Wed·Oct 18, 2017Wednesday·October 18, 2017

1. 01*

   Angular distributions in pion-nucleon Drell-Yan process

   I. V. Anikin🇷🇺 · L. Szymanowski🇵🇱 · O. V. Teryaev🇷🇺 · N. Volchanskiy🇷🇺

   We study the Drell-Yan process in the polarized pion-nucleon scattering. We calculate the $U(1{)}_{\text{em}}$ gauge invariant hadron tensors. To this end, we have to take into account two diagrams---the standard diagram and an additional one---both diagrams are required to get the gauge invariant hadron tensor. We obtain a new single transverse spin asymmetry that probes gluon poles and chiral-odd distribution functions. The process of pion-nucleon scattering in the limit of large Feynman $x$ is described by a convolution of two non-collinear exclusive-channel distribution amplitudes, which demonstrates the duality between different factorization regimes.

   hep-phJ.Phys.Conf.Ser.(2017)·1 citation
2. 02*

   Probing the BFKL dynamics in the Vector Meson Photoproduction at large -- $t$ in $pPb$ collisions at the CERN LHC

   V. P. Goncalves🇧🇷 · W. K. Sauter🇧🇷

   The photoproduction of vector mesons in $pPb$ collisions at LHC energies is investigated assuming that the color singlet $t$-channel exchange carries a large momentum transfer $t$. The rapidity distributions and total cross sections for the process $Pbp\to Pb\otimes V\otimes jet+X$, with $V=\rho ,J/\Psi$ and $\otimes$ representing a rapidity gap in the final state, are estimated considering the non-forward solution of the BFKL equation at high energy and large -- $t$. A comparison with the predictions obtained at the Born level also is presented. We predict a large enhancement of the cross sections associated to the BFKL dynamics in the kinematical range probed by the LHCb Collaboration. Moreover, our results indicate that the experimental identification can be feasible at the LHC and that this process can be used to probe the BFKL dynamics.

   hep-phhep-exPLB(2018)·2 citations
3. 03*

   NMSSM From Alternative Deflection in Generalized Deflected Anomaly Mediated SUSY Breaking

   Xiaokang Du🇨🇳 · Fei Wang🇨🇳

   We propose a new approach to generate messenger-matter interactions in deflected anomaly mediated SUSY breaking mechanism from typical holomorphic messenger-matter mixing terms in the Kahler potential. This approach is a unique feature of AMSB and has no analog in GMSB-type scenarios. New coupling strengths from the scaling of the (already known) Yukawa couplings always appear in this approach. With messenger-matter interactions in deflected AMSB, we can generate a realistic soft SUSY breaking spectrum for next-to-minimal supersymmetric standard model(NMSSM). Successful electroweak symmetry breaking conditions, which is not easy to satisfy in NMSSM for ordinary AMSB-type scenario, can be satisfied in a large portion of parameter space in our scenarios. We study the relevant phenomenology for scenarios with (Bino-like) neutralino and axino LSP, respectively. In the case of axino LSP, the SUSY contributions to $\Delta a_{\mu }$ can possibly account for the muon $g-2$ discrepancy. The corresponding gluino masses, which are found to below 2.2 TeV, could be tested soon at LHC.

   hep-phEPJC(2018)·15 citations
4. 04*

   Majorana neutrino signals at Belle-II and ILC

   Chong-Xing Yue🇨🇳 · Yu-Chen Guo🇨🇳 · Zhen-Hua Zhao🇨🇳

   For some theoretical and experimental considerations, the relatively light Majorana neutrinos at the GeV scale have been attracting some interest. In this article we consider a scenario with only one Majorana neutrino $N$, negligible mixing with the active neutrinos ${\nu }_L$, where the Majorana neutrino interactions could be described in a model independent approach based on an effective theory. Under such a framework, we particularly study the feasibility of observing the $N$ with mass in the range 0$-$30 GeV via the process $e^{+}{e}^{-}\to \nu N\to \gamma +\text{slashed}E$ in the future Belle-II and ILC experiments. The results show that it is unpromising for Belle-II to observe the signal, while ILC may easily make a discovery for the Majorana neutrino.

