Tue·Jun 20, 2017Tuesday·June 20, 2017

1. 01*

   Towards an effective field theory approach to the neutrinoless double-beta decay

   Mihai Horoi🇺🇸 · Andrei Neacsu🇺🇸

   Weak interaction in nuclei represents a well-known venue for testing many of the fundamental symmetries of the Standard Model. In particular, neutrinoless double-beta decay offers the possibility to test Beyond Standard Model theories predicting that neutrinos are Majorana fermions and the lepton number conservation is violated. This paper focuses on an effective field theory approach to neutrinoless double-beta decay for extracting information regarding the properties of the Beyond Standard Model Lagrangian responsible for this process. We use shell model nuclear matrix elements and the latest experimental lower limits for the half-lives to extract the lepton number violating parameters of five nuclei of experimental interest, and lower limits for the energy scales of the new physics.

   hep-phnucl-th36 citations
2. 02*

   Photo- and electroproduction of $\Lambda (1405)$ via ${\gamma }^{(\ast )}p\to K^{+}{\pi }^{+}{\Sigma }^{-}$

   Seung-il Nam🇰🇷

   In this work, we perform a \textit{toy-model} analysis for the unpolarized photo- and electroproduction of $\Lambda (1405)\equiv {\Lambda }^{\ast }$ via ${\gamma }^{(\ast )}p\to K^{+}{\pi }^{+}{\Sigma }^{-}$ by employing the effective Lagrangian approach at the tree level only. We consider that ${\Lambda }^{\ast }$ consists of the high-mass ($H$) and low-mass ($L$) poles as suggested by the chiral unitary model (ChUM). We determine all the model parameters including coupling constants and cutoff parameters for the phenomenological strong form factors by using the theoretical information from ChUM and available experimental data. The electromagnetic (EM) form factors for the two poles are parameterized appropriately being similar to that for the neutron by employing the ChUM estimates for the EM root-mean-squared (rms) radii for the two poles. We observe from the numerical calculations that, for the photoproduction of ${\Lambda }^{\ast }$, the interference between the two poles turns out to be destructive, resulting in the single-peak line at $M_{{\pi }^{+}{\Sigma }^{-}}\approx 1405$ MeV in the invariant-mass distribution. On the contrary, there appear two peaks in the distribution for the electroproduction as observed in the CLAS/Jlab electroproduction data, due to the constructive interference, which is mainly caused by the Dirac form factors for the two poles. From this observation, we conclude that, in order to explain the photo- and electroproduction data simultaneously, i.e., \textit{single} and \textit{double} peaks, respectively, in the invariant-mass distribution, the interference patterns for the two poles should follow those suggested by ChUM. In turn, it is a strong theoretical and experimental supports for the two-pole structure scenario for ${\Lambda }^{\ast }$.

   hep-phnucl-thPRD(2017)·9 citations
3. 03*

   Effective Theory of Flavor for Minimal Mirror Twin Higgs

   Riccardo Barbieri🇮🇹 · Lawrence J. Hall🇺🇸 · Keisuke Harigaya🇺🇸

   We consider two copies of the Standard Model, interchanged by an exact parity symmetry, P. The observed fermion mass hierarchy is described by suppression factors ${ϵ}^{n_i}$ for charged fermion $i$, as can arise in Froggatt-Nielsen and extra-dimensional theories of flavor. The corresponding flavor factors in the mirror sector are ${ϵ}^{\prime n_i}$, so that spontaneous breaking of the parity P arises from a single parameter ${ϵ}^{\prime }/ϵ$, yielding a tightly constrained version of Minimal Mirror Twin Higgs, introduced in our previous paper. Models are studied for simple values of $n_i$, including in particular one with SU(5)-compatibility, that describe the observed fermion mass hierarchy. The entire mirror quark and charged lepton spectrum is broadly predicted in terms of ${ϵ}^{\prime }/ϵ$, as are the mirror QCD scale and the decoupling temperature between the two sectors. Helium-, hydrogen- and neutron-like mirror dark matter candidates are constrained by self-scattering and relic ionization. In each case, the allowed parameter space can be fully probed by proposed direct detection experiments. Correlated predictions are made as well for the Higgs signal strength and the amount of dark radiation.

   hep-phJHEP(2017)·43 citations
4. 04*

   Extra lepton pair emission corrections to Drell-Yan processes in PHOTOS and SANC

   S. Antropov (1)🇵🇱 · A. Arbuzov (2 and 3)🇷🇺 · R. Sadykov (4)🇷🇺 · Z. Was (1 and 5) ((1) Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, (2) Bogoliubov Laboratory for Theoretical Physics, JINR, Dubna, (3) Dubna State University, Dubna, (4) Dzhelepov Laboratory of Nuclear Problems, JINR, Dubna, (5) Theory Group, Physics Department, CERN, Geneva)🇵🇱

