Tue·Nov 27, 2018Tuesday·November 27, 2018

1. 01*

   Quarkonium inside Quark-Gluon Plasma: Diffusion, Dissociation, Recombination and Energy Loss

   Xiaojun Yao🇺🇸 · Berndt Müller🇺🇸

   We consider the quarkonium diffusion, dissociation and recombination inside quark-gluon plasma. We compute scattering amplitudes in potential nonrelativistic QCD for relevant processes. These processes include the gluon absorption/emission at the order $gr$, inelastic scattering at the order $g^{2}r$ and elastic scattering with medium constituents at the order $g^2{r}^2$. We show these amplitudes satisfy the Ward identity. We also consider one-loop corrections. The dipole interaction between the color singlet and octet is not running at the one-loop level. Interference between the tree-level gluon absorption/emission and its thermal loop corrections cancels the collinear divergence in the $t$-channel inelastic scattering. The inelastic scattering has no soft divergence because of the finite binding energy of quarkonium. We write out the diffusion, dissociation and recombination terms explicitly for a Boltzmann transport equation and define the dissociation and recombination rates. Furthermore, we calculate the diffusion coefficient of quarkonium. We find our result of diffusion coefficient differs from a previous calculation by two to three orders of magnitude. We explain this and can reproduce the previous result in a certain limit. Finally we discuss two mechanisms of quarkonium energy loss inside quark-gluon plasma.

   hep-phnucl-thPRD(2019)·81 citations
2. 02*

   $U(1{)}_{\chi }$ and Seesaw Dirac Neutrinos

   Ernest Ma (UC Riverside)🇺🇸

   In the context of $SO(10)\to SU(5)\times U(1{)}_{\chi }$, it is shown how seesaw Dirac neutrinos may be obtained. In this framework, $U(1)$ lepton number is conserved, with which self-interaction dark matter with a light scalar dilepton mediator may be implemented. In addition, $U(1)$ baryon number may be broken to $(-1{)}^{3B}$, thereby generating a baryon asymmetry of the Universe. The axionic solution to the strong $CP$ problem may also be incorporated.

   hep-phLHEP(2019)·13 citations
3. 03*

   Neutrino masses and lepton mixing from $A_5\times \mathrm{CP}$

   Andrea Di Iura🇮🇹 · M.L. López-Ibáñez🇮🇹 · Davide Meloni🇮🇹

   We analyse in detail the phenomenological implications for lepton masses and mixing derived by the breaking of the discrete symmetries $A_5\times CP$ into the subgroups $Z_2\times CP$ in the neutrino sector and $Z_5$ in the charged lepton sector. We derive accurate analytic expressions for the sum of the neutrino masses ${\Sigma }_i{m}_i$ as well as for the effective Majorana masses $m_{\beta }$ and $m_{\beta \beta }$ under different hypotheses for the flavon vevs and compare them with the exact numerical results obtained from the diagonalization of the neutrino mass matrix.

   hep-phNPB(2019)·16 citations
4. 04*

   Testing the inert Zee model using lepton flavor observables

   Robinson Longas🇨🇴

   The inert Zee model is an extension of the Zee model for neutrino masses to allow for a solution to the dark matter problem that involves two vector-like fields, a doublet and a singlet of $\mathrm{SU}(2{)}_{\mathrm{L}}$, and two scalars, also a doublet and a singlet of $\mathrm{SU}(2{)}_{\mathrm{L}}$, all of them being odd under an exact ${\mathrm{Z}}_2$ symmetry. The introduction of the ${\mathrm{Z}}_2$ guarantees one-loop neutrino masses, forbids tree-level Higgs-mediated flavor changing neutral currents and ensures the stability of the dark matter candidate. Due to the natural breaking of lepton numbers in the inert Zee model, we study the phenomenology of the processes leading to these kind of signals and establish which are the most promising experimental perspectives on that matter.

   hep-ph0 citations
5. 05*

   Parallel Adaptive Monte Carlo Integration with the Event Generator WHIZARD

   Simon Braß🇩🇪 · Wolfgang Kilian🇩🇪 · Jürgen Reuter🇩🇪

   We describe a new parallel approach to the evaluation of phase space for Monte-Carlo event generation, implemented within the framework of the WHIZARD package. The program realizes a twofold self-adaptive multi-channel parameterization of phase space and makes use of the standard OpenMP and MPI protocols for parallelization. The modern MPI3 feature of asynchronous communication is an essential ingredient of the computing model. Parallel numerical evaluation applies both to phase-space integration and to event generation, thus covering the most computing-intensive parts of physics simulation for a realistic collider environment.