   hep-phNPB(2017)·13 citations
5. 05*

   Conformal Standard Model, Leptogenesis and Dark Matter

   Adrian Lewandowski (1)🇩🇪 · Krzysztof A. Meissner (2)🇵🇱 · Hermann Nicolai (1) ((1) Max-Planck-Institut für Gravitationsphysik, Potsdam, (2) Faculty of Physics, University of Warsaw)🇩🇪

   The Conformal Standard Model (CSM) is a minimal extension of the Standard Model of Particle Physics based on the assumed absence of large intermediate scales between the TeV scale and the Planck scale, which incorporates only right-chiral neutrinos and a new complex scalar in addition to the usual SM degrees of freedom, but no other features such as supersymmetric partners. In this paper, we present a comprehensive quantitative analysis of this model, and show that all outstanding issues of particle physics proper can in principle be solved `in one go' within this framework. This includes in particular the stabilization of the electroweak scale, `minimal' leptogenesis and the explanation of Dark Matter, with a small mass and very weakly interacting Majoron as the Dark Matter candidate (for which we propose to use the name `minoron'). The main testable prediction of the model is a new and almost sterile scalar boson that would manifest itself as a narrow resonance in the TeV region. We give a representative range of parameter values consistent with our assumptions and with observation.

   hep-phhep-thPRD(2018)·21 citations
6. 06*

   Left Right Symmetric Models with a Mixture of keV-TeV Dark Matter

   Debasish Borah🇮🇳 · Arnab Dasgupta🇮🇳

   We discuss the possibility of realising a multi-component dark matter scenario with widely separated dark matter masses: one having keV scale mass and the other with GeV-TeV scale mass, within the framework of left right symmetric models. Due to gauge interactions, both the dark matter candidates are produced thermally in the early Universe but overproducing the keV mass candidate. We consider one of the right handed neutrinos to be decaying at late epochs, just before the big bang nucleosynthesis, in order to dilute the thermally overproduced keV dark matter. We constrain the parameter space from the requirement of producing sub-dominant keV-TeV dark matter, satisfying indirect detection constraints from gamma ray searches and producing the tantalising 3.55 keV monochromatic X-ray line, reported by several groups to be present in galaxy and galaxy cluster data, from the decay of a 7.1 keV dark matter on cosmological scales. We find that these requirements can keep the right sector gauge boson masses around a few TeV while requiring some of the right-handed neutrinos in the sub-GeV regime.

   hep-phastro-ph.COJ.Phys.G(2019)·16 citations
7. 07*

   Non-perturbative study of spectral function and its application in Quark Gluon Plasma

   Aritra Bandyopadhyay🇮🇳

   The thesis contains studies of properties quark-gluon plasma, using some non-perturbative techniques. It contains a brief introduction of quark-gluon plasma (QGP) and discussion on various signatures along with a motivation for this thesis work. It presents the basic mathematical tools and ingredients required for the thesis, i.e. basics of QCD, Imaginary and Real Time Formalism, Hard Thermal Loop perturbation theory (HTLpt), Gribov-Zwanziger (GZ) action, the Correlation Function along with the Spectral Function and Operator Product Expansion (OPE) and QCD in magnetized medium. OPE is used to compute the dilepton rate in intermediate mass range by incorporating the non-perturbative dynamics of QCD through the inclusion of non-vanishing quark and gluon condensates in combination with the Green functions in momentum space. Also the magnetic scale (g^2T) in the HTL perturbation theory, related to the confining properties of the QCD is taken into account using the GZ action through a mass parameter, which reflects a new space-like quark mode in the collective excitation. The impact of this new exciting mode on the DPR has been studied and its important consequences has been discussed. A hot magnetized medium introduces another scale in the system in addition to temperature. Electromagnetic spectral properties and DPR are studied completely analytically in presence of both strong and weak background magnetic fields at finite temperature. The Debye screening in a hot and magnetized medium has been studied which reveals some of the intriguing properties of the medium in presence of both strong and weak magnetic field. Also an important quantity that characterizes the QGP, namely quark number susceptibility has been investigated. Most of the non-perturbative results discussed in this thesis are compared with those of perturbative ones and lattice QCD.

