    Associated production of electroweak bosons and heavy mesons at LHCb and prospects to observe double parton interactions

    S.P. Baranov🇷🇺 · A.V. Lipatov🇷🇺 · M.A. Malyshev🇷🇺 · A.M. Snigirev🇷🇺 · N.P. Zotov🇷🇺

    The production of weak gauge bosons in association with heavy flavored mesons at the LHCb conditions is considered, and a detailed study of the different contributing processes is presented including single (SPS) and double (DPS) parton scattering mechanisms. We find that the usual DPS factorization formula needs to be corrected for the limited partonic phase space, and that including the relevant corrections reduces discrepancies in the associated $ZD$ production. We conclude finally that double parton scattering dominates the production of same-sign $W^{\pm }{D}^{\pm }$ states, as well as the production of $W^{-}$ bosons associated with $B$-mesons. The latter processes can thus be regarded as new useful DPS indicators.

    hep-phPRD(2016)·10 citations
19. 19*

    Radiative Corrections to the Solar Lepton Mixing Sum Rule

    Jue Zhang🇨🇳 · Shun Zhou🇨🇳

    The simple correlation among three lepton flavor mixing angles $({\theta }_{12}^{},{\theta }_{13}^{},{\theta }_{23}^{})$ and the leptonic Dirac CP-violating phase $\delta$ is conventionally called a sum rule of lepton flavor mixing, which may be derived from a class of neutrino mass models with flavor symmetries. In this paper, we consider the solar lepton mixing sum rule ${\theta }_{12}^{}\approx {\theta }_{12}^{\nu }+{\theta }_{13}^{}\cos \delta$, where ${\theta }_{12}^{\nu }$ stems from a constant mixing pattern in the neutrino sector and takes the value of ${\theta }_{12}^{\nu }=45^{\circ }$ for the bi-maximal mixing (BM), ${\theta }_{12}^{\nu }={\tan }^{-1}(1/\sqrt{2})\approx 35.3^{\circ }$ for the tri-bimaximal mixing (TBM) or ${\theta }_{12}^{\nu }={\tan }^{-1}\left[2/(\sqrt{5}+1)\right]\approx 31.7^{\circ }$ for the golden-ratio mixing (GR), and investigate the renormalization-group (RG) running effects on lepton flavor mixing parameters when this sum rule is assumed at a superhigh-energy scale. For illustration, we work within the framework of the minimal supersymmetric standard model (MSSM), and implement the Bayesian approach to explore the posterior distribution of $\delta$ at the low-energy scale, which becomes quite broad when the RG running effects are significant. Moreover, we also discuss the compatibility of the above three mixing scenarios with current neutrino oscillation data, and observe that radiative corrections can increase such a compatibility for the BM scenario, resulting in a weaker preference for the TBM and GR ones.

    hep-phJHEP(2016)·12 citations
20. 20*

    Comment on "Hybridized Tetraquarks"

    Zhi-Gang Wang🇨🇳

    In this comment, I illustrate that the formula $\Gamma =A\sqrt{\delta }$ suggested in arXiv:1603.07667 comes from a kinematical factor, and has no relation to the existence or non-existence of the $X(5568)$.

    hep-ph1 citation
21. 21*

    On dynamical net-charge fluctuations within a hadron resonance gas approach

    Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬 · L. I. Abou-Salem (Benha U.)🇪🇬 · Asmaa G. Shalaby🇪🇬 · M. Hanafy (Benha U., WLCAPP, Cairo)🇪🇬

    The dynamical net-charge fluctuations (${\nu }_{dyn}$) in different particle ratios $K/\pi$, $K/p$, and $p/\pi$ are calculated from the hadron resonance gas (HRG) model and compared with STAR central Au+Au collisions at $\sqrt{s_{NN}}=7.7-200$GeV and NA49 central Pb+Pb collisions at $\sqrt{s_{NN}}=6.3-17.3$GeV. The three charged-particle ratios ($K/\pi$, $K/p$, and $p/\pi$) are determined as total and average of opposite and average of same charges. We find an excellent agreement between the HRG calculations and the experimental measurements, especially from STAR beam energy scan (BES) program, while the strange particles in the NA49 experiment at lower Super Proton Synchrotron (SPS) energies are not reproduced by the HRG approach. We conclude that the utilized HRG version seems to take into consideration various types of correlations including strong interactions through the heavy resonances and their decays especially at BES energies.

