Tue·Oct 31, 2017Tuesday·October 31, 2017

1. 01*

   Another look at the impact of an eV-mass sterile neutrino on the effective neutrino mass of neutrinoless double-beta decays

   Jun-Hao Liu🇨🇳 · Shun Zhou🇨🇳

   The possible existence of an eV-mass sterile neutrino, slightly mixing with ordinary active neutrinos, is not yet excluded by neutrino oscillation experiments. Assuming neutrinos to be Majorana particles, we explore the impact of such a sterile neutrino on the effective neutrino mass of neutrinoless double-beta decays $⟨m{⟩}_{ee}^{\prime }\equiv m_1^{}|V_{e1}^{}{|}^2{e}^{\mathrm{i}\rho }+m_2^{}|V_{e2}^{}{|}^2+m_3^{}|V_{e3}^{}{|}^2{e}^{\mathrm{i}\sigma }+m_4^{}|V_{e4}^{}{|}^2{e}^{\mathrm{i}\omega }$, where $m_i^{}$ and $V_{ei}^{}$ (for $i=1,2,3,4$) denote respectively the absolute masses and the first-row elements of the 4$\times$4 neutrino flavor mixing matrix $V$, for which a full parametrization involves three Majorana-type CP-violating phases $\{\rho ,\sigma ,\omega \}$. A zero effective neutrino mass $|⟨m{⟩}_{ee}^{\prime }|=0$ is possible no matter whether three active neutrinos take the normal or inverted mass ordering, and its implications for the parameter space are examined in great detail. In particular, given the best-fit values of $m_4^{}\approx 1.3\mathrm{eV}$ and $|V_{e4}^{}{|}^2\approx 0.019$ from the latest global analysis of neutrino oscillation data, a three-dimensional view of $|⟨m{⟩}_{ee}^{\prime }|$ in the $(m_1^{},\rho )$-plane is presented and further compared with that of the counterpart $|⟨m{⟩}_{ee}^{}|$ in the absence of any sterile neutrino.

   hep-phInt.J.Mod.Phys.A(2018)·15 citations
2. 02*

   Renormalization Group Invariance of the Pole Mass in the Multi-Higgs system

   Chungku Kim🇺🇸

   We have investigated the renormalization group running of the pole mass in the multi-Higgs theory in two different types of the gauge fixing conditions. It turns out that the pole mass when expressed in terms of the Lagrangian parameters, is invariant under the renormalization group with the beta and gamma functions of the symmetric phase.

   hep-phJ.Korean Phys.Soc.(2018)·1 citation
3. 03*

   High scale impact in alignment and decoupling in two-Higgs doublet models

   Philipp Basler🇩🇪 · Pedro M. Ferreira🇵🇹 · Margarete Mühlleitner🇩🇪 · Rui Santos🇵🇹

   The two-Higgs doublet model (2HDM) provides an excellent benchmark to study physics beyond the Standard Model (SM). In this work we discuss how the behaviour of the model at high energy scales causes it to have a scalar with properties very similar to those of the SM -- which means the 2HDM can be seen to naturally favor a decoupling or alignment limit. For a type II 2HDM, we show that requiring the model to be theoretically valid up to a scale of 1 TeV, by studying the renormalization group equations (RGE) of the parameters of the model, causes a significant reduction in the allowed magnitude of the quartic couplings. This, combined with $B$-physics bounds, forces the model to be naturally decoupled. As a consequence, any non-decoupling limits in type II, like the wrong-sign scenario, are excluded. On the contrary, even with the very constraining limits for the Higgs couplings from the LHC, the type I model can deviate substantially from alignment. An RGE analysis similar to that made for type II shows, however, that requiring a single scalar to be heavier than about 500 GeV would be sufficient for the model to be decoupled. Finally, we show that not only a 2HDM where the lightest of the CP-even scalars is the 125 GeV one does not require new physics to be stable up to the Planck scale but this is also true when the heavy CP-even Higgs is the 125 GeV and the theory has no decoupling limit for the type I model.

   hep-phPRD(2018)·42 citations
4. 04*

   Involution symmetries and the PMNS matrix

   Palash B. Pal🇮🇳 · Pritibhajan Byakti🇮🇳

   Lam suggested that the PMNS matrix (or at least some of its elements) can be predicted by embedding the residual symmetry of the leptonic mass terms into a bigger symmetry. We analyze the possibility that the residual symmetries consist of involution generators only and explore how Lam's idea can be implemented.

   hep-phPramana(2017)·0 citations
5. 05*

   The Minimal Axion Minimal Linear $\sigma$ Model

   L. Merlo🇪🇸 · F. Pobbe🇮🇹 · S. Rigolin🇮🇹

   The minimal $SO(5)/SO(4)$ linear $\sigma$ model is extended including an additional complex scalar field, singlet under the global $SO(5)$ and the Standard Model gauge symmetries. The presence of this scalar field creates the conditions to generate an axion à la KSVZ, providing a solution to the strong CP problem, or an axion-like-particle. Different choices for the PQ charges are possible and lead to physically distinct Lagrangians. The internal consistency of each model necessarily requires the study of the scalar potential describing the $SO(5)\to SO(4)$, electroweak and PQ symmetry breaking. A single minimal scenario is identified and the associated scalar potential is minimised including counterterms needed to ensure one-loop renormalizability. In the allowed parameter space, phenomenological features of the scalar degrees of freedom, of the exotic fermions and of the axion are illustrated. Two distinct possibilities for the axion arise: either it is a QCD axion with an associated scale larger than $\sim 10^5$ TeV and therefore falling in the category of the invisible axions; or it is a more massive axion-like-particle, such as a $1$ GeV axion with an associated scale of $\sim 200$ TeV, that may show up in collider searches.