   In the paper we present results for final state emissions of lepton pairs in decays of heavy intermediate states such as Z boson. Short presentations of PHOTOS and SANC algorithms and physics assumptions are given. Numerical distributions of relevance for LHC observables are shown. They are used in discussions of systematic errors in the predictions of pair emissions as implemented in the two programs. Suggestions for the future works are given. Present results confirm, that for the precision of 0.3% level, in simulation of final state the pair emissions can be avoided. For the precision of 0.1-0.2%, the results obtained with the presented programs should be enough. To cross precision tag of 0.1%, the further work is however required.

   hep-phActa Phys.Polon.B(2017)·13 citations
5. 05*

   Hidden Charged Dark Matter and Chiral Dark Radiation

   P. Ko🇰🇷 · Natsumi Nagata🇯🇵 · Yong Tang🇯🇵

   In the light of recent possible tensions in the Hubble constant $H_0$ and the structure growth rate ${\sigma }_8$ between the Planck and other measurements, we investigate a hidden-charged dark matter (DM) model where DM interacts with hidden chiral fermions, which are charged under the hidden SU(N) and U(1) gauge interactions. The symmetries in this model assure these fermions to be massless. The DM in this model, which is a Dirac fermion and singlet under the hidden SU(N), is also assumed to be charged under the U(1) gauge symmetry, through which it can interact with the chiral fermions. Below the confinement scale of SU(N), the hidden quark condensate spontaneously breaks the U(1) gauge symmetry such that there remains a discrete symmetry, which accounts for the stability of DM. This condensate also breaks a flavor symmetry in this model and Nambu-Goldstone bosons associated with this flavor symmetry appear below the confinement scale. The hidden U(1) gauge boson and hidden quarks/Nambu-Goldstone bosons are components of dark radiation (DR) above/below the confinement scale. These light fields increase the effective number of neutrinos by $\delta N_{\mathrm{eff}}\simeq 0.59$ above the confinement scale for $N=2$, resolving the tension in the measurements of the Hubble constant by Planck and Hubble Space Telescope if the confinement scale is $\lesssim 1$ eV. DM and DR continuously scatter with each other via the hidden U(1) gauge interaction, which suppresses the matter power spectrum and results in a smaller structure growth rate. The DM sector couples to the Standard Model sector through the exchange of a real singlet scalar mixing with the Higgs boson, which makes it possible to probe our model in DM direct detection experiments. Variants of this model are also discussed, which may offer alternative ways to investigate this scenario.

   hep-phastro-ph.COPLB(2017)·56 citations
6. 06*

   Erratum: Numerical values of the $f^F,f^D$ and $f^S$ coupling constants in SU(3) invariant Lagrangian of the interaction of the vector-meson nonets with $1/2^{+}$ octet baryons [Phys. Rev. C93, 055208 (2016)]

   Cyril Adamuščin🇸🇰 · Erik Bartoš🇸🇰 · Stanislav Dubnička🇸🇰 · Anna Z. Dubničková🇸🇰

   It is clearly demonstrated that numerical values of the $f^F,f^D$ and $f^S$ coupling constants in SU(3) invariant Lagrangian of the interaction of the vector-meson nonets with $1/2^{+}$ octet baryons do not depend on the chosen version of the $\omega -\varphi$ mixing.

   hep-phPRC(2016)·18 citations
7. 07*

   Subleading power corrections to the pion-photon transition form factor in QCD

   Yu-Ming Wang🇨🇳 · Yue-Long Shen🇨🇳

   We reconsider QCD factorization for the leading power contribution to the ${\gamma }^{\ast }\gamma \to {\pi }^0$ form factor $F_{{\gamma }^{\ast }\gamma \to {\pi }^0}(Q^2)$ at one loop using the evanescent operator approach, and demonstrate the equivalence of the resulting factorization formulae derived with distinct prescriptions of ${\gamma }_5$ in dimensional regularization. Applying the light-cone QCD sum rules (LCSRs) with photon distribution amplitudes (DAs) we further compute the subleading power contribution to the pion-photon form factor induced by the "hadronic" component of the real photon at the next-to-leading-order in $\mathcal{O}({\alpha }_s)$, with both naive dimensional regularization and 't Hooft-Veltman schemes of ${\gamma }_5$. Confronting our theoretical predictions of $F_{{\gamma }^{\ast }\gamma \to {\pi }^0}(Q^2)$ with the experimental measurements from the BaBar and the Belle Collaborations implies that a reasonable agreement can be achieved without introducing an "exotic" end-point behaviour for the twist-2 pion DA.