    hep-phhep-thAdv.High Energy Phys.(2016)·6 citations
22. 22*

    Form factor ratio from unpolarized elastic electron proton scattering

    Simone Pacetti🇮🇹 · Egle Tomasi Gustafsson🇫🇷

    A reanalysis of unpolarized electron-proton elastic scattering data is done in terms of the electric to magnetic form factor squared ratio. This observable is in principle more robust against experimental correlations and global normalizations. The present analysis shows indeed that it is a useful quantity that contains reliable and coherent information. The comparison with the ratio extracted from the measurement of the longitudinal to transverse polarization of the recoil proton in polarized electron-proton scattering shows that the results are compatible within the experimental errors. Limits are set on the kinematics where the physical information on the form factors can be safely extracted. The results presented in this work bring a decisive piece of information to the controversy on the deviation of the proton form factors from the dipole dependence.

    ↳ nucl-thhep-phPRC(2016)·12 citations
23. 23*

    The Darkest Hour Before Dawn: Contributions to Cosmic Reionization from Dark Matter Annihilation and Decay

    Hongwan Liu🇺🇸 · Tracy R. Slatyer🇺🇸 · Jesús Zavala🇩🇰

    Dark matter annihilation or decay could have a significant impact on the ionisation and thermal history of the universe. In this paper, we study the potential contribution of dark matter annihilation (s-wave- or p-wave-dominated) or decay to cosmic reionisation, via the production of electrons, positrons and photons. We map out the possible perturbations to the ionisation and thermal histories of the universe due to dark matter processes, over a broad range of velocity-averaged annihilation cross-sections/decay lifetimes and dark matter masses. We have employed recent numerical studies of the efficiency with which annihilation/decay products induce heating and ionization in the intergalactic medium, and in this work extended them down to a redshift of $1+z=4$ for two different reionisation scenarios. We also improve on earlier studies by using the results of detailed structure formation models of dark matter haloes and subhaloes that are consistent with up-to-date $N$-body simulations, with estimates on the uncertainties that originate from the smallest scales. We find that for dark matter models that are consistent with experimental constraints, a contribution of more than 10% to the ionisation fraction at reionisation is disallowed for all annihilation scenarios. Such a contribution is possible only for decays into electron/positron pairs, for light dark matter with mass $m_{\chi }\lesssim$ 100 MeV, and a decay lifetime ${\tau }_{\chi }\sim 10^{24}-10^{25}$ s.

    ↳ astro-ph.COhep-phPRD(2016)·198 citations
24. 24*

    First observation of $\gamma \gamma \to p\bar{p}{K}^{+}{K}^{-}$ and search for exotic baryons in $pK$ systems

    Belle Collaboration: C. P. Shen🇨🇳 · C. Z. Yuan🇨🇳 · I. Adachi🇯🇵 · H. Aihara🇯🇵 · D. M. Asner🇺🇸 · V. Aulchenko🇷🇺 · T. Aushev🇷🇺 · R. Ayad🇸🇦 · V. Babu🇮🇳 · I. Badhrees🇸🇦 · A. M. Bakich🇦🇺 · E. Barberio🇦🇺 and 167 other authors

    The process $\gamma \gamma \to p\bar{p}{K}^{+}{K}^{-}$ and its intermediate processes are measured for the first time using a 980~fb${}^{-1}$ data sample collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The production of $p\bar{p}{K}^{+}{K}^{-}$ and a $\Lambda (1520{)}^0(\bar{\Lambda }(1520{)}^0)$ signal in the $p{K}^{-}$~($\bar{p}{K}^{+}$) invariant mass spectrum are clearly observed. However, no evidence for an exotic baryon near 1540~MeV/$c^2$, denoted as $\Theta (1540{)}^0$~($\bar{\Theta }(1540{)}^0$) or $\Theta (1540{)}^{++}$~($\Theta (1540{)}^{--}$), is seen in the $p{K}^{-}$~($\bar{p}{K}^{+}$) or $p{K}^{+}$~($\bar{p}{K}^{-}$) invariant mass spectra. Cross sections for $\gamma \gamma \to p\bar{p}{K}^{+}{K}^{-}$, $\Lambda (1520{)}^0\bar{p}{K}^{+}+c.c.$ and the products $\sigma (\gamma \gamma \to \Theta (1540{)}^0\bar{p}{K}^{+}+c.c.)\text{BR}(\Theta (1540{)}^0\to p{K}^{-})$ and $\sigma (\gamma \gamma \to \Theta (1540{)}^{++}\bar{p}{K}^{-}+c.c.)\text{BR}(\Theta (1540{)}^{++}\to p{K}^{+})$ are measured. We also determine upper limits on the products of the ${\chi }_{c0}$ and ${\chi }_{c2}$ two-photon decay widths and their branching fractions to $p\bar{p}{K}^{+}{K}^{-}$ at the 90\% credibility level.