   hep-phEPJC(2018)·24 citations
6. 06*

   Combined parametrization of the neutron electric form factor and the ${\gamma }^{\ast }N\to \Delta (1232)$ quadrupole form factors

   G. Ramalho🇧🇷

   Models based on $SU(6)$ symmetry breaking and large $N_c$ limit provide relations between the pion cloud contributions to the ${\gamma }^{\ast }N\to \Delta (1232)$ quadrupole form factors, electric ($G_E$) and Coulomb ($G_C$), and the neutron electric form factor $G_{En}$, suggesting that those form factors are dominated by the same physical processes. Those relations are improved in order to satisfy a fundamental constraint between the electric and Coulomb quadrupole form factors in the long wavelength limit, when the photon three-momentum vanishes (Siegert's theorem). Inspired by those relations, we study alternative parametrizations for the neutron electric form factor. The parameters of the new form are then determined by a combined fit to the $G_{En}$ and the ${\gamma }^{\ast }N\to \Delta (1232)$ quadrupole form factor data. We obtain a very good description of the $G_E$ and $G_C$ data when we combine the pion cloud contributions with small valence quark contributions to the ${\gamma }^{\ast }N\to \Delta (1232)$ quadrupole form factors. The best description of the data is obtained when the second momentum of $G_{En}$ is $r_n^4\simeq -0.4$ fm${}^4$. We conclude that the square radii associated with $G_E$ and $G_C$, $r_E^2$ and $r_C^2$, respectively, are large, revealing the long extension of the pion cloud. We conclude also that those square radii are related by $r_E^2-r_C^2=0.6\pm 0.2$ fm${}^2$. The last result is mainly the consequence of the pion cloud effects and Siegert's theorem.

   hep-phhep-exhep-latnucl-ex+1EPJA(2019)·15 citations
7. 07*

   Shape of Proton and the Pion Cloud

   László Jenkovszky🇺🇦 · István Szanyi🇺🇦 · Chung-I Tan🇺🇸

   Proton-proton differential and total cross sections provide information on the energy dependence of proton shape and size. We show that the deviation from exponential behavior of the diffraction cone observed near $t=-0.1$ GeV${}^2$, (so-called break), both at the ISR and the LHC follows from the $t$-channel two-pion loop contributions, imposed by unitarity. By using a simple Regge-pole model, we extrapolate the "break" from the ISR energy region to that of the LHC. This allows us to answer two important questions: 1) To what extent is the "break" observed recently at the LHC a "recurrence" of that seen at the ISR (universality)? 2) What is the relative weight of two-pion effect to the vertex coupling (Regge residue) compared to expanding size (pomeron propagator) in producing the "break"? We find that the effect comes both from the Regge residue (proton-pomeron coupling) and from the Regge propagator. A detail analyses of their balance, including the correlation between the relevant parameters is presented.

   hep-phEPJA(2018)·27 citations
8. 08*

   Natural SUSY at LHC with Right-Sneutrino LSP

   Arindam Chatterjee🇮🇳 · Juhi Dutta🇮🇳 · Santosh Kumar Rai🇮🇳

   We study an extension of the minimal supersymmetric standard model (MSSM) with additional right-handed singlet neutrino superfields. While such an extension incorporates a mechanism for the neutrino mass, it also opens up the possibility of having the right-sneutrinos ($\tilde{\nu }$) as the lightest supersymmetric particle (LSP). In this work, we focus on the the viability of rather small ($\lesssim 500$ GeV) higgsino mass parameter ($\mu$), an important ingredient for "naturalness", in the presence of such a LSP. For simplicity, we assume that the bino and wino mass parameters are much heavier, thus we only consider (almost) pure and compressed higgsino-like states, with small $\mathcal{O}(10^{-2})$ gaugino admixture. Considering only prompt decays of the higgino-like states, especially the lightest chargino, we discuss the importance of leptonic channels consisting of up to two leptons with large missing transverse energy to probe this scenario at the Large Hadron Collider (LHC). Further, we emphasize on how the gaugino mass parameters, although very heavy, affects the decay of the low-lying higgsino-like states, thus significantly affecting the proposed signatures at LHC.