   hep-phhep-exhep-latJHEP(2017)·43 citations
8. 08*

   Analytic parametrizations of the ${\gamma }^{\ast }N\to N(1440)$ form factors inspired by Light-Front holography

   G. Ramalho🇧🇷

   We present analytic parametrizations for the ${\gamma }^{\ast }N\to N(1440)$ form factors derived from light-front holography in leading twist approximation. The new parametrizations describe the electromagnetic form factors using analytic functions dependent on the masses of the $\rho$ meson and respective radial excitations, as well as the masses of the nucleon and the resonance $N(1440)$. The free parameters of the model, associated with three independent couplings, are interpreted as bare couplings, and are fixed by the nucleon data for large $Q^2$. The proposed parametrizations compare remarkably well with the empirical data for $Q^2>2$ GeV${}^2$, corroborating the dominant role of the valence quark degrees of freedom in the ${\gamma }^{\ast }N\to N(1440)$ transition.

   hep-phhep-exnucl-exnucl-thPRD(2017)·19 citations
9. 09*

   Color screening in flux tubes and in the color Coulomb potential from the QCD Field Correlators

   M.S. Lukashov🇷🇺 · Yu.A. Simonov🇷🇺

   Colorelectric and Colormagnetic structure of the flux tubes, connecting heavy quark and antiquark, is investigated in the framework of the Field Correlator method which describes all resulting fields in terms of correlators $D^E$ and $D_1^E$. The latter have been computed via gluelumps, which allows to predict the resulting distribution of color fields $\mathbf{E}(\mathbf{r}),$ and colormagnetic currents $\mathbf{k}(\mathbf{r})$ in the flux tubes. It is shown, that at large distances $r\gg \lambda \approx 0.2$ fm the whole structure of fields and relations between them is similar to that of the dual superconductor theory, but the basic dynamics, including small distances, is given by field correlators of the real stochastic vacuum. The important contradiction between the strong screening of color fields in the width of flux tubes and almost no screening in the perturbative $Q\bar{Q}$ potential is resolved.

   hep-phhep-latPRD(2017)·3 citations
10. 10*

    Probing decaying heavy dark matter with the 4-year IceCube HESE data

    Atri Bhattacharya (Université de Liège)🇧🇪 · Arman Esmaili (Pontifícia Universidade Católica do Rio de Janeiro)🇧🇷 · Sergio Palomares-Ruiz (Valencia U., IFIC)🇪🇸 · Ina Sarcevic (University of Arizona)🇺🇸

    After the first four years of data taking, the IceCube neutrino telescope has observed 54 high-energy starting events (HESE) with deposited energies between 20 TeV and 2 PeV. The background from atmospheric muons and neutrinos is expected to be of about 20 events, all below 100 TeV, thus pointing towards the astrophysical origin of about 8 events per year in that data set. However, their precise origin remains unknown. Here, we perform a detailed analysis of this event sample (considering simultaneously the energy, hemisphere and topology of the events) by assuming two contributions for the signal events: an isotropic power-law flux and a flux from decaying heavy dark matter. We fit the mass and lifetime of the dark matter and the normalization and spectral index of an isotropic power-law flux, for various decay channels of dark matter. We find that a significant contribution from dark matter decay is always slightly favored, either to explain the excess below 100 TeV, as in the case of decays to quarks or, as in the case of neutrino channels, to explain the three multi-PeV events. Also, we consider the possibility to interpret all the data by dark matter decays only, considering various combinations of two decay channels. We show that the decaying dark matter scenario provides a better fit to HESE data than the isotropic power-law flux.

    hep-phastro-ph.HEhep-exJCAP(2017)·50 citations
11. 11*

    Violation of Positivity Bounds in Models of Generalized Parton Distributions

    Brian C. Tiburzi🇺🇸 · Gaurav Verma🇺🇸

    As with parton distributions, flexible phenomenological parameterizations of generalized parton distributions (GPDs) are essential for their extraction from data. The large number of constraints imposed on GPDs make simple Lorentz covariant models viable; but, such models are often incomplete in that they employ the impulse approximation. Using the GPD of the pion as a test case, we show that the impulse approximation can lead to violation of the positivity bound required of GPDs. We focus on a particular model of the pion bound-state vertex that was recently proposed and demonstrate that satisfying the bound is not guaranteed by Lorentz covariance. Violation of the positivity bound is tied to a problematic mismatch between the behavior of the quark distribution at the endpoint and the crossover value of the GPD.

