Fri·Jun 15, 2018Friday·June 15, 2018

1. 01*

   Charge-dependent Flow Induced by Magnetic and Electric Fields in Heavy Ion Collisions

   Umut Gürsoy🇳🇱 · Dmitri Kharzeev🇺🇸 · Eric Marcus🇳🇱 · Krishna Rajagopal🇺🇸 · Chun Shen🇺🇸

   We investigate the charge-dependent flow induced by magnetic and electric fields in heavy ion collisions. We simulate the evolution of the expanding cooling droplet of strongly coupled plasma hydrodynamically, using the iEBE-VISHNU framework, and add the magnetic and electric fields as well as the electric currents they generate in a perturbative fashion. We confirm the previously reported effect of the electromagnetically induced currents, that is a charge-odd directed flow $\Delta v_1$ that is odd in rapidity, noting that it is induced by magnetic fields (à la Faraday and Lorentz) and by electric fields (the Coulomb field from the charged spectators). In addition, we find a charge-odd $\Delta v_3$ that is also odd in rapidity and that has a similar physical origin. We furthermore show that the electric field produced by the net charge density of the plasma drives rapidity-even charge-dependent contributions to the radial flow $⟨p_T⟩$ and the elliptic flow $\Delta v_2$. Although their magnitudes are comparable to the charge-odd $\Delta v_1$ and $\Delta v_3$, they have a different physical origin, namely the Coulomb forces within the plasma.

   hep-phhep-thnucl-exnucl-thPRC(2018)·128 citations
2. 02*

   Nambu Jona Lasinio model with proper time regularization in a finite volume

   Qingwu. Wang🇨🇳 · Yonghui. Xiq🇨🇳 · Hongshi. Zong🇨🇳

   Based on the two flavor NJL model with a proper time regularization, we used stationary wave condition (SWC) for the first time to study the influence of the finite volume effects on the chiral phase transition of quark matter at finite temperature. It is found that when the cubic volume size L is large than LSWC = 500 fm, the chiral quark condensate is indistinguishable from that max at L = $\text{infinity}$,Here it should be noted that 500 fm is far greater than the size of QGP produced at laboratory and the lattice QCD simulation space size. It is also much larger than the previous limit size LAPBC = 5 fm estimated by the commonly used anti-periodic boundary condition (APBC). max We also found that when the space size L is less than LSWC = 0.25 fm, the spontaneous symmetry min breaking concept is no longer valid. In addition, we first introduce the spatial susceptibility, and through the study of the spatial susceptibility, it was revealed for the first time that the chiral phase transition caused by the finite volume effects in the nonchiral limit is a crossover.

   hep-phMod.Phys.Lett.A(2018)·34 citations
3. 03*

   Masses and Strong Decay properties of Radially Excited Bottom states B(2S)and B(2P) with their Strange Partners Bs(2S) and Bs(2P)

   Pallavi Gupta🇮🇳 · A. Upadhyay

   In this paper, we analyzed the experimentally available radially excited charm mesons to predict the similar spectra for the n=2 bottom mesons. In the heavy quark effective theory, we explore the flavor independent parameters to calculate the masses for the experimentally unknown n=2 bottom mesons B(2S), B(2P), Bs(2S) and Bs(2P). We have also analyzed these bottom masses by applying the QCD and 1/mQ corrections to the lagrangian leading to the modification of flavor symmetry parameters as. Further strong decay widths are determined using these calculated masses to check the sensitivity of these corrections for these radially excited mesons. The calculated decay widths are in the form of strong coupling constant geHH, egSH and egTH. We concluded that these corrections are less sensitive for n=2 masses as compared to n=1 masses. Branching ratios and branching fractions of these states are calculated to have a deeper understanding of these states. These predicted values can be confronted with the future experimental data.

   hep-phEPJA(2018)·5 citations
4. 04*

   Open- and hidden-charm tetra-quark scalar mesons

   Kunihiko Terasaki🇯🇵

   Masses of open- and hidden-charm tetra-quark scalar mesons are studied in a new approach. As the result, newly estimated masses of hidden-charm sector are significantly lower than our earier ones by a naive quark counting. In particular, our new result on the non-strange iso-triplet scalar mesons should be compared with the experiment that an indication of tiny eta pi peak around 3.2 GeV has been observed, while no signal in the eta_c pi channel.