   hep-phhep-exphysics.comp-phEPJC(2019)·34 citations
6. 06*

   Electroweak Baryogenesis From Dark CP Violation

   Marcela Carena🇺🇸 · Mariano Quirós🇪🇸 · Yue Zhang🇺🇸

   We present a novel mechanism of electroweak baryogenesis where \textit{CP} violation occurs in a dark sector, comprised of standard model gauge singlets, thereby evading the strong electric dipole moment constraints. In this framework, the background of time-like component of a new gauge boson $Z_{\mu }^{\prime }$, generated at electroweak temperatures, drives the electroweak sphaleron processes to create the required baryon asymmetry. We first discuss the crucial ingredients for this mechanism to work, and then show that all of them can be elegantly embedded in ultraviolet completions with spontaneously broken gauged lepton number. The models under consideration have a rich phenomenology and can be experimentally probed in leptophilic $Z^{\prime }$ searches, dark matter searches, heavy Majorana neutrino searches, as well as through hunting for new Higgs portal scalars in multi-lepton channels at colliders.

   hep-phastro-ph.COhep-exPRL(2019)·51 citations
7. 07*

   New Insights on Low Energy $\pi N$ Scattering Amplitudes: Comprehensive Analyses at $\mathcal{O}(p^3)$ Level

   Yu-Fei Wang🇨🇳 · De-Liang Yao🇪🇸 · Han-Qing Zheng🇨🇳

   A production representation of partial-wave $S$ matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the $\mathcal{O}(p^3)$ results obtained in covariant baryon chiral perturbation theory within the extended-on-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in $S_{11}$ and $P_{11}$ channels, as conjectured in our previous paper~\citep{Wang:2017agd}, are firmly established. Specifically, the pole mass of the $S_{11}$ hidden resonance is determined to be $(895\pm 81)-(164\pm 23)i$ MeV, whereas, the virtual pole in the $P_{11}$ channel locates at $(966\pm 18)$ MeV. It is found that analyses at the $\mathcal{O}(p^3)$ level improves significantly the fit quality, comparing with the previous $\mathcal{O}(p^2)$ one. Quantitative studies with cautious physical discussions are also conducted for the other $S$- and $P$-wave channels.

   hep-phnucl-thCPC(2019)·18 citations
8. 08*

   Sum rules and the DGLAP evolution in presence of $U(1{)}_B$ anomaly

   Thitipat Sainapha🇹🇭

   The possibility to modify both quarks sum rules and the DGLAP evolution equation are investigated. In presence of anomalous baryon global symmetry, the quark sum rules are no longer the same as usual. In addition, the DGLAP equation is also changed to be self-consistent with modified sum rules. This way of modification turns out to satisfy the Sakharov's baryogenesis requirements. We also assume the existence of the factorization theorem in relevant scale to maintain the naive parton model. Consequently, if this is presumably going to be true, there might be a new powerful constraint for constructing the beyond standard model physics.

   hep-ph0 citations
9. 09*

   Electroweak Phase Transition, Gravitational Waves and Dark Matter in Two Scalar Singlet Extension of The Standard Model

   Vahid Reza Shajiee🇮🇷 · Ali Tofighi🇮🇷

   In this paper, the electroweak phase transition, the gravitational waves and the dark matter issues are investigated in two scalar singlet extension of the standard model. The detectability of the gravitational wave signals are discussed by comparing the results with the sensitivity curves of $\mathbf{eLISA}$, $\mathbf{ALIA}$, $\mathbf{DECIGO}$ and $\mathbf{BBO}$ detectors. It is shown that the results support the recent reports on the dark matter relic density by $\mathbf{Planck}$ $2018$ collaboration and the direct detection experiment by $XENON1T$ $2018$ collaboration.

   hep-phastro-ph.COEPJC(2019)·42 citations
10. 10*

    Comparing a few distributions of transverse momenta in high energy collisions

    Qi Wang🇨🇳 · Pei-Pin Yang🇨🇳 · Fu-Hu Liu🇨🇳

    Transverse momentum spectra of particles produced in high energy collisions are very important due to their relations to the excitation degree of interacting system. To describe the transverse momentum spectra, one can use more than one probability density functions of transverse momenta, which are simply called the functions or distributions of transverse momenta in some cases. In this paper, a few distributions of transverse momenta in high energy collisions are compared with each other in terms of plots to show some quantitative differences. Meanwhile, in the framework of Tsallis statistics, the distributions of momentum components, transverse momenta, rapidities, and pasudorapidities are obtained according to the analytical and Monte Carlo methods. These analyses are useful to understand carefully different distributions in high energy collisions.

    hep-phhep-exnucl-exnucl-thResults Phys.(2019)·6 citations
11. 11*

    Neutrinoless Double Beta Decay and Light Sterile Neutrino

    C. H. Jang🇰🇷 · B. J. Kim🇰🇷 · Y. J. Ko🇰🇷 · K. Siyeon🇰🇷

    Recent neutrino experiment results show a preference for the normal neutrino mass ordering. The global efforts to search for neutrinoless double beta decays undergo a broad gap with the approach to the prediction in the three-neutrino framework based on the normal ordering. This research is intended to show that it is possible to find a neutrinoless double beta decay signal even with normal ordered neutrino masses. We propose the existence of a light sterile neutrino as a solution to the higher effective mass of the electron neutrino expected by the current experiments. A few short-baseline oscillation experiments gave rise to a limit on the mass of the sterile neutrino and its mixing with the lightest neutrino. We demonstrate that the results of neutrinoless double beta decays can also narrow down the range of the mass and the mixing angle of the light sterile neutrino.