    hep-phnucl-thPRD(2017)·3 citations
12. 12*

    On the hadron mass decomposition

    Cédric Lorcé (Ecole polytechnique, CPHT)🇫🇷

    We argue that the standard decompositions of the hadron mass overlook pressure effects, and hence should be interpreted with great care. Based on the semiclassical picture, we propose a new decomposition that properly accounts for these pressure effects. Because of Lorentz covariance, we stress that the hadron mass decomposition automatically comes along with a stability constraint, which we discuss for the first time. We show also that if a hadron is seen as made of quarks and gluons, one cannot decompose its mass into more than two contributions without running into trouble with the consistency of the physical interpretation. In particular, the so-called quark mass and trace anomaly contributions appear to be purely conventional. Based on the current phenomenological values, we find that in average quarks exert a repulsive force inside nucleons, balanced exactly by the gluon attractive force.

    hep-phhep-latnucl-thEPJC(2018)·141 citations
13. 13*

    Towards a Next-to-Next-to-Leading Order analysis of matching in $B^0$-${\bar{B}}^0$ mixing

    Andrey G. Grozin🇷🇺 · Thomas Mannel🇩🇪 · Alexei A. Pivovarov🇩🇪

    We compute perturbative corrections to matching coefficients of QCD to HQET for the matrix element of the $\Delta B=2$ operator that determines the mass difference in $B^0-{\bar{B}}^0$ system of states. This involves the technical point of choosing the operator basis in HQET, separating physical operators from evanescent ones. We obtain an analytical result for some of the two-loop corrections at order ${\alpha }_s^2$.

    hep-phPRD(2017)·24 citations
14. 14*

    LHC Search of New Higgs Boson via Resonant Di-Higgs Production with Decays into 4W

    Jing Ren🇨🇦 · Rui-Qing Xiao🇨🇳 · Maosen Zhou🇨🇳 · Yaquan Fang🇨🇳 · Hong-Jian He🇨🇳 · Weiming Yao🇺🇸

    Searching for new Higgs particle beyond the observed light Higgs boson h(125GeV) will unambiguously point to new physics beyond the standard model. We study the resonant production of a CP-even heavy Higgs state $H^0$ in the di-Higgs channel via, $gg\to H^0\to h^0{h}^0\to W{W}^{\ast }W{W}^{\ast }$, at the LHC Run-2 and the high luminosity LHC (HL-LHC). We analyze two types of the $4W$ decay modes, one with the same-sign di-leptons ($4W\to {\ell }^{\pm }\nu {\ell }^{\pm }\nu 4q$) and the other with tri-leptons ($4W\to {\ell }^{\pm }\nu {\ell }^{\mp }\nu {\ell }^{\pm }\nu 2q$). We perform a full simulation for the signals and backgrounds, and estimate the discovery potential of the heavy Higgs state at the LHC Run-2 and the HL-LHC, in the context of generical two-Higgs-doublet models (2HDM). We determine the viable parameter space of the 2HDM as allowed by the theoretical constraints and the current experimental limits. We systematically analyze the allowed parameter space of the 2HDM which can be effectively probed by the heavy Higgs searches of the LHC, and further compare this with the viable parameter region under the current theoretical and experimental bounds.

    hep-phhep-exJHEP(2018)·40 citations
15. 15*

    Sterile neutrino searches via displaced vertices at LHCb

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

    We explore the sensitivity of displaced vertex searches at LHCb for testing sterile neutrino extensions of the Standard Model towards explaining the observed neutrino masses. We derive estimates for the constraints on sterile neutrino parameters from a recently published displaced vertex search at LHCb based on run 1 data. They yield the currently most stringent limit on active-sterile neutrino mixing in the sterile neutrino mass range between 4.5 GeV and 10 GeV. Furthermore, we present forecasts for the sensitivities that could be obtained from the run 2 data and also for the high-luminosity phase of the LHC.

    hep-phPLB(2017)·105 citations
16. 16*

    Narrow exotic tetraquark mesons in large-$N_c$ QCD

    Wolfgang Lucha🇦🇹 · Dmitri Melikhov🇦🇹 · Hagop Sazdjian🇫🇷

    Discussing four-point Green functions of bilinear quark currents in large-$N_c$ QCD, we formulate rigorous criteria for selecting diagrams appropriate for the analysis of potential tetraquark poles. We find that both flavor-exotic and cryptoexotic (i.e., flavor-nonexotic) tetraquarks, if such poles exist, have a width of order $O(1/N_c^2)$, so they are parametrically narrower compared to the ordinary $\bar{q}q$ mesons, which have a width of order $O(1/N_c)$. Moreover, for flavor-exotic states, the consistency of the large-$N_c$ behavior of "direct" and "recombination" Green functions requires two narrow flavor-exotic states, each coupling dominantly to one specific meson-meson channel.

    hep-phPRD(2017)·36 citations
17. 17*

    Dark matter and electroweak phase transition in the mixed scalar dark matter model