   hep-ph0 citations
5. 05*

   $\Xi$(2030) and $\Xi$(2120) as ${\bar{K}}^{\ast }\Sigma$ molecular states

   Yin Huang🇨🇳 · Rong Wang🇫🇷 · Jun He🇨🇳 · Ju-Jun Xie🇨🇳 · Lisheng Geng🇨🇳

   In this work, the molecular states from the \bar{K}^{*}\Sigma interaction are studied in a quasipotential Bethe-Salpeter equation approach with the one-boson-exchange potentials. We consider the exchanges of vector (\rho,\omega and \phi) mesons and pseudoscalar (\pi and \eta) mesons to describe the \bar{K}^{*}\Sigma interaction with the coupling constants determined by the SU(3) symmetry, The poles of the scattering amplitude are searched for to find the molecular states dynamically generated from the \bar{K}^{*}\Sigma interaction. A bound state with quantum number I(J^{p})=1/2(5/2^{+}) is produced, which can be associated to the \Xi(2030) baryon. Other bound states with J\le{}5/2 are also searched for and it is found that there exist bound states with quantum numbers I(J^P)=1/2(1/2^-), 1/2(3/2^{-}), and 1/2(3/2^+). The \Xi(2120) may be a candidate for one of these three bound states. In addition, we also find two bound states with isospin 3/2 and spin parities 1/2^- and 1/2^+.

   hep-phnucl-th2 citations
6. 06*

   Charged lepton flavor violation in extended BLMSSM

   Xing-Xing Dong🇨🇳 · Shu-Min Zhao🇨🇳 · Hai-Bin Zhang🇨🇳 · Tai-Fu Feng🇨🇳

   Within the extended BLMSSM, the exotic Higgs superfields $({\Phi }_{NL},{\phi }_{NL})$ are added to make the exotic leptons heavy, and the superfields ($Y$,$Y^{\prime }$) are also introduced to make exotic leptons unstable. This new model is named as the EBLMSSM. We study some charged lepton flavor violating (CLFV) processes in detail in the EBLMSSM, including $l_j\to l_i\gamma$, muon conversion to electron in nuclei, the $\tau$ decays and $h^0\to l_i{l}_j$. Being different from BLMSSM, some particles are redefined in this new model, such as slepton, sneutrino, exotic lepton (neutrino), exotic slepton (sneutrino) and lepton neutralino. We also introduce the mass matrices of superfields $Y$ and spinor $\tilde{Y}$ in the EBLMSSM. All of these lead to new contributions to the CLFV processes. In the suitable parameter space, we obtain the reasonable numerical results. The results of this work will encourage physicists to explore new physics beyond the SM.

   hep-phEPJC(2019)·4 citations
7. 07*

   Long-term dynamics of cosmological axion strings

   Masahiro Kawasaki🇯🇵 · Toyokazu Sekiguchi🇯🇵 · Masahide Yamaguchi🇯🇵 · Jun'ichi Yokoyama🇯🇵

   We present results of new field-theoretic simulation of cosmological axion strings, which are eight times longer than previous ones. We have upgraded our simulation of physical strings in Hiramatsu et al. (2011) in terms of the number of grids as well as the suite of analysis methods. These improvements enable us to monitor a variety of quantities characterizing the dynamics of the physical string network for the longest term ever. Our extended simulations have revealed that global strings do not evolve according to the scaling solution but its scaling parameter, or the number of long strings per horizon, increases logarithmically in time. In addition, we have also found that the scaling parameter shows nontrivial dependence on the breaking scale of the Peccei-Quinn symmetry.

   hep-phastro-ph.COgr-qchep-thPTEP(2018)·113 citations
8. 08*

   Digging for Top Squarks from Higgs data: from signal strengths to differential distributions