   hep-phhep-latnucl-th1 citation
8. 08*

   Quasi Dirac neutrino oscillations

   G. Anamiati🇪🇸 · R. M. Fonseca🇪🇸 · M. Hirsch🇪🇸

   Dirac neutrino masses require two distinct neutral Weyl spinors per generation, with a special arrangement of masses and interactions with charged leptons. Once this arrangement is perturbed, lepton number is no longer conserved and neutrinos become Majorana particles. If these lepton number violating perturbations are small compared to the Dirac mass terms, neutrinos are quasi-Dirac particles. Alternatively, this scenario can be characterized by the existence of pairs of neutrinos with almost degenerate masses, and a lepton mixing matrix which has 12 angles and 12 phases. In this work we discuss the phenomenology of quasi-Dirac neutrino oscillations and derive limits on the relevant parameter space from various experiments. In one parameter perturbations of the Dirac limit, very stringent bounds can be derived on the mass splittings between the almost degenerate pairs of neutrinos. However, we also demonstrate that with suitable changes to the lepton mixing matrix, limits on such mass splittings are much weaker, or even completely absent. Finally, we consider the possibility that the mass splittings are too small to be measured and discuss bounds on the new, non-standard lepton mixing angles from current experiments for this case.

   hep-phPRD(2018)·40 citations
9. 09*

   Overview of top quark physics at the ep colliders

   Hao Sun🇨🇳

   In this talk we present a short overview of top physics at the electron-proton (ep) colliders. Currently, the proposed ep collider is the Large Hadron Electron Collider (LHeC), which is a combination of 60 GeV electron beam and 7 TeV proton beam of the LHC tunnel. This may be extended to Future Circular electron-hadron Collider (FCC-eh), which features a 60 GeV (or higher) electron beam with the 50 TeV proton beam from the Future Circular hadron Collider (FCC-hh). Selected topics include but not limited to top structure function, top parton distribution functions, top spin polarization, top electric charge, measurement of ${\mathrm{V}}_{\mathrm{tb}}$, anomalous $\mathrm{tt}\gamma$, ttZ, tbW, $\mathrm{tq}\gamma$, tqH couplings and CP phase of ttH coupling.

   hep-phPoS(2018)·8 citations
10. 10*

    Searching for the doubly-charged Higgs bosons in the Georgi-Machacek model at the ep colliders

    Hao Sun🇨🇳 · Xuan Luo🇨🇳

    The Georgi-Machacek model is one of many beyond Standard Model scenarios with an extended scalar sector which can group under the custodial $\mathrm{SU}(2{)}_{\mathrm{C}}$ symmetry. There are 5-plet, 3-plet and singlet Higgs bosons under the classification of such symmetry in addition to the Standard Model Higgs boson. Here we study the prospects for detecting the doubly-charged Higgs boson (${\mathrm{H}}_5^{\pm \pm }$) through the vector boson fusion production at the electron-proton colliders. Typically, we concentrate on our analysis through $\mu$-lepton pair production via pair of same-sign W bosons decay. The discovery significance are calculated as the functions of the triplet vacuum expectation value and necessary luminosity.

    hep-phPoS(2018)·0 citations
11. 11*

    Searching for the doubly-charged Higgs bosons in the Georgi-Machacek model at the electron-proton colliders

    Hao Sun🇨🇳 · Xuan Luo🇨🇳 · Wei Wei🇨🇳 · Tong Liu🇨🇳

    The Georgi-Machacek model is one of many beyond Standard Model scenarios with an extended scalar sector which can group under the custodial $\mathrm{SU}(2{)}_{\mathrm{C}}$ symmetry. There are 5-plet, 3-plet and singlet Higgs bosons under the classification of such symmetry in addition to the Standard Model Higgs boson. In this paper, we study the prospects for detecting the doubly-charged Higgs boson (${\mathrm{H}}_5^{\pm \pm }$) through the vector boson fusion production at the electron-proton (ep) colliders. We concentrate on our analysis through $\mu$-lepton pair production via pair of same-sign W bosons decay. The ${\mathrm{H}}_5^{\pm \pm }$ discovery potentials at the ep colliders are presented.