    Xuewen Liu🇨🇳 · Ligong Bian🇨🇳

    We study the electroweak phase transition in the framework of scalar singlet-doublet mixed dark matter model, where the particle dark matter candidate is the lightest neutral Higgs that comprised of the CP-even component of inert doublet and a singlet scalar. The dark matter can be dominated by the inert doublet or singlet scalar depending on the mixing. We present several benchmark models to investigate the two situations after imposing several theoretical and experimental constraints. An additional singlet scalar and the inert doublet drive the electroweak phase transition to be strongly first order. A strong first order electroweak phase transition and a viable dark matter candidate can be accomplished in two benchmark models simultaneously, where a proper mass splitting among the neutral and charged Higgs masses is needed.

    hep-phPRD(2018)·18 citations
18. 18*

    Radiative energy loss of neighboring subjets

    Yacine Mehtar-Tani🇺🇸 · Konrad Tywoniuk🇨🇭

    We compute the in-medium energy loss probability distribution of two neighboring subjets at leading order, in the large-$N_c$ approximation. Our result exhibits a gradual onset of color decoherence of the system and accounts for two expected limiting cases. When the angular separation is smaller than the characteristic angle for medium-induced radiation, the two-pronged substructure lose energy coherently as a single color charge, namely that of the parent parton. At large angular separation the two subjets lose energy independently. Our result is a first step towards quantifying effects of energy loss as a result of the fluctuation of the multi-parton jet substructure and therefore goes beyond the standard approach to jet quenching based on single parton energy loss. We briefly discuss applications to jet observables in heavy-ion collisions.

    hep-phnucl-thNPA(2018)·58 citations
19. 19*

    Flavourful $Z^{\prime }$ models for $R_{K^{(\ast )}}$

    Stephen F. King🇬🇧

    We show how any flavour conserving $Z^{\prime }$ model can be made flavour violating and non-universal by introducing mass mixing of quarks and leptons with a fourth family of vector-like fermions with non-universal $Z^{\prime }$ couplings. After developing a general formalism, we focus on two concrete examples, namely a fermiophobic model, and an $SO(10)$ GUT model, and show how they can account for the anomalous $B$ decay ratios $R_K$ and $R_{K^{\ast }}$. A similar analysis could be performed for $B-L$ models, $E_6$ models, composite models, and so on.

    hep-phJHEP(2017)·88 citations
20. 20*

    The study of the properties of the extended Higgs boson sector within hMSSM model

    T.V. Obikhod🇺🇦 · E.A. Petrenko🇺🇦

    Using the latest experimental data, performed by ATLAS Collaboration and within the framework of the Minimal Supersymmetric Standard Model, we presented the calculations for cross sections times branching fractions, $\sigma \times Br$, as a functions of the CP-even, H, Higgs boson mass, CP-odd, A, Higgs boson mass and charged, H${}^{\pm }$, Higgs boson mass. Using the restricted parameter set, received from the hMSSM+HDECAY and "low-tb-high" scenarios, with the help of the computer programs SOFTSUSY, Prospino and SusHi, we received the large values of $\sigma \times Br$ for A and H bosons at tan$\beta$=2 for the planned 14 TeV at the LHC and found the large $\sigma \times Br$ at tan$\beta$=30 for charged Higgs boson. The obtained results are of experimental interest as they are connected with the experimental searches for new physics beyond the Standard Model at the LHC.

    hep-phProb.Atomic Sci.Technol.·1 citation
21. 21*

    Decuplet to octet baryon transitions in chiral perturbation theory

    Hao-Song Li🇨🇳 · Zhan-Wei Liu🇨🇳 · Xiao-Lin Chen🇨🇳 · Wei-Zhen Deng🇨🇳 · Shi-Lin Zhu🇨🇳

    We have systematically investigated the decuplet (T) to octet (B) baryon ($T\to B\gamma$) transition magnetic moments to the next-to-next-to-leading order and electric quadruple moments to the next-to-leading order in the framework of the heavy baryon chiral perturbation theory. Our calculation includes the contributions from both the intermediate decuplet and octet baryon states in the loops. Our results show reasonably good convergence of the chiral expansion and agreement with the experimental data. The analytical expressions may be useful to the chiral extrapolation of the lattice simulations of the decuplet electromagnetic properties.

    hep-phhep-exhep-latnucl-ex+1EPJC(2019)·19 citations
22. 22*

    Prospects for the Mass Ordering (MO) and ${\theta }_{23}$-Octant sensitivity in LBL experiments: UNO, DUNE \& NO$\nu$A