   Andrea Banfi🇬🇧 · Andrew Bond🇬🇧 · Adam Martin🇺🇸 · Veronica Sanz🇬🇧

   One way to hunt for top squarks is to look for deviations from the Standard Model in loop level processes involving Higgses. This method is indirect, but complementary to direct searches as it does not rely on specific top squark decays. Studying inclusive Higgs production $pp\to h$ alone is insufficient, since there are parameter regions where the effects of the two top squarks approximately cancel. This degeneracy can be broken by looking at the rate for highly boosted Higgses recoiling against a jet, $pp\to h+\text{jet}$. In this paper we perform a detailed study of the complementarity of the inclusive and highly boosted processes at the LHC, both in existing Run 1 and Run 2 data, and looking forward to high luminosity. To break the degeneracy, our calculation must maintain the full mass dependence in the loop functions and therefore cannot be recast in an effective field theory framework. We quantify the dependence of both topologies in the top squark parameter space, and outline which levels of experimental and theoretical understanding would be needed for boosted Higgses to be competitive with inclusive Higgs production.

   hep-phhep-exJHEP(2018)·17 citations
9. 09*

   Inverting the mass hierarchy of jet quenching effects with prompt $b$-jet substructure

   Ivan Vitev🇺🇸

   In these proceedings, we discuss the role of heavy quark mass on the formation of parton showers. Mass effects are not well understood when parton branching occurs in nuclear matter, such as the quark-gluon plasma. Recently, a theoretically consistent picture of open heavy flavor production in ultra relativistic nuclear collisions has begun to emerge based on effective theories of QCD, such as soft collinear effective theory with Glauber gluons. We show that implementation of in-medium splitting processes containing heavy quarks into next-to-leading order calculations of heavy flavor production leads to larger cross section suppression when compared to traditional energy loss phenomenology. To better constrain the important mass dependence of in-medium splitting functions, we propose a new measurement in relativistic heavy ion collisions, based on a two-prong structure inside a reconstructed heavy flavor jet. In the region of jet transverse momenta where parton mass effects are leading, we predict a unique reversal of the mass hierarchy of jet quenching effects in heavy ion relative to proton collisions. We find that the momentum sharing distribution of prompt $b$-tagged jets is more strongly modified in comparison to the one for light jets. The work summarized here opens new directions of research on the substructure of heavy flavor jets.

   hep-phnucl-thJ.Phys.Conf.Ser.(2018)·0 citations
10. 10*

    Consistency of a gauged two-Higgs-doublet model: Scalar sector

    Abdesslam Arhrib🇲🇦 · Wei-Chih Huang🇩🇰 · Raymundo Ramos🇹🇼 · Yue-Lin Sming Tsai🇹🇼 · Tzu-Chiang Yuan🇹🇼

    We study the theoretical and phenomenological constraints imposed on the scalar sector of the gauged two Higgs doublet model proposed recently as a variant of the popular inert Higgs doublet model of dark matter. The requirements of tree-level vacuum stability and perturbative unitarity in the scalar sector are analyzed in detail. Furthermore, taking into account the constraints from the 125 GeV Higgs boson measurements at the Large Hadron Collider, we map out the allowed ranges for the fundamental parameters of the scalar potential in the model.

    hep-phPRD(2018)·18 citations
11. 11*

    Semiclassical computation of quantum effects in multiparticle production at large lambda n

    Valentin V. Khoze🇬🇧

    We use the semiclassical formalism based on singular solutions in complex time to compute scattering rates for multiparticle production at high energies. In a weakly coupled $\lambda {\varphi }^4$ scalar field theory in four dimensions, we consider scattering processes where the number of particles $n$ in the final state approaches its maximal value $n\to E/m\gg 1$, where $m$ is the particle mass. Quantum corrections to the known tree-level amplitudes in this regime are characterised by the parameter $\lambda n$ and we show that they become large at sufficiently high multiplicities. We compute full amplitudes in the large $\lambda n$ limit on multiparticle mass thresholds using the thin-wall realisation of the singular solutions in the WKB approach. We show that the scalar theory with spontaneous symmetry breaking, used here as a simplified model for the Higgs sector, leads to exponentially growing multi-particle rates within our regime which is likely to realise the high-energy Higgsplosion phenomenon. We also comment on realisation of Higgsplosion in dimensions lower than four.

    hep-phhep-th12 citations
12. 12*

    Radiative and $\rho$ transitions between heavy quarkonium and isovector four-quark states