   hep-phJHEP(2018)·11 citations
9. 09*

   Eikonal model analysis of elastic proton-proton collisions at 52.8 GeV and 8 TeV

   Jiri Prochazka🇨🇿 · Vojtech Kundrat🇨🇿 · Milos V. Lokajicek🇨🇿

   Under the influence of standardly used description of Coulomb-hadronic interference proposed by West and Yennie the protons have been interpreted as transparent objects; elastic events have been interpreted as more central than inelastic ones. It is known that using more general eikonal model the measured elastic data may be interpreted also very differently; elastic processes being more peripheral than inelastic ones. The most ample elastic data set measured at ISR energy of 52.8 GeV have been recently reanalyzed with the help of the eikonal model and new results obtained. The impact of recently established electromagnetic form factors on determination of quantities specifying hadron interaction determined from the fits of experimental elastic data have been studied. The influence of some other assumptions on proton characteristics derived from elastic hadronic scattering amplitude determined on the basis of experimental data have been analyzed, too. It concerns mainly the assumed $t$-dependence of phase of elastic hadronic amplitude. The results may be then compared to similar analysis of experimental data at much higher LHC energy of 8 TeV recently published by TOTEM experiment.

   hep-ph3 citations
10. 10*

    Form Factors and Differential Branching Ratio of $B\to K{\mu }^{+}{\mu }^{-}$ in AdS/QCD

    S. Momeni🇮🇷 · R. Khosravi🇮🇷

    The light-front distribution amplitudes (LFDAs) and the decay constant of the $K$ pseudoscalar meson are extracted within the framework of the AdS/QCD correspondence. For the LFDAs calculation, we consider a momentum-dependent (dynamical) helicity wave function which contains the dynamical spin effects. We use the LFDAs to predict the transition form factors of the semileptonic $B\to K{\ell }^{+}{\ell }^{-}$ decay. With the help of these form factors, the differential branching ratio of the $B\to K{\mu }^{+}{\mu }^{-}$ on $q^2$ is plotted. A comparison is made between our prediction in AdS/QCD and the results obtained from two models including the light-cons sum rules (LCSR) and lattice QCD as well as the experimental values.

    hep-phPRD(2018)·6 citations
11. 11*

    Two Higgs Doublet Dark Matter Portal

    Nicole F. Bell🇦🇺 · Giorgio Busoni🇦🇺 · Isaac W. Sanderson🇦🇺

    We study a fermionic dark matter model in which the interaction of the dark and visible sectors is mediated by Higgs portal type couplings. Specifically, we consider the mixing of a dark sector scalar with the scalars of a Two Higgs Doublet Model extension of the Standard Model. Given that scalar exchange will result in a spin-independent dark matter-nucleon scattering cross section, such a model is potentially subject to stringent direct detection constraints. Moreover, the addition of new charged scalars introduce non-trivial flavour constraints. Nonetheless, this model allows more freedom than a standard Higgs portal scenario involving a single Higgs doublet, and much of the interesting parameter space is not well approximated by a Simplified Model with a single scalar mediator. We perform a detailed parameter scan to determine the mass and coupling parameters which satisfy direct detection, flavour, precision electroweak, stability, and perturbativity constraints, while still producing the correct relic density through thermal freezeout.

    hep-phJCAP(2018)·44 citations
12. 12*

    Testing Higgs boson scenarios in the phenomenological NMSSM

    Shehu AbdusSalam🇮🇷

    There could be another scalar in nature quasi-degenerate with the observed one (h125). This is possible in models such as the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The scenario(s) with a single Higgs boson can be compared to that with multiple ones, all near 125 GeV. In order to assess the extent to which the current set of collider, cold dark matter relic density and direct detection limits are capable of discriminating these scenarios, we perform, for the first-time, global fits of a weak-scale phenomenological NMSSM with 26 free parameters using the nested sampling implementation in PolyChord, a next-generation tool for Bayesian inference. The analyses indicate that the data used shows a moderate tendency for supporting the scenario with an additional scalar much lighter than h125 with mass distribution centred below the W-boson mass. More stringent constraints are, however, needed for decisive inference regarding an additional Higgs boson with mass much less than or near 125 GeV.

    hep-phhep-exEPJC(2019)·8 citations
13. 13*

    Possible open-charmed pentaquark molecule ${\Omega }_c(3188)$ --- the $D\Xi$ bound state --- in the Bethe-Salpeter formalism

    Chao Wang🇨🇳 · Liang-Liang Liu🇨🇳 · Xian-Wei Kang🇹🇼 · Xin-Heng Guo🇨🇳 · Rui-Wu Wang🇨🇳

    We study the $S$-wave $D\Xi$ bound state in the Bethe-Salpeter formalism in the ladder and instantaneous approximations. With the kernel generated by the hadronic effective Lagrangian, two open-charmed bound states, which quantum numbers are $I=0$, $J^P=(\frac{1}{2}{)}^{-}$ and $I=1$, $J^P=(\frac{1}{2}{)}^{-}$, respectively, are predicted as new candidates of hadronic pentaquark molecules in our formalism. If existing, they could contribute to the broad 3188 eV structure near the five new narrow ${\Omega }_c$ states observed recently by the LHCb Collaboration.