    Mandip Singh🇮🇳

    This article represents quantitative numerical analysis to find the sensitivity for the mass ordering and octant of atmospheric mixing angle ${\theta }_{23}$ within 3$\sigma$ range of oscillation parameters, in the context of three long base line (LBL) accelerator experiments viz. UNO, DUNE and NO$\nu$A. We notice that on the basis of quantitative sensitivity pertaining to the event rate, it is possible to investigate the mass ordering within all experiments. Conclusively, like NO$\nu$A and DUNE experiments, UNO experiment stands as better alternative for investigating mass ordering, especially when we need to cross check the results at higher beam energies and base line lengths. We observe that discrete solutions viz. {\it wrong octant-right ${\delta }_{CP}$, wrong octant-wrong ${\delta }_{CP}$} and {\it right octant-wrong ${\delta }_{CP}$} and continuous solutions arising due to submergence of discrete solutions with true solution are possible up to 3$\sigma$ level. It is UNO experiment that alone have the potential to remove these discrete solutions, while both NO$\nu$A and DUNE experiments have very poor tendency to remove these discrete solutions especially near the maximal mixing. We find that these discrete solutions can be resolved up to 3$\sigma$ level by the combined NO$\nu$A+DUNE+UNO data set, at all multiple degenerate solutions in the true parameter space considered under the study. Though replacing half the neutrino run with antineutrino run introduces qualitative advantage because of their different dependences on ${\delta }_{CP}$, but due to lower cross section and reduction in the statistics, addition of antineutrino data make the precision worse. Thus considering experimental data only in the neutrino mode, enhances ${\delta }_{CP}$ and ${\theta }_{23}$ precision significantly.

    hep-ph2 citations
23. 23*

    Acceleration by Strong Interactions

    Martin Erdmann🇩🇪 · Christian Glaser🇩🇪 · Thorben Quast🇩🇪

    Beyond the attractive strong potential needed for hadronic bound states, strong interactions are predicted to provide repulsive forces depending on the color charges involved. The repulsive interactions could in principle serve for particle acceleration with highest gradients in the order of GeV/fm. Indirect evidence for repulsive interactions have been reported in the context of heavy meson production at colliders. In this contribution, we sketch a thought experiment to directly investigate repulsive strong interactions. For this we prepare two quarks using two simultaneous deep inelastic scattering processes off an iron target. We discuss the principle setup of the experiment and estimate the number of electrons on target required to observe a repulsive effect between the quarks.

    hep-phhep-ex0 citations
24. 24*

    Constraining Neutrino Masses, the Cosmological Constant and BSM Physics from the Weak Gravity Conjecture

    Luis E. Ibanez🇪🇸 · Victor Martin-Lozano🇩🇪 · Irene Valenzuela🇩🇪

    It is known that there are AdS vacua obtained from compactifying the SM to 2 or 3 dimensions. The existence of such vacua depends on the value of neutrino masses through the Casimir effect. Using the Weak Gravity Conjecture, it has been recently argued by Ooguri and Vafa that such vacua are incompatible with the SM embedding into a consistent theory of quantum gravity. We study the limits obtained for both the cosmological constant ${\Lambda }_4$ and neutrino masses from the absence of such dangerous 3D and 2D SM AdS vacua. One interesting implication is that ${\Lambda }_4$ is bounded to be larger than a scale of order $m_{\nu }^4$, as observed experimentally. Interestingly, this is the first argument implying a non-vanishing ${\Lambda }_4$ only on the basis of particle physics, with no cosmological input. Conversely, the observed ${\Lambda }_4$ implies strong constraints on neutrino masses in the SM and also for some BSM extensions including extra Weyl or Dirac spinors, gravitinos and axions. The upper bounds obtained for neutrino masses imply (for fixed neutrino Yukawa and ${\Lambda }_4$) the existence of upper bounds on the EW scale. In the case of massive Majorana neutrinos with a see-saw mechanism associated to a large scale $M\simeq 10^{10-14}$ GeV and $Y_{{\nu }_1}\simeq 10^{-3}$, one obtains that the EW scale cannot exceed $M_{EW}\lesssim 10^2-10^4$ GeV. From this point of view, the delicate fine-tuning required to get a small EW scale would be a mirage, since parameters yielding higher EW scales would be in the swampland and would not count as possible consistent theories. This would bring a new perspective into the issue of the EW hierarchy.

    ↳ hep-thhep-phJHEP(2017)·97 citations
25. 25*

    Solar neutrino physics on the beginning of 2017

    Francesco Vissani🇮🇹

    This writeup is a review of current hot topics on solar neutrinos. It is based on a talk at the conference "Neutrinos: the quest for a new physics scale", held at the CERN on March 2017, where the Organizers entrusted me with a discussion of the provocative question "whether solar neutrino physics is over". Rather than providing a straight (negative) answer, in view of an audience consisting mostly of colleagues working in theoretical particle physics, I deemed it more useful providing a description of what is the current activity of the physicists working in solar neutrinos, leaving the listener free of forming his/her own opinion apropos.