    M.B. Voloshin🇺🇸

    The recent observation and measurement of the decay $Z_c(3900)\to \rho {\eta }_c$ provides the data on the relative strength of the pion and $\rho$ coupling in the corresponding transitions between exotic resonances and pure heavy quarkonium. It is argued that using these data, the heavy quark limit for the $c$ and $b$ quarks, the heavy quark spin symmetry (HQSS) and the vector dominance for photon emission by the light quarks, one can (approximately) quantitatively estimate the rates of the radiative transitions from ${\rm Y}(5S)$ to the expected $G$-odd states of molecular bottomonium $W_{bJ}$. The estimate of the cross section of the processes $e^{+}{e}^{-}\to \gamma W_{bJ}$ at the maximum of the ${\rm Y}(5S)$ resonance comes out in the ballpark of 0.1\,pb, which sets a benchmark for a possible search for these processes at BelleII.

    hep-phhep-exPRD(2018)·15 citations
13. 13*

    Hidden Higgs Portal Vector Dark Matter for the Galactic Center Gamma-Ray Excess from the Two-Step Cascade Annihilation, and Muon g-2

    Kwei-Chou Yang🇹🇼

    We have built a lepton-specific next-to-minimal two-Higgs-doublet-portal vector dark matter model. The vector dark matter in the hidden sector does not directly couple to the visible sector, but instead annihilates into the hidden Higgs bosons which decay through a small coupling into the CP-odd Higgs bosons. In this model, the Galactic center gamma-ray excess is mainly due to the 2-step cascade annihilation with $\tau$'s in the final state. The obtained mass of the CP-odd Higgs $A$ in the Galactic center excess fit can explain the muon $g-2$ anomaly at the 2$\sigma$ level without violating the stringent constraints from the lepton universality and $\tau$ decays. We show three different freeze-out types of the dark matter relic, called (i) the conventional WIMP dark matter, (ii) the unconventional WIMP dark matter and (iii) the cannibally co-decaying dark matter, depending on the magnitudes of the mixing angles between the hidden Higgs and visible two-Higgs doublets. The dark matter in the hidden sector is secluded from detections in the direct searches or colliders, while the dark matter annihilation signals are not suppressed in a general hidden sector dark matter model. We discuss the constraints from observations of the dwarf spheroidal galaxies and the Fermi-LAT projected sensitivity.

    hep-phastro-ph.COastro-ph.GAastro-ph.HE+1JHEP(2018)·14 citations
14. 14*

    Neutral Hadrons Disappearing into the Darkness

    D. Barducci🇮🇹 · M. Fabbrichesi🇮🇹 · E. Gabrielli🇮🇹

    We study the invisible decay of neutral hadrons in a representative model of the dark sector. The mesons $K_L$ and $B^0$ decay into the dark sector with branching rates that can be at the current experimental limits. The neutron decays with a rate that could either explain the neutron lifetime puzzle (although only for an extreme choice of the parameters and a fine tuned value of the masses) or be just above the current limit of its invisible decay (${\tau }_N^{\mathrm{inv}}\ge 10^{29}$ years) if kinematically allowed. These invisible decays of ordinary matter provide a novel and promising window into new physics that should be vigorously pursued.

    hep-phhep-exPRD(2018)·64 citations
15. 15*

    Scalar leptoquarks from GUT to accommodate the $B$-physics anomalies

    Damir Bečirević🇫🇷 · Ilja Doršner🇭🇷 · Svjetlana Fajfer🇸🇮 · Nejc Košnik🇸🇮 · Darius A. Faroughy🇸🇮 · Olcyr Sumensari🇮🇹

    We address the $B$-physics anomalies within a two scalar leptoquark model. The low-energy flavor structure of our set-up originates from two $SU(5)$ operators that relate Yukawa couplings of the two leptoquarks. The proposed scenario has a UV completion, can accommodate all measured lepton flavor universality ratios in $B$-meson decays, is consistent with related flavor observables, and is compatible with direct searches at the LHC. We provide prospects for future discoveries of the two light leptoquarks at the LHC and predict several yet-to-be-measured flavor observables.

    hep-phPRD(2018)·248 citations
16. 16*

    Reconstructing the Inflationary Landscape with Cosmological Data

    Xingang Chen🇺🇸 · Gonzalo A. Palma🇨🇱 · Bruno Scheihing Hitschfeld🇨🇱 · Spyros Sypsas🇨🇱