    hep-phEPJC(2018)·34 citations
14. 14*

    $\gamma \gamma \to \gamma \gamma$ scattering in ultrarelativistic UPC

    Antoni Szczurek🇵🇱 · Mariola Klusek-Gawenda🇵🇱

    We discuss diphoton semi(exclusive) production in ultraperipheral lead-lead collisions at energy of $\sqrt{s_{NN}}$ = 5.5 TeV (LHC) and in proton-proton collisions at $\sqrt{s_{pp}}$ = 7 TeV (LHC) and $\sqrt{s_{pp}}$ = 100 TeV (FCC). The nuclear calculations are based on equivalent photon approximation in the impact parameter space. The cross sections for elementary $\gamma \gamma \to \gamma \gamma$ subprocess are calculated including three different mechanisms: box diagrams with leptons and quarks in the loops, a VDM-Regge contribution with virtual intermediate hadronic excitations of the photons and the two-gluon exchange contribution. We get relatively high cross sections in heavy ion collisions. This opens a possibility to study the light-by-light (quasi)elastic scattering at the LHC. We find that the cross section for elastic $\gamma \gamma$ scattering could be measured in the lead-lead collisions for the diphoton invariant mass up to $W_{\gamma \gamma }\approx$ 15 - 20 GeV. Our Standard Model predictions are compared to a recent ATLAS experimental result. We present differential distributions for PbPb$\to$PbPb$\gamma \gamma$ and pp$\to$pp$\gamma \gamma$ reaction.

    hep-phnucl-thPoS(2017)·1 citation
15. 15*

    Kroll-Lee-Zumino quantum field theory of pionic interactions: rho-meson propagator at two-loop level and electromagnetic pion form factor

    C. A. Dominguez🇿🇦 · M. Lushozi🇿🇦 · K. Schilcher🇿🇦

    The Kroll-Lee-Zumino renormalizable Abelian quantum field theory of pionic strong interactions is used to compute the rho-meson propagator at the two-loop level.

    hep-ph0 citations
16. 16*

    Constraining Photon Portal Dark Matter with Texono and Coherent Data

    Shao-Feng Ge🇯🇵 · Ian M. Shoemaker🇺🇸

    Dark matter may reside in sector without Standard Model (SM) gauge interactions. One way in which such a dark sector can still impact SM particles through non-gravitational interactions is via the "photon portal" in which a dark photon kinetically mixes with the ordinary SM photon. We study the implications of this setup for electron recoil events at TEXONO reactor and nuclear recoil events at the COHERENT experiment. We find that the recent COHERENT data rules out previously allowed regions of parameter space favored by the thermal relic hypothesis for the DM abundance. When mapped onto the DM-electron cross section, we find that COHERENT provides the leading direct constraints for DM masses < 30 MeV.

    hep-phhep-exJHEP(2018)·94 citations
17. 17*

    Baryon production from cluster hadronization

    Stefan Gieseke🇩🇪 · Patrick Kirchgaeßer🇩🇪 · Simon Plätzer🇦🇹

    We present an extension to the colour reconnection model in the Monte-Carlo event generator Herwig to account for the production of baryons and compare it to a series of observables for soft physics. The new model is able to improve the description of charged-particle mutliplicities and hadron flavour observables in pp collisions

    hep-phEPJC(2018)·72 citations
18. 18*

    Soft and diffractive scattering

    Stefan Gieseke🇩🇪 · Patrick Kirchgaeßer🇩🇪 · Frasher Loshaj🇩🇪

    A model for soft and diffractive scattering is presented which is incorporated seamlessly into the pre-existing MPI model in the Monte Carlo Event Generator Herwig. With the improved model we are able to describe general aspects of Minimum Bias and Underlying Event data.

    hep-ph2 citations
19. 19*

    One-loop amplitudes with an off-shell gluon

    A. van Hameren🇵🇱

    I report on recent advancements regarding calculations that require initial-state partons with non-vanishing transverse momentum, causing it to be space-like and thus off-shell.

    hep-ph0 citations
20. 20*

    From Jacobi off-shell currents to integral relations

    Jose Llanes Jurado🇪🇸 · German Rodrigo🇪🇸 · William J. Torres Bobadilla🇪🇸

    In this paper, we study off-shell currents built from the Jacobi identity of the kinematic numerators of $gg\to X$ with $X=ss,q\bar{q},gg$. We find that these currents can be schematically written in terms of three-point interaction Feynman rules. This representation allows for a straightforward understanding of the Colour-Kinematics duality as well as for the construction of the building blocks for the generation of higher-multiplicity tree-level and multi-loop numerators. We also provide one-loop integral relations through the Loop-Tree duality formalism with potential applications and advantages for the computation of relevant physical processes at the Large Hadron Collider. We illustrate these integral relations with the explicit examples of QCD one-loop numerators of $gg\to ss$.

    hep-phhep-thJHEP(2017)·40 citations
21. 21*

    Instantaneous Bethe-Salpeter Look at the Lightest Pseudoscalar Mesons

    Wolfgang Lucha🇦🇹 · Franz F. Schoberl🇦🇹

    Within our description of Goldstone-type pseudoscalar mesons as almost massless bound states of quark and antiquark by a three-dimensional bound-state equation of Bethe-Salpeter origin, taking into account the pointwise behaviour of the full light-quark propagators enables to characterize the effective interquark interactions more precisely than earlier studies exploiting just specific aspects.

    hep-phnucl-thPoS(2018)·0 citations
22. 22*

    On the tuning in the $(m_h,m_t)$ plane: Standard Model criticality vs. High-scale SUSY