    hep-phPRD(2017)·25 citations
12. 12*

    NNLO predictions for Z-boson pair production at the LHC

    G. Heinrich🇩🇪 · S. Jahn🇩🇪 · S.P. Jones🇩🇪 · M. Kerner🇩🇪 · Joao Pires🇩🇪

    We present a calculation of the NNLO QCD corrections to Z-boson pair production at hadron colliders, based on the N-jettiness method for the real radiation parts. We discuss the size and shape of the perturbative corrections along with their associated scale uncertainties and compare our results to recent LHC data at $\sqrt{s}=13$ TeV.

    hep-phJHEP(2018)·62 citations
13. 13*

    Double Parton Scattering of Weak Gauge Boson Productions at the 13 TeV and 100 TeV Proton-Proton Colliders

    Qing-Hong Cao🇨🇳 · Yandong Liu🇨🇳 · Ke-Pan Xie🇨🇳 · Bin Yan🇺🇸

    We study double parton scattering (DPS) processes involving electroweak gauge bosons at the 13 TeV and 100 TeV proton-proton colliders. Specifically, we focus on three DPS channels: $W$-boson plus two jets ($W\otimes jj$), $Z$-boson plus two jets ($Z\otimes jj$), and same-sign $W$ pair production ($W^{\pm }\otimes W^{\pm }$). We demonstrate that the $Z\otimes jj$ process, which has not been paid too much attentions, is the best channel for measuring effective cross section ${\sigma }_{\mathrm{eff}}$. The accuracy of ${\sigma }_{\mathrm{eff}}$ measurement in the three DPS channels, especially the $W^{\pm }\otimes W^{\pm }$ production, is significantly improved at the 100 TeV colliders. We advocate that combined analysis of the three DPS channels could test the universality of effective cross section ${\sigma }_{\mathrm{eff}}$.

    hep-phhep-exPRD(2018)·17 citations
14. 14*

    Quark-antiquark antenna splitting in a medium

    Fabio Dominguez🇪🇸 · Carlos A Salgado🇪🇸 · Victor Vila🇪🇸

    We study a system in which a quark-antiquark antenna emits a hard gluon in a medium, and an extra very soft emission afterwards. Considering the coherence effects in terms of the survival probability, we can describe the interaction of the $q\bar{q}g$ configuration with the medium. We extrapolate previous analyzes of the antenna radiation to the case of two hard splittings inside the medium, and prove that this generalization keeps back the picture of jet quenching with effective emitters in the parton QCD cascade.

    hep-phnucl-thPoS(2018)·0 citations
15. 15*

    Revised neutrino-gallium cross section and prospects of BEST in resolving the Gallium anomaly

    Vladislav Barinov🇷🇺 · Bruce Cleveland🇨🇦 · Vladimir Gavrin🇷🇺 · Dmitry Gorbunov🇷🇺 · Tatiana Ibragimova🇷🇺

    O(1) eV sterile neutrino can be responsible for a number of anomalous results of neutrino oscillation experiments. This hypothesis may be tested at short base-line neutrino oscillation experiments, several of which are either ongoing or under construction. Here we concentrate on the so-called Gallium anomaly, found by SAGE and GALLEX experiments, and its foreseeable future tests with BEST experiment at Baksan Neutrino Observatory. We start with a revision of the neutrino-gallium cross section, that is performed by utilizing the recent measurements of the nuclear final state spectra. We accordingly correct the parameters of Gallium anomaly and refine the BEST prospects in testing it and searching for sterile neutrinos. We further evolve the previously proposed idea to investigate the anomaly with Zn-65 artificial neutrino source as a next option available at BEST, and estimate its sensitivity to the sterile neutrino model parameters following the Bayesian approach. We show that after the two stages of operation BEST will make 5$\sigma$-discovery of the sterile neutrinos, if they are behind the Gallium anomaly.

    hep-phhep-exnucl-exnucl-thPRD(2018)·41 citations
16. 16*

    Phenomenology of leading nucleon production in $ep$ collisions at HERA in the framework of fracture functions