    We show that the shape of the inflationary landscape potential may be constrained by analyzing cosmological data. The quantum fluctuations of fields orthogonal to the inflationary trajectory may have probed the structure of the local landscape potential, inducing non-Gaussianity (NG) in the primordial distribution of the curvature perturbations responsible for the cosmic microwave background (CMB) anisotropies and our Universe's large-scale structure. The resulting type of NG (tomographic NG) is determined by the shape of the landscape potential, and it cannot be fully characterized by 3- or 4-point correlation functions. Here we deduce an expression for the profile of this probability distribution function in terms of the landscape potential, and we show how this can be inverted in order to reconstruct the potential with the help of CMB observations. While current observations do not allow us to infer a significant level of tomographic NG, future surveys may improve the possibility of constraining this class of primordial signatures.

    ↳ astro-ph.COhep-phhep-thPRL(2018)·47 citations
17. 17*

    Statistical Significance of CP Violation in Long Baseline Neutrino Experiments

    Walter Toki🇺🇸 · Thomas W. Campbell🇺🇸 · Erez Reinherz-Aronis🇺🇸

    The p-value or statistical significance of a CP conservation null hypothesis test is determined from counting electron neutrino and antineutrino appearance oscillation events. The statistical estimates include cases with background events and different data sample sizes, graphical plots to interpret results and methods to combine p-values from different experiments. These estimates are useful for optimizing the search for CP violation with different amounts of neutrino and antineutrino beam running, comparing results from different experiments and for simple cross checks of more elaborate statistical estimates that use likelihood fitting of neutrino parameters.

    ↳ hep-exhep-phphysics.data-anNucl.Instrum.Meth.A(2019)·0 citations
18. 18*

    Sensitivity of primordial black hole abundance on the reheating phase

    Rong-Gen Cai🇨🇳 · Tong-Bo Liu🇨🇳 · Shao-Jiang Wang🇨🇳

    We investigate the sensitivity of reheating history on the abundance of primordial black holes (PBHs). Contrary to the monochromatic case of mass fraction of PBH, reheating era with different e-folding and equation-of-state can have a substantial impact on the abundance of PBH with an extended mass fraction. We demonstrate explicitly this reheating sensitivity in an illustrative model of single field inflation with a quasi-inflection point, and find that both the peak position and amplitude of the extended mass fraction as well as the abundance of PBH in DM can vary by many orders of magnitude, which adds another layer of uncertainty on the PBH scenarios as dark matter.

    ↳ astro-ph.COgr-qchep-phPRD(2018)·21 citations
19. 19*

    Study of methods of resolved top quark reconstruction in semileptonic $t\bar{t}$ decay

    Jiří Kvita

    Study of methods of resolved top quarks kinematic reconstruction in the $t\bar{t}\to \ell +$jets channel is presented at the particle level as well as the fast-simulation detector level. Previous and current pseudo-top quark reconstruction algorithms are compared with suggestions presented on how to improve the reconstructed top-quark mass line shape, including the check of performance on physics observables in terms of correlations between detector, particle and parton levels, and in unfolding, with implications for current high energy physics experiments.

    ↳ hep-exhep-phNucl.Instrum.Meth.A(2018)·12 citations
20. 20*

    Non-Gaussianity from Axion-Gauge Fields Interactions during Inflation

    Emanuela Dimastrogiovanni🇺🇸 · Matteo Fasiello🇬🇧 · Robert J. Hardwick🇬🇧 · Hooshyar Assadullahi🇬🇧 · Kazuya Koyama🇬🇧 · David Wands🇬🇧

    We study the scalar-tensor-tensor non-Gaussian signal in an inflationary model comprising also an axion coupled with SU(2) gauge fields. In this set-up, metric fluctuations are sourced by the gauge fields already at the linear level providing an enhanced chiral gravitational waves spectrum. The same mechanism is at work in generating an amplitude for the three-point function that is parametrically larger than in standard single-field inflation.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2018)·69 citations
21. 21*