    Gino Isidori🇨🇭 · Andrea Pattori🇮🇹

    We analyse the predictions of both Higgs and top masses in a generic MSSM satisfying gauge-coupling unification, radiative electroweak symmetry breaking, with a natural (non-splitted) spectrum of soft-breaking terms, and an arbitrary soft-breaking scale (above a few TeV). This procedure allows us to identify a relatively narrow SUSY-allowed region in the $(m_h,m_t)$ plane. We argue that the compatibility of the measured values of Higgs and top masses with this SUSY-allowed region is not less surprising than the corresponding compatibility with the narrow SM metastability region. As such, it provides a non-trivial signal of the compatibility of present data with a supersymmetric completion of the SM.

    hep-phPLB(2018)·2 citations
23. 23*

    Thermodynamic potential for quark-gluon plasma with finite quark masses and chemical potential

    Mayukh R. Gangopadhyay🇮🇳 · Grant J. Mathews🇺🇸 · J. Pocahontas Olson🇺🇸

    We summarize the derivation of the finite temperature, finite chemical potential thermodynamic potential in the bag-model approximation to quantum chromodynamics (QCD) that includes a finite $s$-quark mass in the Feynman diagram contributions for both zero-order and two-loop corrections to the quark interaction. The thermodynamic potential for quarks in QCD is a desired ingredient for computations of the equation of state in the early universe, supernovae, neutron stars, and heavy-ion collisions. The 2-loop contributions are normally divergent and become even more difficult in the limit of finite quark masses and finite chemical potential. We introduce various means to interpolate between the low and high chemical potential limits. Although physically well motivated, we show that the infinite series Padé rational polynomial interpolation scheme introduces spurious poles. Nevertheless, we show that lower order interpolation schemes such as polynomial interpolation reproduce the Padé result without the presence of spurious poles. We propose that in this way one can determine the equation of state for the two-loop corrections for arbitrary chemical potential, temperature and quark mass. This provides a new realistic bag-model treatment of the QCD equation of state. We compute the QCD phase diagram with up to the two-loop corrections. We show that the two-loop corrections decrease the pressure of the quark-gluon plasma and therefore increase the critical temperature and chemical potential of the phase transition. We also show, however, that the correction for finite $s$-quark mass in the two-loop correction serves to decrease the critical temperature for the quark-hadron phase transition in the early universe.

    hep-phastro-ph.COJ.Phys.Comm.(2020)·1 citation
24. 24*

    Likelihood Analysis of the pMSSM11 in Light of LHC 13-TeV Data

    E. Bagnaschi🇩🇪 · K. Sakurai🇵🇱 · M. Borsato🇪🇸 · O. Buchmueller🇬🇧 · M. Citron🇬🇧 · J. C. Costa🇬🇧 · A. De Roeck🇨🇭 · M.J. Dolan🇦🇺 · J.R. Ellis🇬🇧 · H. Flächer🇬🇧 · S. Heinemeyer🇪🇸 · M. Lucio🇪🇸 and 6 other authors

    We use MasterCode to perform a frequentist analysis of the constraints on a phenomenological MSSM model with 11 parameters, the pMSSM11, including constraints from ~ 36/fb of LHC data at 13 TeV and PICO, XENON1T and PandaX-II searches for dark matter scattering, as well as previous accelerator and astrophysical measurements, presenting fits both with and without the $(g-2{)}_{\mu }$ constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses $M_{1,2,3}$, a common mass for the first-and second-generation squarks $m_{\tilde{q}}$ and a distinct third-generation squark mass $m_{{\tilde{q}}_3}$, a common mass for the first-and second-generation sleptons $m_{\tilde{l}}$ and a distinct third-generation slepton mass $m_{\tilde{\tau }}$, a common trilinear mixing parameter $A$, the Higgs mixing parameter $\mu$, the pseudoscalar Higgs mass $M_A$ and $\tan \beta$. In the fit including $(g-2{)}_{\mu }$, a Bino-like ${\tilde{\chi }}_1^0$ is preferred, whereas a Higgsino-like ${\tilde{\chi }}_1^0$ is favoured when the $(g-2{)}_{\mu }$ constraint is dropped. We identify the mechanisms that operate in different regions of the pMSSM11 parameter space to bring the relic density of the lightest neutralino, ${\tilde{\chi }}_1^0$, into the range indicated by cosmological data. In the fit including $(g-2{)}_{\mu }$, coannihilations with ${\tilde{\chi }}_2^0$ and the Wino-like ${\tilde{\chi }}_1^{\pm }$ or with nearly-degenerate first- and second-generation sleptons are favoured, whereas coannihilations with the ${\tilde{\chi }}_2^0$ and the Higgsino-like ${\tilde{\chi }}_1^{\pm }$ or with first- and second-generation squarks may be important when the $(g-2{)}_{\mu }$ constraint is dropped. Prospects remain for discovering strongly-interacting sparticles at the LHC as well as for discovering electroweakly-interacting sparticles at a future linear $e^{+}{e}^{-}$ collider such as the ILC or CLIC.

    hep-phastro-ph.HEhep-exEPJC(2018)·156 citations
25. 25*

    Connecting $b\to s\ell \bar{\ell }$ anomalies to enhanced rare nonleptonic ${\bar{B}}_s^0$ decays in $Z^{\prime }$ model