    ↳ hep-exhep-phPRD(2016)·7 citations
25. 25*

    Low-energy theorems for nucleon-nucleon scattering at $M_{\pi }=450$ MeV

    V. Baru🇩🇪 · E. Epelbaum🇩🇪 · A. A. Filin🇩🇪

    We apply the low-energy theorems to analyze the recent lattice QCD results for the two-nucleon system at a pion mass of $M_{\pi }\simeq 450$ MeV obtained by the NPLQCD collaboration. We find that the binding energies of the deuteron and dineutron are inconsistent with the low-energy behavior of the corresponding phase shifts within the quoted uncertainties and vice versa. Using the binding energies of the deuteron and dineutron as input, we employ the low-energy theorems to predict the phase shifts and extract the scattering length and the effective range in the ${}^3{S}_1$ and ${}^1{S}_0$ channels. Our results for these quantities are consistent with those obtained by the NPLQCD collaboration from effective field theory analyses but are in conflict with their determination based on the effective-range approximation.

    ↳ nucl-thhep-lathep-phPRC(2016)·31 citations
26. 26*

    Testing Einstein's Equivalence Principle with Supercluster Laniakea's Gravitational Field

    Zhi-Xing Luo🇨🇳 · Bo Zhang🇨🇳 · Jun-Jie Wei🇨🇳 · Xue-Feng Wu🇨🇳

    Comparing the parameterized post-Newtonian parameter $\gamma$ values for different types of particles, or the same type of particles with different energies is an important method to test the Einstein Equivalence Principle (EEP). Assuming that the observed time delays are dominated by the gravitational potential of the Laniakea supercluster of galaxies, better results of EEP constraints can be obtained. In this paper, we apply photons from three kinds of cosmic transients, including TeV blazars, gamma-ray bursts as well as fast radio bursts to constrain EEP. With a gravitational field far more stronger than a single galaxy, we obtain 4--5 orders of magnitude more stringent than the pervious results.

    ↳ astro-ph.HEgr-qchep-phJHEAp·6 citations
27. 27*

    Relativistic Kinematics

    Raghunath Sahoo🇮🇳

    This lecture note covers Relativistic Kinematics, which is very useful for the beginners in the field of high-energy physics. A very practical approach has been taken, which answers "why and how" of the kinematics useful for students working in the related areas.

    ↳ nucl-exhep-exhep-phnucl-thLect.Notes Phys.(2025)·19 citations
28. 28*

    In Search of a Pristine Signal for (Scale-)Chiral Symmetry in Nuclei

    Mannque Rho🇫🇷

    I describe the long-standing search for a "smoking-gun" signal for the manifestation of (scale-)chiral symmetry in nuclear interactions. It is prompted by Gerry Brown's last unpublished note, reproduced verbatim below, on the preeminent role of pions and vector ($\rho$,$\omega$) mesons in providing a simple and elegant description of strongly correlated nuclear interactions. In this note written in tribute to Gerry Brown, I first describe a case of an unambiguous signal in axial-charge transitions in nuclei and then combine his ideas with the more recent development on the role of hidden symmetries in nuclear physics. What transpires is the surprising conclusion that the Landau-Migdal fixed point interaction $G_0^{\prime }$, the nuclear tensor forces and Brown-Rho scaling, all encoded in scale-invariant hidden local symmetry, as Gerry put, "run the show and make all forces equal."