    ↳ nucl-thhep-phNucl.Phys.Atom.Energy(2017)·18 citations
26. 26*

    Foreground effect on the $J$-factor estimation of ultra-faint dwarf spheroidal galaxies

    Koji Ichikawa🇯🇵 · Shun-ichi Horigome🇯🇵 · Miho N. Ishigaki🇯🇵 · Shigeki Matsumoto🇯🇵 · Masahiro Ibe🇯🇵 · Hajime Sugai🇯🇵 · Kohei Hayashi🇯🇵

    Dwarf spheroidal galaxies (dSphs) are promising targets for the gamma-ray dark matter (DM) search. In particular, DM annihilation signal is expected to be strong in some of the recently discovered nearby ultra-faint dSphs, which potentially give stringent constraints on the $\mathcal{O}(1)$ TeV WIMP DM. However, various non-negligible systematic uncertainties complicate the estimation of the astrophysical factors relevant for the DM search in these objects. Among them, the effects of foreground stars particularly attract attention because the contamination is unavoidable even for the future kinematical survey. In this article, we assess the effects of the foreground contamination on the astrophysical $J$-factor estimation by generating mock samples of stars in the four ultra-faint dSphs and using a model of future spectrographs. We investigate various data cuts to optimize the quality of the data and apply a likelihood analysis which takes member and foreground stellar distributions into account. We show that the foreground star contaminations in the signal region (the region of interest) and their statistical uncertainty can be estimated by interpolating the foreground star distribution in the control region where the foreground stars dominate the member stars. Such regions can be secured at future spectroscopic observations utilizing a multiple object spectrograph with a large field of view; e.g. the Prime Focus Spectrograph mounted on Subaru Telescope. The above estimation has several advantages: The data-driven estimation of the contamination makes the analysis of the astrophysical factor stable against the complicated foreground distribution. Besides, foreground contamination effect is considered in the likelihood analysis.

    ↳ astro-ph.GAastro-ph.HEhep-phMNRAS(2018)·14 citations
27. 27*

    An alternative attractor in gauged NJL inflation

    Tomohiro Inagaki🇯🇵 · Sergei D. Odintsov🇪🇸 · Hiroki Sakamoto🇯🇵

    We have investigated the attractor structure for the CMB fluctuations in composite inflation scenario within the gauged Nambu-Jona-Lasinio (NJL) model. Such composite inflation represents an attractor which can not be found in a fundamental scalar model. As is known, the number of inflationary models contains the attractor classified by the $\alpha$-attractor model. It is found that the attractor inflation in the gauged NJL model corresponds to the $\alpha =2$ case.

    ↳ hep-thastro-ph.COgr-qchep-phEPL(2017)·2 citations
28. 28*

    Anomalous transport phenomena from dissipative charge pumping

    Tomoya Hayata🇯🇵

    The Berry curvature involving time and momentum derivatives, which we term emergent electric field, induces a nondisspative current known as the adiabatic charge pumping or Thouless pumping in periodically driven systems. We study dissipative currents originated from the interplay between emergent electric fields and electric/magnetic fields in two and three dimensions on the basis of the Boltzmann transport theory. As an example of two-dimensional models, we study the Rashba Hamiltonian with time-dependent and anisotropic spin-orbit coupling. We show that the interplay between emergent electric fields and electric fields leads to a current transverse to electric fields, which is symmetric and contributes to the entropy production. As an example of three-dimensional models, we study the Weyl Hamiltonian under AC electric fields. We show that the interplay between emergent electric fields and magnetic fields leads to a Hall-type current at zero DC electric fields, which is now transverse to DC magnetic fields: $j_x={\sigma }_{xy}{B}_y$ (${\sigma }_{xy}=-{\sigma }_{yx}$). The Hall photocurrent is relevant in the inversion symmetry breaking Weyl semimetals such as TaAs or SrSi${}_2$.

    ↳ cond-mat.mes-hallhep-phhep-th0 citations
29. 29*

    Proton structure fluctuations: from HERA to the LHC

    Heikki Mäntysaari🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Prithwish Tribedy🇺🇸

    We constrain the amount of event-by-event fluctuations of the proton by comparing with the HERA coherent and incoherent diffractive $J/\Psi$ production data. We find that the HERA measurements prefer large geometric fluctuations. We then include the constrained fluctuating proton shapes in viscous hydrodynamical simulations of the proton-nucleus collisions at $\sqrt{s_{NN}}=5.02$ TeV, and find a good description of the mean transverse momentum and flow harmonics measured at the LHC.