    Samira Shoeibi🇮🇷 · F. Taghavi-Shahri🇮🇷 · Hamzeh Khanpour🇮🇷 · Kurosh Javidan🇮🇷

    In recent years, several experiments at the $e^{-}p$ collider HERA have collected high precision deep inelastic scattering (DIS) data on the spectrum of leading nucleon carrying a large fraction of the proton's energy. In this paper, we have analyzed recent experimental data on the production of forward proton and neutron in DIS at HERA in the framework of a perturbative QCD. We propose a technique based on the fractures functions framework, and extract the nucleon fracture functions (nucleon FFs) ${\mathcal{M}}_2^{(n/p)}(x,Q^2;x_L)$ from global QCD analysis of DIS data measured by ZEUS collaboration at HERA. We have shown that an approach based on the fracture functions formalism allows us phenomenologically parametrize the nucleon FFs. Considering both leading neutron as well as leading proton production data at HERA, we present the results for the separate parton distributions for all parton species, including valence quark densities, the anti-quark densities, the strange sea distribution, and the gluon distribution functions. We proposed several parameterizations for the nucleon FFs and open the possibility of these asymmetries. The obtained optimum set of nucleon FFs is accompanied by Hessian uncertainty sets which allow one to propagate uncertainties to other observables interest. The extracted results for the $t$-integrated leading neutron $F_2^{\mathrm{LN}(3)}(x,Q^2;x_L)$ and leading proton $F_2^{\mathrm{LP}(3)}(x,Q^2;x_L)$ structure functions are in good agreement with all data analyzed, for a wide range of fractional momentum variable $x$ as well as the longitudinal momentum fraction $x_L$.

    hep-phhep-exPRD(2018)·18 citations
17. 17*

    Physics at the FCC-hh, a 100 TeV pp collider

    Michelangelo Mangano (ed.) (CERN)🇨🇭

    A 100 TeV pp collider is under consideration, by the high-energy physics community, as an important step for the future development of our field, following the completion of the LHC and High-luminosity LHC physics programmes. In particular, CERN is considering 100 TeV pp collisions as the key target of a Future Circular Collider facility, built around a 100 km tunnel and designed to deliver pp, e+e- and ep collisions, in addition to a programme with heavy ion beams and with the injector complex. CERN is coordinating an international study tasked with the completion, by the end of 2018, of a Conceptual Design Report (CDR) for this facility. This document presents the first results of the assessment of the physics potential of the hadronic part of this research programme (FCC-hh).

    hep-phCERN Yellow Report CERN 2017-003-M·124 citations
18. 18*

    Improving predictions for associated $t\bar{t}H$ production at the LHC: soft gluon resummation through NNLL accuracy

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

    In the following we present our recent results on the resummation of soft gluon corrections to the $pp\to t\bar{t}H$ cross section at the LHC. The resummation was carried out at next-to-next-to-leading-logarithmic (NNLL) accuracy using the Mellin space technique. Obtained results were matched to the NLO cross section. We show that the resummation leads to reduction of scale-variation uncertainty of the total $pp\to t\bar{t}H$ cross section.

    hep-phPoS(2017)·3 citations
19. 19*

    The Case for Future Hadron Colliders From $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$ Decays

    B.C. Allanach🇬🇧 · Ben Gripaios🇬🇧 · Tevong You🇬🇧

    Recent measurements in $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$ decays are somewhat discrepant with Standard Model predictions. They may be harbingers of new physics at an energy scale potentially accessible to direct discovery. We estimate the sensitivity of future hadron colliders to the possible new particles that may be responsible for the anomalies: leptoquarks or $Z^{\prime }$s. We consider luminosity upgrades for a 14 TeV LHC, a 33 TeV LHC, and a 100 TeV $pp$ collider such as the FCC-hh. Coverage of $Z^{\prime }$ models is excellent: for narrow particles, with perturbative couplings that may explain the $b$-decay results for $Z^{\prime }$ masses up to 20 TeV, a 33 TeV 1 ab${}^{-1}$ LHC is expected to cover most of the parameter space up to 8 TeV in mass, whereas the 100 TeV FCC-hh with 10 ab${}^{-1}$ will cover all of it. A smaller portion of the leptoquark parameter space is covered by future colliders: for example, in a ${\mu }^{+}{\mu }^{-}jj$ di-leptoquark search, a 100 TeV 10 ab${}^{-1}$ collider has a projected sensitivity up to leptoquark masses of 12 TeV (extendable to 21 TeV with a strong coupling for single leptoquark production), whereas leptoquark masses up to 41 TeV may in principle explain the anomalies.