    ↳ nucl-thhep-phIJMPE(2017)·8 citations
29. 29*

    The $a_0(980)$ and $\Lambda (1670)$ in the ${\Lambda }_c^{+}\to {\pi }^{+}\eta \Lambda$ decay

    Ju-Jun Xie🇨🇳 · Li-Sheng Geng🇨🇳

    We propose to study the $a_0(980)$ and the $\Lambda (1670)$ resonances in the ${\Lambda }_c^{+}\to {\pi }^{+}\eta \Lambda$ decay via the final state interactions of the ${\pi }^{+}\eta$ and $\eta \Lambda$ pairs. The weak interaction part proceeds through the $c$ quark decay process: $c(ud)\to (s+u+\bar{d})(ud)$, while the hadronization part takes place in two different mechanisms. In the first mechanism, the $sud$ cluster picks up a $q\bar{q}$ pair from the vacuum to form the $\eta \Lambda$ meson-baryon pair while the $u\bar{d}$ pair from the weak decay hadronizes into a ${\pi }^{+}$. In the second, the $sud$ cluster turns into a $\Lambda$, while the $u\bar{d}$ pair from the $c$ decay picks up a $q\bar{q}$ pair and hadronizes into a meson-meson pair ($\pi \eta$ or $K\bar{K}$). Because the final ${\pi }^{+}\eta$ and $\eta \Lambda$ states are in pure isospin $I=1$ and $I=0$ combinations, the ${\Lambda }_c^{+}\to {\pi }^{+}\eta \Lambda$ decay can be an ideal process to study the $a_0(980)$ and $\Lambda (1670)$ resonances. Describing the final state interaction in the chiral unitary approach, we find that the ${\pi }^{+}\eta$ and $\eta \Lambda$ invariant mass distributions, up to an arbitrary normalization, show clear cusp and peak structures, which can be associated with the $a_0(980)$ and $\Lambda (1670)$ resonances, respectively. The proposed mechanism can provide valuable information on the nature of these resonances and can in principle be test by facilities such as BEPCII.

    ↳ nucl-thhep-phEPJC(2016)·43 citations
30. 30*

    Higher Order Cumulants in Colorless Partonic Plasma

    S. Cherif🇩🇿 · M. A. A. Ahmed🇸🇦 · M. Ladrem🇸🇦

    Any physical system considered to study the QCD deconfinement phase transition certainly has a finite volume, so the finite size effects are inevitably present. This renders the location of the phase transition and the determination of its order as an extremely difficult task, even in the simplest known cases. In order to identify and locate the colorless QCD deconfinement transition point in finite volume $T_0(V)$, a new approach based on the finite-size cumulant expansion of the order parameter and the ${\mathcal{L}}_{m,n}$-Method is used.We have shown that both cumulants of higher order and their ratios, associated to the thermodynamical fluctuations of the order parameter, in QCD deconfinement phase transition behave in a particular enough way revealing pronounced oscillations in the transition region. The sign structure and the oscillatory behavior of these in the vicinity of the deconfinement phase transition point might be a sensitive probe and may allow one to elucidate their relation to the QCD phase transition point. In the context of our model, we have shown that the finite volume transition point is always associated to the appearance of a particular point in whole higher order cumulants under consideration.

    ↳ hep-thhep-phAIP Conf.Proc.(2016)·1 citation
31. 31*

    A new method of creating high intensity neutron source

    T. Masuda🇯🇵 · A. Yoshimi🇯🇵 · M. Yoshimura🇯🇵

    We propose a new scheme of producing intense neutron beam whose yields exceed those of existing facilities by many orders of magnitude. This scheme uses the recently proposed photon beam extracted from circulating quantum ions, which is directed to a deuteron target for photo-disintegration. The calculated neutron energy spectrum is nearly flat down to neV range, except a threshold rise and its adjacent wide structure. Hence, there exists a possibility of directly using sub-eV neutrons without a moderator. We shall have brief comments on promising particle physics applications using this large yield of neutron.

    ↳ nucl-exhep-exhep-phphysics.acc-ph+1IJMPE(2017)·0 citations
32. 32*

    Flavour dependence of the pion and kaon form factors and parton distribution functions

    Parada T. P. Hutauruk🇦🇺 · Ian C. Cloet🇺🇸 · Anthony W. Thomas🇦🇺

    The separate quark flavour contributions to the pion and kaon valence quark distribution functions are studied, along with the corresponding electromagnetic form factors in the space-like region. The calculations are made using the solution of the Bethe-Salpeter equation for the model of Nambu and Jona-Lasinio with proper-time regularization. Both the pion and kaon form factors and the valence quark distribution functions reproduce many of the features of the available empirical data. The larger mass if the strange quark naturally explains the empirical fact that the ratio $u_{K^{+}}(x)/u_{{\pi }^{+}}(x)$ drops below unity at large $x$, with a value of approximately $M_u^2/M_s^2$ as $x\to 1$. With regard to the elastic form factors we report a large flavour dependence, with the $u$-quark contribution to the kaon form factor being an order of magnitude smaller than that of the $s$-quark at large $Q^2$, which may be a sensitive measure of confinement effects in QCD. Surprisingly though, the total $K^{+}$ and ${\pi }^{+}$ form factors differ by only 10\%.