    ↳ nucl-thhep-phPoS(2018)·2 citations
30. 30*

    A universal order parameter for Inverse Magnetic Catalysis

    Alfonso Ballon-Bayona🇧🇷 · Matthias Ihl🇵🇹 · Jonathan P. Shock🇿🇦 · Dimitrios Zoakos🇵🇹

    We revisit the chiral transition in the finite density Sakai-Sugimoto model and find that, at fixed temperature $T$, the magnetisation near the critical line ${\mu }_c(B)$ acts as an order parameter to distinguish Inverse Magnetic Catalysis from Magnetic Catalysis. Moreover, we propose a universal relation between ${\mu }_c(B)$ and the magnetisation that allows us to predict the behaviour of the former from the behaviour of the latter. We find that a similar relation holds, at fixed chemical potential $\mu$, for the critical line $T_c(B)$. Our results are obtained by investigating a fully numerical solution to the relevant equations. At low temperatures our results reduce to those obtained by Preis, Rebhan and Schmitt [JHEP 1103 (2011) 033], based on a semi-analytic approximation.

    ↳ hep-thhep-phJHEP(2017)·32 citations
31. 31*

    Anomaly constraints on deconfinement and chiral phase transition

    Hiroyuki Shimizu🇯🇵 · Kazuya Yonekura🇯🇵

    We study constraints on thermal phase transitions of $\mathrm{SU}(N_c)$ gauge theories by using the 't Hooft anomaly involving the center symmetry and chiral symmetry. We consider two cases of massless fermions: (i) adjoint fermions, and (ii) $N_f$ flavors of fundamental fermions with a nontrivial greatest common divisor $\gcd (N_c,N_f)\ne 1$. For the first case (i), we show that the chiral symmetry restoration in terms of the standard Landau-Ginzburg effective action is impossible at a temperature lower than that of deconfinement. For the second case (ii), we introduce a modified version of the center symmetry which we call center-flavor symmetry, and draw similar conclusions under a certain definition of confinement. Moreover, at zero temperature, our results give a partial explanation of the appearance of dual magnetic gauge group in (supersymmetric) QCD when $\gcd (N_c,N_f)\ne 1$.

    ↳ hep-thhep-lathep-phPRD(2018)·123 citations
32. 32*

    Probing the small-scale structure in strongly lensed systems via transdimensional inference

    Tansu Daylan🇺🇸 · Francis-Yan Cyr-Racine🇺🇸 · Ana Diaz Rivero🇺🇸 · Cora Dvorkin🇺🇸 · Douglas P. Finkbeiner🇺🇸

    Strong lensing is a sensitive probe of the small-scale density fluctuations in the Universe. We implement a novel approach to modeling strongly lensed systems using probabilistic cataloging, which is a transdimensional, hierarchical, and Bayesian framework to sample from a metamodel (union of models with different dimensionality) consistent with observed photon count maps. Probabilistic cataloging allows us to robustly characterize modeling covariances within and across lens models with different numbers of subhalos. Unlike traditional cataloging of subhalos, it does not require model subhalos to improve the goodness of fit above the detection threshold. Instead, it allows the exploitation of all information contained in the photon count maps, for instance, when constraining the subhalo mass function. We further show that, by not including these small subhalos in the lens model, fixed-dimensional inference methods can significantly mismodel the data. Using a simulated Hubble Space Telescope (HST) dataset, we show that the subhalo mass function can be probed even when many subhalos in the sample catalogs are individually below the detection threshold and would be absent in a traditional catalog. With the planned Wide Field Infrared Space Telescope (WFIRST), simultaneous probabilistic cataloging of dark subhalos in high-resolution, deep strong lens images has the potential to constrain the subhalo mass function at even lower masses.

    ↳ astro-ph.COastro-ph.IMhep-phApJ(2018)·54 citations
33. 33*

    Onset of $\eta$-meson binding in the He isotopes

    N. Barnea🇮🇱 · E. Friedman🇺🇸 · A. Gal🇮🇱

    The onset of binding $\eta$(548) mesons in nuclei is studied in the He isotopes by doing precise $\eta NNN$ and $\eta NNNN$ few-body stochastic variational method calculations for two semi-realistic $NN$ potentials and two energy dependent $\eta N$ potentials derived from coupled-channel models of the $N^{\ast }(1535)$ nucleon resonance. The energy dependence of the $\eta N$ subthreshold input is treated self consistently. It is found that a minimal value of the real part of the $\eta N$ scattering length $a_{\eta N}$ close to 1 fm is required to bind $\eta$ mesons in ${}^3$He, yielding then a few MeV $\eta$ binding in ${}^4$He. The onset of $\eta$-meson binding in ${}^4$He requires that Re$a_{\eta N}$ exceeds 0.7 fm approximately. These results compare well with results of recent $\eta NNN$ and $\eta NNNN$ pionless effective field theory calculations. Related optical-model calculations are also discussed.

    ↳ nucl-thhep-phnucl-exNPA(2017)·34 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.