    Gaber Faisel🇹🇷 · Jusak Tandean🇹🇼

    The present data on a number of observables in $b\to s{\mu }^{+}{\mu }^{-}$ processes manifest some tensions with the standard model (SM). Assuming that these anomalies have a new physics origin, we consider the possibility that a $Z^{\prime }$ boson is responsible for them. We further assume that its interactions with quarks also affect rare nonleptonic decays of the ${\bar{B}}_s^0$ meson which are purely isospin-violating and tend to be dominated by electroweak-penguin contributions, namely ${\bar{B}}_s^0\to (\eta ,{\eta }^{\prime },\varphi )({\pi }^0,{\rho }^0)$. Most of these decays are not yet observed, and their rates are expected to be relatively small in the SM. Taking into account constraints from various measurements, including the evidence for ${\bar{B}}_s^0\to \varphi {\rho }^0$ recently seen by LHCb, we find that the $Z^{\prime }$ effects on ${\bar{B}}_s^0\to (\eta ,\varphi ){\pi }^0$ can make their rates bigger than the SM predictions by up to an order of magnitude. For ${\bar{B}}_s^0\to {\eta }^{\prime }{\pi }^0,(\eta ,{\eta }^{\prime }){\rho }^0$, the enhancement factors are at most a few. Since the $Z^{\prime }$ contributions to the different channels depend on different combinations of its couplings, observations of more of these decays in future experiments, along with improved $b\to s{\mu }^{+}{\mu }^{-}$ data, will probe this $Z^{\prime }$ scenario more thoroughly.

    hep-phhep-exJHEP(2018)·35 citations
26. 26*

    The ALP miracle revisited

    Ryuji Daido🇯🇵 · Fuminobu Takahashi🇯🇵 · Wen Yin🇨🇳

    We revisit the ALP miracle scenario where the inflaton and dark matter are unified by a single axion-like particle (ALP). We first extend our previous analysis on the inflaton dynamics to identify the whole viable parameter space consistent with the CMB observation. Then, we evaluate the relic density of the ALP dark matter by incorporating uncertainties of the model-dependent couplings to the weak gauge bosons as well as the dissipation effect. The preferred ranges of the ALP mass and coupling to photons are found to be $0.01\lesssim m_{\varphi }\lesssim 1$\,eV and $g_{\varphi \gamma \gamma }=\mathcal{O}(10^{-11})$\,GeV${}^{-1}$, which slightly depend on these uncertainties. Interestingly, the preferred regions are within reach of future solar axion helioscope experiments, IAXO and TASTE, and laser-based stim

    hep-phastro-ph.COastro-ph.GAgr-qc+1JHEP(2018)·108 citations
27. 27*

    A Preview of Global Fits of Axion Models in GAMBIT

    Sebastian Hoof (for the GAMBIT Collaboration)🇬🇧

    There are currently many experimental searches underway that try to detect QCD axions and axion-like particles. These, in addition to other constraints from astrophysics and cosmology, require a consistent and statistically rigorous analysis of the large landscape of axion models. Here, we present the rationale, methodology and preliminary results for global fits of axion models using the recently developed software framework GAMBIT.

    hep-ph2 citations
28. 28*

    Revealing timid pseudo-scalars with taus at the LHC

    Giacomo Cacciapaglia (Lyon, IPN)🇫🇷 · Gabriele Ferretti (Chalmers U. Tech.)🇸🇪 · Thomas Flacke (IBS, Daejeon)🇰🇷 · Hugo Serodio (Lund U.)🇸🇪

    A light pseudo-scalar that is copiously produced at the LHC may still be allowed by present searches. While masses above 65 GeV are effectively covered by di-photon searches, the lower mass window can be tested by a new search for boosted di-tau resonances. We test this strategy on a set of composite Higgs models with top partial compositeness, where most models can be probed with an integrated luminosity below 300 fb${}^{-1}$.

    hep-phhep-exEPJC(2018)·40 citations
29. 29*

    Large-N kinetic theory for highly occupied systems

    R. Walz🇩🇪 · K. Boguslavski🇫🇮 · J. Berges🇩🇪

    We consider an effective kinetic description for quantum many-body systems, which is not based on a weak-coupling or diluteness expansion. Instead, it employs an expansion in the number of field components N of the underlying scalar quantum field theory. Extending previous studies, we demonstrate that the large-N kinetic theory at next-to-leading order is able to describe important aspects of highly occupied systems, which are beyond standard perturbative kinetic approaches. We analyze the underlying quasiparticle dynamics by computing the effective scattering matrix elements analytically and solve numerically the large-N kinetic equation for a highly occupied system far from equilibrium. This allows us to compute the universal scaling form of the distribution function at an infrared nonthermal fixed point within a kinetic description and we compare to existing lattice field theory simulation results.

    hep-phcond-mat.quant-gasPRD(2018)·60 citations
30. 30*

    A Search for Dark Matter in the Galactic Halo with HAWC

    A. U. Abeysekara🇺🇸 · A. M. Albert🇺🇸 · R. Alfaro🇲🇽 · C. Alvarez · J. D. Álvarez · R. Arceo🇲🇽 · J. C. Arteaga-Velázquez🇲🇽 · D. Avila Rojas🇲🇽 · H. A. Ayala Solares🇺🇸 · A. Becerril🇲🇽 · E. Belmont-Moreno🇲🇽 · S. Y. BenZvi🇺🇸 and 91 other authors