    ↳ nucl-thhep-phPRC(2016)·86 citations
33. 33*

    Density distributions in the $B$ meson

    Benoît Blossier🇫🇷 · Antoine Gérardin🇩🇪

    We report on a two-flavor lattice QCD study of the axial, charge and matter distributions of the $B$ meson and its first radial excitation. As our framework is the static limit of Heavy Quark Effective Theory (HQET), taking their Fourier transform gives access to several form factors at the kinematical point $q^2=0$. Moreover they provide some useful information on the nature of an excited state, i.e. a radial excitation of a quark-antiquark bound state or a multihadron state.

    ↳ hep-lathep-phPRD(2016)·8 citations
34. 34*

    Study of the Pion-Nucleon Coupling Constant Charge Dependence on the Basis of the Low-Energy Data on Nucleon-Nucleon Interaction

    V. A. Babenko🇺🇦 · N. M. Petrov🇺🇦

    We study relationship between the physical quantities that characterize pion-nucleon and nucleon-nucleon interaction on the basis of the fact that nuclear forces in the nucleon-nucleon system at low energies are mainly determined by the one-pion exchange mechanism. By making use of the recommended proton-proton low-energy scattering parameters, we obtain the following value for the charged pion-nucleon coupling constant g${}_{{\pi }^{\pm }}^2/4\pi =14.55(13)$. Calculated value of this quantity is in excellent agreement with the experimental result g${}_{{\pi }^{\pm }}^2/4\pi =14.52(26)$ of the Uppsala Neutron Research Group. At the same time, the obtained value of the charged pion-nucleon coupling constant differs markedly from the value of the neutral pion-nucleon coupling constant g${}_{{\pi }^0}^2/4\pi =13.55(13)$. Thus, our results show considerable charge splitting of the pion-nucleon coupling constant.

    ↳ nucl-thhep-ph8 citations
35. 35*

    Interplay between sign problem and Z_3 symmetry in three-dimensional Potts model

    Takehiro Hirakida🇯🇵 · Hiroaki Kouno🇯🇵 · Junichi Takahashi🇯🇵 · Masanobu Yahiro🇯🇵

    We construct four kinds of Z3-symmetric three-dimentional (3-d) Potts models, each with different number of states at each site on a 3-d lattice, by extending the 3-d three-state Potts model. Comparing the ordinary Potts model with the four Z3-symmetric Potts models, we investigate how Z3 symmetry affects the sign problem and see how the deconfinement transition line changes in the $\mu -\kappa$ plane as the number of states increases, where $\mu$ $(\kappa )$ plays a role of chemical potential (temperature) in the models. We find that the sign problem is almost cured by imposing Z3 symmetry. This mechanism may happen in Z3-symmetric QCD-like theory. We also show that the deconfinement transition line has stronger $\mu$-dependence with respect to increasing the number of states.

    ↳ hep-lathep-phhep-thPRD(2016)·15 citations
36. 36*

    Modular invariant inflation

    Tatsuo Kobayashi🇯🇵 · Daisuke Nitta🇯🇵 · Yuko Urakawa🇯🇵

    Modular invariance is a striking symmetry in string theory, which may keep stringy corrections under control. In this paper, we investigate a phenomenological consequence of the modular invariance, assuming that this symmetry is preserved as well as in a four dimensional (4D) low energy effective field theory. As a concrete setup, we consider a modulus field $T$ whose contribution in the 4D effective field theory remains invariant under the modular transformation and study inflation drived by $T$. The modular invariance restricts a possible form of the scalar potenntial. As a result, large field models of inflation are hardly realized. Meanwhile, a small field model of inflation can be still accomodated in this restricted setup. The scalar potential traced during the slow-roll inflation mimics the hilltop potential $V_{ht}$, but it also has a non-negligible deviation from $V_{ht}$. Detecting the primordial gravitational waves predicted in this model is rather challenging. Yet, we argue that it may be still possible to falsify this model by combining the information in the reheating process which can be determined self-completely in this setup.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2016)·31 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.