    hep-phhep-exJHEP(2018)·64 citations
20. 20*

    Complete One-Loop Renormalization of the Higgs-Electroweak Chiral Lagrangian

    G. Buchalla🇩🇪 · O. Cata🇩🇪 · A. Celis🇩🇪 · M. Knecht🇫🇷 · C. Krause🇪🇸

    Employing background-field method and super-heat-kernel expansion, we compute the complete one-loop renormalization of the electroweak chiral Lagrangian with a light Higgs boson. Earlier results from purely scalar fluctuations are confirmed as a special case. We also recover the one-loop renormalization of the conventional Standard Model in the appropriate limit.

    hep-phNPB(2018)·78 citations
21. 21*

    Discrete Dark Matter Model and Reactor Mixing Angle

    J. M. Lamprea🇲🇽

    We present a scenario where the stability of dark matter and the phenomenology of neutrinos are related by the breaking of a flavour symmetry. We propose two models based on this idea for which we have obtained interesting neutrino and dark matter phenomenology.

    hep-phFrascati Phys.Ser.(2016)·0 citations
22. 22*

    Nucleon form factors in dispersively improved Chiral Effective Field Theory II: Electromagnetic form factors

    J. M. Alarcón🇺🇸 · C. Weiss🇺🇸

    We study the nucleon electromagnetic form factors (EM FFs) using a recently developed method combining Chiral Effective Field Theory ($\chi$EFT) and dispersion analysis. The spectral functions on the two-pion cut at $t>4M_{\pi }^2$ are constructed using the elastic unitarity relation and an $N/D$ representation. $\chi$EFT is used to calculate the real functions $J_{\pm }^1(t)=f_{\pm }^1(t)/F_{\pi }(t)$ (ratios of the complex $\pi \pi \to N\bar{N}$ partial-wave amplitudes and the timelike pion FF), which are free of $\pi \pi$ rescattering. Rescattering effects are included through the empirical timelike pion FF $|F_{\pi }(t){|}^2$. The method allows us to compute the isovector EM spectral functions up to $t\sim 1$ GeV${}^2$ with controlled accuracy (LO, NLO, and partial N2LO). With the spectral functions we calculate the isovector nucleon EM FFs and their derivatives at $t=0$ (EM radii, moments) using subtracted dispersion relations. We predict the values of higher FF derivatives with minimal uncertainties and explain their collective behavior. We estimate the individual proton and neutron FFs by adding an empirical parametrization of the isoscalar sector. Excellent agreement with the present low-$Q^2$ FF data is achieved up to $\sim$0.5 GeV${}^2$ for $G_E$, and up to $\sim$0.2 GeV${}^2$ for $G_M$. Our results can be used to guide the analysis of low-$Q^2$ elastic scattering data and the extraction of the proton charge radius.