    Natural Inflation with a periodic non-minimal coupling

    Ricardo Z.Ferreira🇪🇸 · Alessio Notari🇪🇸 · Guillem Simeon🇪🇸

    Natural inflation is an attractive model for primordial inflation, since the potential for the inflaton is of the pseudo Nambu-Goldstone form, $V(\varphi )={\Lambda }^4[1+\cos (\varphi /f)]$, and so is protected against radiative corrections. Successful inflation can be achieved if $f\gtrsim \mathrm{few}{M}_P$ and $\Lambda \sim m_{GUT}$ where $\Lambda$ can be seen as the strong coupling scale of a given non-abelian gauge group. However, the latest observational constraints put natural inflation in some tension with data. We show here that a non-minimal coupling to gravity ${\gamma }^2(\varphi )R$, that respects the symmetry $\varphi \to \varphi +2\pi f$ and has a simple form, proportional to the potential, can improve the agreement with cosmological data. Moreover, in certain cases, satisfactory agreement with the Planck 2018 TT, TE, EE and low P data can be achieved even for a periodicity scale of approximately $M_p$.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2018)·41 citations
22. 22*

    Probing the in-Medium QCD Force by Open Heavy-Flavor Observables

    Shuai Y.F. Liu🇺🇸 · Min He🇨🇳 · Ralf Rapp🇺🇸

    The determination of the color force in a quark-gluon plasma (QGP) is a key objective in the investigation of strong-interaction matter. Open and hidden heavy-flavor observables in heavy-ion collisions (HICs) are believed to provide insights into this problem by comparing calculations of heavy-quark (HQ) and quarkonium transport with pertinent experimental data. In this work, we utilize the $T$-matrix formalism to compute charm-quark transport coefficients for various input potentials previously extracted from simultaneous fits to lattice-QCD data for HQ free energies, quarkonium correlators and the QGP equation of state. We investigate the impact of off-shell effects (spectral functions) in the QGP medium on the HQ transport, and compare to earlier results using the free or internal HQ energies as potential proxies. We then employ the transport coefficients in relativistic Langevin simulations for HICs to test the sensitivity of heavy-flavor observables to the HQ interactions in the QGP. We find that a strongly-coupled $T$-matrix solution generates a HQ elliptic flow comparable to the results from the internal energy at low momentum, driven by a long-range remnant of the confining force, while falling off stronger with increasing 3-momentum. The weakly coupled $T$-matrix solution, whose underlying potential is close to the free energy, leads to an elliptic flow well below the experimentally observed range.

    ↳ nucl-thhep-phnucl-exPRC(2019)·42 citations
23. 23*

    Constructing multi-loop scattering amplitudes with manifest singularity structure

    Robert M. Schabinger🇺🇸

    The infrared exponentiation properties of dimensionally-regularized multi-loop scattering amplitudes are typically hidden at the level of the integrand, materializing only after integral evaluation. We address this long-standing problem by introducing an appropriate integral basis which is simultaneously finite and uniform weight. As an example, we cast the integrand for the QCD corrections to the two-loop massless quark electromagnetic form factor into a form where it is manifest that the ${ϵ}^{-4}$ and ${ϵ}^{-3}$ pole terms arise from the $ϵ$ expansion of the square of our one-loop master integral.

    ↳ hep-thhep-phPRD(2019)·17 citations
24. 24*

    Observable Chiral Gravitational Waves from Inflation in String Theory

    Evan McDonough🇺🇸 · Stephon Alexander🇺🇸

    We consider gravitational wave production during inflation in type IIB string theory, and the possibility of observable gravitational waves in small field inflation. We show that the gauge field excitations on a set of coincident D7 branes, itself critical for moduli stabilization and hence intrinsic to inflation in string theory, coupled with axion fields from bulk fluxes, can act as a spectator sector during inflation. This results in a large production of chiral gravitational waves, even for relatively small values of the axion-gauge field coupling. We extend this to include a monodromy for the axion, and demonstrate that in both cases an observable level of gravitational waves is produced in small field inflation in string theory, with a spectrum that is maximally chiral. Finally, we demonstrate the consistency with moduli stabilization and with arbitrary (large or small field) inflationary dynamics of the host model, considering as an explicit example Kahler Moduli Inflation.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2018)·48 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.