    The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 500 GeV - 100 TeV gamma rays and cosmic rays. With its observations over 2/3 of the sky every day, the HAWC observatory is sensitive to a wide variety of astrophysical sources, including possible gamma rays from dark matter. Dark matter annihilation and decay in the Milky Way Galaxy should produce gamma-ray signals across many degrees on the sky. The HAWC instantaneous field-of-view of 2 sr enables observations of extended regions on the sky, such as those from dark matter in the Galactic halo. Here we show limits on the dark matter annihilation cross-section and decay lifetime from HAWC observations of the Galactic halo with 15 months of data. These are some of the most robust limits on TeV and PeV dark matter, largely insensitive to the dark matter morphology. These limits begin to constrain models in which PeV IceCube neutrinos are explained by dark matter which primarily decays into hadrons.

    ↳ astro-ph.HEastro-ph.COhep-phJCAP(2018)·108 citations
31. 31*

    The pion vector form factor from Lattice QCD at the physical point

    C. Alexandrou🇨🇾 · S. Bacchio🇨🇾 · P. Dimopoulos🇮🇹 · J. Finkenrath🇨🇾 · R. Frezzotti🇮🇹 · K. Jansen🇩🇪 · B. Kostrzewa🇩🇪 · M. Mangin-Brinet🇫🇷 · F. Sanfilippo🇮🇹 · S. Simula🇮🇹 · C. Urbach🇩🇪 · U. Wenger🇨🇭

    We present an investigation of the electromagnetic pion form factor, $F_{\pi }(Q^2)$, at small values of the four-momentum transfer $Q^2$ ($\lesssim 0.25$ GeV${}^2$), based on the gauge configurations generated by European Twisted Mass Collaboration with $N_f=2$ twisted-mass quarks at maximal twist including a clover term. Momentum is injected using non-periodic boundary conditions and the calculations are carried out at a fixed lattice spacing ($a\simeq 0.09$ fm) and with pion masses equal to its physical value, 240 MeV and 340 MeV. Our data are successfully analyzed using Chiral Perturbation Theory at next-to-leading order in the light-quark mass. For each pion mass two different lattice volumes are used to take care of finite size effects. Our final result for the squared charge radius is $⟨r^2{⟩}_{\pi }=0.443(29)$ fm${}^2$, where the error includes several sources of systematic errors except the uncertainty related to discretization effects. The corresponding value of the SU(2) chiral low-energy constant ${\overline{\ell }}_6$ is equal to ${\overline{\ell }}_6=16.2(1.0)$.

    ↳ hep-lathep-phPRD(2018)·37 citations
32. 32*

    General purpose graphics-processing-unit implementation of cosmological domain wall network evolution

    J. R. C. C. C. Correia🇵🇹 · C. J. A. P. Martins🇵🇹

    Topological defects unavoidably form at symmetry breaking phase transitions in the early Universe. To probe the parameter space of theoretical models and set tighter experimental constraints (exploiting the recent advances in astrophysical observations), one requires more and more demanding simulations, and therefore more hardware resources and computation time. Improving the speed and efficiency of existing codes is essential. Here we present a General Purpose Graphics Processing Unit implementation of the canonical Press-Ryden-Spergel algorithm for the evolution of cosmological domain wall networks. This is ported to the Open Computing Language standard, and as a consequence significant speed-ups are achieved both in 2D and 3D simulations.

    ↳ physics.comp-phastro-ph.COhep-phPRE(2017)·12 citations
33. 33*

    Heavy Nuclei as Thermal Insulation for Proto-Neutron Stars

    Ken'ichiro Nakazato🇯🇵 · Hideyuki Suzuki🇯🇵 · Hajime Togashi🇯🇵

    A proto-neutron star (PNS) is a newly formed compact object in a core collapse supernova. In this Letter, the neutrino emission from the cooling process of a PNS is investigated using two types of nuclear equation of state (EOS). It is found that the neutrino signal is mainly determined by the high-density EOS. The neutrino luminosity and mean energy are higher and the cooling time scale is longer for the softer EOS. Meanwhile, the neutrino mean energy and the cooling time scale are also affected by the low-density EOS because of the difference in the population of heavy nuclei. Heavy nuclei have a large scattering cross section with neutrinos owing to the coherent effects and act as thermal insulation near the surface of a PNS. The neutrino mean energy is higher and the cooling time scale is longer for an EOS with a large symmetry energy at low densities, namely a small density derivative coefficient of the symmetry energy, $L$.

    ↳ astro-ph.HEhep-phnucl-thPRC(2018)·34 citations
34. 34*

    Primordial Perturbation of Dark Matter as a Novel Probe of Very Early Universe

    Changhong Li🇨🇳

    Dark matter(DM) is the only possible candidate which would be apart from the thermal equilibrium before Big Bang nucleosynthesis(BBN) in accordance with current DM searches. In this work, we report a generic scenario that primordial perturbation of dark matter(PPDM) can be, effectively, generated and encoded with primordial information of very early universe up to the reheating era. We present an analytical solution of the whole evolution of PPDM. A novel and strong constraint on the reheating process imposed by primordial gravitational wave(PGW) is obtained for the first time. It indicates the ratio of PGW to primordial curvature perturbation(PCP) is not only dependent on the slow-roll spectral index but also, strongly, on the decay process of inflaton at reheating. For very generic reheating process, our result provides a natural explanation of the paucity of PGW in current observations.