    hep-phhep-latnucl-exnucl-thPRC(2018)·37 citations
23. 23*

    Electroweak-Charged Bound States as LHC Probes of Hidden Forces

    Lingfeng Li🇺🇸 · Ennio Salvioni🇩🇪 · Yuhsin Tsai🇺🇸 · Rui Zheng🇺🇸

    We explore the LHC reach on beyond-the-Standard Model (BSM) particles $X$ associated with a new strong force in a hidden sector. We focus on the motivated scenario where the SM and hidden sectors are connected by fermionic mediators ${\psi }^{+,0}$ that carry SM electroweak charges. The most promising signal is the Drell-Yan production of a ${\psi }^{\pm }{\bar{\psi }}^0$ pair, which forms an electrically charged vector bound state ${{\rm Y}}^{\pm }$ due to the hidden force and later undergoes resonant annihilation into $W^{\pm }X$. We analyze this final state in detail in the cases where $X$ is a real scalar $\varphi$ that decays to $b\bar{b}$, or a dark photon ${\gamma }_d$ that decays to dileptons. For prompt $X$ decays, we show that the corresponding signatures can be efficiently probed by extending the existing ATLAS and CMS diboson searches to include heavy resonance decays into BSM particles. For long-lived $X$, we propose new searches where the requirement of a prompt hard lepton originating from the $W$ boson ensures triggering and essentially removes any SM backgrounds. To illustrate the potential of our results, we interpret them within two explicit models that contain strong hidden forces and electroweak-charged mediators, namely $\lambda$-supersymmetry (SUSY) and non-SUSY ultraviolet extensions of the Twin Higgs model. The resonant nature of the signals allows for the reconstruction of the mass of both ${{\rm Y}}^{\pm }$ and $X$, thus providing a wealth of information about the hidden sector.

    hep-phhep-exPRD(2018)·13 citations
24. 24*

    MatchingTools: a Python library for symbolic effective field theory calculations

    Juan C. Criado🇪🇸

    MatchingTools is a Python library for doing symbolic calculations in effective field theory. It provides the tools to construct general models by defining their field content and their interaction Lagrangian. Once a model is given, the heavy particles can be integrated out at the tree level to obtain an effective Lagrangian in which only the light particles appear. After integration, some of the terms of the resulting Lagrangian might not be independent. MatchingTools contains functions for transforming these terms to rewrite them in terms of any chosen set of operators.

    hep-phComput.Phys.Commun.(2018)·76 citations
25. 25*

    Gluon and ghost correlation functions of 2-color QCD at finite density

    Ouraman Hajizadeh🇦🇹 · Tamer Boz🇮🇪 · Axel Maas🇦🇹 · Jon-Ivar Skullerud🇮🇪

    2-color QCD, i. e. QCD with the gauge group SU(2), is the simplest non-Abelian gauge theory without sign problem at finite quark density. Therefore its study on the lattice is a benchmark for other non-perturbative approaches at finite density. To provide such benchmarks we determine the minimal-Landau-gauge 2-point and 3-gluon correlation functions of the gauge sector and the running gauge coupling at finite density. We observe no significant effects, except for some low-momentum screening of the gluons at and above the supposed high-density phase transition.

    ↳ hep-lathep-phEPJ Web Conf.(2018)·13 citations
26. 26*

    Intra-cone transition effect to magnetoconductivity in Dirac semimetal

    Aya Kagimura🇯🇵 · Tetsuya Onogi🇯🇵

    We study the transport of the fermions with a small mass in the presence of Coulomb impurities, which could be realized in slightly distorted Dirac semimetals. Using the semiclassical Boltzmann equation, we derive the relaxation times for two kinds of intra-cone transition process. One is due to the effect of mass, and the other is due to the excited states in Landau levels under the weaker magnetic field. Hence we derive the mass dependence and the magnetic field dependence of the longitudinal magnetoconductivity in the presence of parallel electric and magnetic fields.

    ↳ cond-mat.mes-hallhep-phJHEP(2017)·0 citations
27. 27*

    HVP contributions to the muon ($g-2$) including QED corrections with twisted-mass fermions

    D. Giusti🇮🇹 · V. Lubicz🇮🇹 · G. Martinelli🇮🇹 · F. Sanfilippo🇮🇹 · S. Simula🇮🇹

    We present a lattice calculation of the Hadronic Vacuum Polarization (HVP) contribution of the strange and charm quarks to the anomalous magnetic moment of the muon including leading-order electromagnetic (e.m.) corrections. We employ the gauge configurations generated by the European Twisted Mass Collaboration (ETMC) with $N_f=2+1+1$ dynamical quarks at three values of the lattice spacing ($a\simeq 0.062,0.082,0.089$ fm) with pion masses in the range $M_{\pi }\simeq 210-450$ MeV. The strange and charm quark masses are tuned at their physical values. Neglecting disconnected diagrams and after the extrapolations to the physical pion mass and to the continuum limit we obtain: $a_{\mu }^s({\alpha }_{em}^2)=(53.1\pm 2.5)\cdot 10^{-10}$, $a_{\mu }^s({\alpha }_{em}^3)=(-0.018\pm 0.011)\cdot 10^{-10}$ and $a_{\mu }^c({\alpha }_{em}^2)=(14.75\pm 0.56)\cdot 10^{-10}$, $a_{\mu }^c({\alpha }_{em}^3)=(-0.030\pm 0.013)\cdot 10^{-10}$ for the strange and charm contributions, respectively.

    ↳ hep-lathep-phEPJ Web Conf.(2018)·2 citations
28. 28*

    Spectrum of QCD at Finite Isospin Density

    Philipp Scior🇩🇪 · Lorenz von Smekal🇩🇪 · Dominik Smith🇩🇪

    We study the phase diagram of QCD at finite isospin density using two flavors of staggered quarks. We investigate the low temperature region of the phase diagram where we find a pion condensation phase at high chemical potential. We started a basic analysis of the spectrum at finite isospin density. In particular, we measured pion, rho and nucleon masses inside and outside of the pion condensation phase. In agreement with previous studies in two-color QCD at finite baryon density we find that the Polyakov loop does not depend on the density in the staggered formulation.

    ↳ hep-lathep-phnucl-thEPJ Web Conf.(2018)·10 citations
29. 29*

    First cosmological constraints combining Planck with the recent gravitational-wave standard siren measurement of the Hubble constant

    Eleonora Di Valentino🇬🇧 · Alessandro Melchiorri🇮🇹

    The recent observations of gravitational-wave and electromagnetic emission produced by the merger of the binary neutron-star system GW170817 have opened the possibility of using standard sirens to constrain the value of the Hubble constant. While the reported bound of $H_0=70_{-8}^{+12}$ at $68\%$ C.L. is significantly weaker than those recently derived by observations of Cepheid variables, it does not require any form of cosmic distance ladder and can be considered as complementary and, in principle, more conservative. Here we combine, for the first time, the new measurement with the Planck Cosmic Microwave Background observations in a $12$ parameters extended $\Lambda$CDM scenario, where the Hubble constant is weakly constrained from CMB data alone and bound to a low value $H_0=55_{-20}^{+7}$ km/s/Mpc at $68\%$ C.L. We point out that the non-Gaussian shape of the GW170817 bound makes lower values of the Hubble constant in worst agreement with observations than what expected from a Gaussian form. The inclusion of the new GW170817 Hubble constant measurement therefore significantly reduces the allowed parameter space, improving the cosmological bounds on several parameters as the neutrino mass, curvature and the dark energy equation of state.

    ↳ astro-ph.COgr-qchep-phPRD(2018)·22 citations
30. 30*

    Constraints from the Time Lag between Gravitational Waves and Gamma Rays: Implications of GW 170817 and GRB 170817A

    Ian M. Shoemaker🇺🇸 · Kohta Murase🇺🇸

    The Laser Interferometer Gravitational-Wave Observatory (LIGO) has recently discovered gravitational waves (GWs) from its first neutron star-neutron star merger at a distance of $\sim 40$~Mpc from the Earth. The associated electromagnetic (EM) detection of the event, including the short gamma-ray burst within $\Delta t\sim 2$~s after the GW arrival, can be used to test various aspects of sources physics and GW propagation. Using GW170817 as the first GW-EM example, we show that this event provides a stringent direct test that GWs travel at the speed of light. The gravitational potential of the Milky Way provides a potential source of Shapiro time delay difference between the arrival of photons and GWs, and we demonstrate that the nearly coincident detection of the GW and EM signals can yield strong limits on anomalous gravitational time delay, through updating the previous limits taking into account details of Milky Way's gravitational potential. Finally, we also obtain an intriguing limit on the size of the prompt emission region of GRB 170817A, and discuss implications for the emission mechanism of short gamma-ray bursts.

    ↳ astro-ph.HEgr-qchep-phPRD(2018)·41 citations

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