    ↳ astro-ph.COhep-ph0 citations
35. 35*

    Modification of the masses of the lightest neutral mesons in a hadronic medium under an external magnetic field

    R. M. Aguirre🇦🇷

    The effective masses of the neutral mesons in a hadronic medium and under an external magnetic field are evaluated as functions of the baryonic density and the field intensity. For this purpose the meson polarization is evaluated in the one loop approximation using a Quantum Hadrodynamics model which includes pions, sigma, omega, and rho mesons. The propagators of the baryons include the full effect of the coupling to the magnetic field through their charges and their anomalous magnetic moments. Within the range of magnetic intensities considered here $10^{17}$ G $<B<10^{19}$ G, the dependence on B is moderate for the pion and the longitudinal component of the omega meson, and negligible for the remaining mesons.

    ↳ nucl-thhep-phPRD(2017)·20 citations
36. 36*

    Life Outside the Golden Window: Statistical Angles on the Signal-to-Noise Problem

    Michael L. Wagman🇺🇸

    Lattice QCD simulations of multi-baryon correlation functions can predict the structure and reactions of nuclei without encountering the baryon chemical potential sign problem. However, they suffer from a signal-to-noise problem where Monte Carlo estimates of observables have quantum fluctuations that are exponentially larger than their average values. Recent lattice QCD results demonstrate that the complex phase of baryon correlations functions relates the baryon signal-to-noise problem to a sign problem and exhibits unexpected statistical behavior resembling a heavy-tailed random walk on the unit circle. Estimators based on differences of correlation function phases evaluated at different Euclidean times are discussed that avoid the usual signal-to-noise problem, instead facing a signal-to-noise problem as the time interval associated with the phase difference is increased, and allow hadronic observables to be determined from arbitrarily large-time correlation functions.

    ↳ hep-latcond-mat.stat-mechhep-phEPJ Web Conf.(2018)·4 citations
37. 37*

    Terrestrial WIMP/Axion astronomy

    Ciaran A. J. O'Hare🇬🇧

    Predicting signals in direct dark matter (DM) detection experiments requires an understanding of the astrophysical structure of the local halo. Any uncertainty in this understanding will feed directly into all experimental results. However our terrestrial experiments are in a position to study this same astrophysical dependence, and in fact represent our only probe of the local halo on sub-milliparsec scales. This is best achieved in the case of WIMP dark matter if directionally sensitive experiments are feasible, but requires novel parameterizations of the velocity distribution to make model independent claims. For axions the prospects are much greater, haloscopes would be able to make better measurements of the local DM distribution than astrometric probes.

    ↳ astro-ph.COhep-ph1 citation
38. 38*

    (Non-)thermal production of WIMPs during kination

    Luca Visinelli🇸🇪

    Understanding the nature of the Dark Matter (DM) is one of the current challenges in modern astrophysics and cosmology. Knowing the properties of the DM particle would shed light on physics beyond the Standard Model and even provide us with details of the early Universe. In fact, the detection of such a relic would bring us information from the pre-Big Bang Nucleosynthesis (BBN) period, an epoch from which we have no data, and could even hint at inflationary physics. In this work, we assume that the expansion rate of the Universe after inflationary is governed by the kinetic energy of a scalar field $\varphi$, in the so-called "kination" model. We assume that the $\varphi$ field decays into both radiation and DM particles, which we take to be Weakly Interacting Massive Particles (WIMPs). The present abundance of WIMPs is then fixed during the kination period through either a thermal "freeze-out" or "freeze-in" mechanism, or through a non-thermal process governed by the decay of $\varphi$. We explore the parameter space of this theory with the requirement that the present WIMP abundance provides the correct DM relic budget. Requiring that BBN occurs during the standard cosmological scenario sets a limit on the temperature at which the kination period ends. Using this limit and assuming the WIMP has a mass $m_{\chi }=100$GeV, we obtain that the thermally-averaged WIMP annihilation cross section has to satisfy the constraints $4\times 10^{-16}\mathrm{Ge}{\mathrm{V}}^{-2}\lesssim ⟨\sigma v⟩\lesssim 2\times 10^{-5}\mathrm{Ge}{\mathrm{V}}^{-2}$ in order for having at least one of the production mechanism to yield the observed amount of DM. This result shows how the properties of the WIMP particle, if ever measured, can yield information on the pre-BBN content of the Universe.

    ↳ astro-ph.COhep-phSymmetry(2018)·71 citations
39. 39*

    Lattice calculation of hadronic tensor of the nucleon

    Jian Liang🇺🇸 · Keh-Fei Liu🇺🇸 · Yi-Bo Yang🇺🇸

    We report an attempt to calculate the deep inelastic scattering structure functions from the hadronic tensor calculated on the lattice. We used the Backus-Gilbert reconstruction method to address the inverse Laplace transformation for the analytic continuation from the Euclidean to the Minkowski space.

    ↳ hep-lathep-phnucl-thEPJ Web Conf.(2018)·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.