    hep-phhep-exJ.Korean Phys.Soc.(2018)·4 citations
12. 12*

    Study of semileptonic decays $B\to \pi l^{+}{l}^{-}$ and $B\to \rho l^{+}{l}^{-}$ in non-universal Z' model

    P. Nayek🇮🇳 · P. Maji🇮🇳 · S. Sahoo🇮🇳

    Semileptonic B meson decays induced by $b\to s(d)l^{+}{l}^{-}$ flavour changing neutral current (FCNC) transitions are very important to probe the quark-flavour sector of the standard model (SM) and also offer a probe to test new physics (NP). Although there exists a lot of precise results on $b\to s{l}^{+}{l}^{-}$ induced processes, there is lack of sufficient data for $b\to d{l}^{+}{l}^{-}$ induced decays. Here, we are interested to study $B\to \pi l^{+}{l}^{-}$ and $B\to \rho l^{+}{l}^{-}$ decays which proceed via $b\to d{l}^{+}{l}^{-}$ transition at the quark level. In this work, we investigate the differential branching ratio, forward-backward asymmetry, CP violation asymmetry and lepton polarization asymmetry in these two decay channels in a non-universal Z' model. We find a significant deviation from the SM value of these physical observables for these decays which provide a clear conjecture for NP arising from Z' gauge boson.

    hep-phPRD(2019)·12 citations
13. 13*

    New algorithm to study the pseudo-Wigner solution of the quark gap equation in the framework of the (2+1)-flavor NJL model

    Cheng-Ming Li🇨🇳 · Pei-Lin Yin🇨🇳 · Hong-Shi Zong🇨🇳

    In this paper, we study the pseudo-Wigner solution of the quark gap equation with a recently proposed algorithm in the framework of the (2+1)-flavor Nambu-Jona-Lasinio (NJL) model. We find that for the current quark mass $m_{\mathrm{u},\mathrm{d}}=5.5$ MeV and chemical potential $\mu <{\mu }_{\mathrm{TCP}}=272.5$ MeV, the Nambu solution and the positive pseudo-Wigner solution obtained via this algorithm is consistent with the physical solution obtained with the iterative method. Furthermore, the algorithm we used can help to illustrate the evolution of the solutions of the gap equation from the chiral limit to non-chiral limit and gives a prediction where the crossover line is located in the phase diagram for $\mu <272.5$ MeV. In addition, we also study the chiral susceptibilities as well as the loss of solutions for different chemical potentials.

    hep-phPRD(2019)·14 citations
14. 14*

    Contributions of unstable and virtual particles to nuclear form factors

    M. L. Nekrasov🇷🇺

    The coherent meson scattering off heavy nuclei with the production of two particles in the final state is investigated. We obtain the form factors for the direct production of the final state and through intermediate particles, unstable ones that can decay inside the nucleus and virtual ones. The cases of scattering both in the Coulomb and in the strong field of the nucleus are considered. This work is stimulated by an experimental study of the chiral anomaly in a beam of charged kaons in the OKA facility.

    hep-phEPJA(2019)·0 citations
15. 15*

    Tau-decay determination of the strong coupling

    Antonio Pich🇪🇸

    We review the current status of the determination of the strong coupling from tau decay. Using the most recent release of the ALEPH data, a very comprehensive phenomenological analysis has been performed, exploring all strategies previously considered in the literature and several complementary approaches. Once their actual uncertainties are properly assessed, the results from all adopted methodologies are in excellent agreement, leading to a very robust and reliable value of the strong coupling, ${\alpha }_s^{(n_f=3)}(m_{\tau }^2)=0.328\pm 0.013$, which implies ${\alpha }_s^{(n_f=5)}(M_Z^2)=0.1197\pm 0.0015$.

    hep-phhep-exSciPost Phys.Proc.(2019)·8 citations
16. 16*

    Spin-isospin correlated configurations in complex nuclei and neutron skin effect in W${}^{\pm }$ production in high-energy proton-lead collisions

    Massimiliano Alvioli🇮🇹 · Mark Strikman🇺🇸

    We extend our Monte Carlo generator of global configurations in nuclei to include different spatial distributions of protons and neutrons in heavy nuclei taking into account the difference of spatial correlations between two protons, two neutrons and proton-neutron pairs. These configurations are used for building an event generator for proton-heavy nucleus collisions at the LHC for final states with a hard interaction in the channels where cross section for p-p and p-n scattering differ. Soft interactions are taken into account in the color fluctuation extension of the Glauber algorithm taking into account the inherently different transverse geometry of soft and hard p-N collisions. We use the new event generator to test an interesting observation of Physics Letters B745 (2015) 73-78, that the ratio of W${}^{+}$/W${}^{-}$ production rates in p-Pb collisions should significantly deviate from the inclusive value for peripheral collisions due to the presence of a neutron skin. We qualitatively confirm expectation of Physics Letters B745 (2015) 73-78, though for a realistic centrality trigger, we find the effect to be a factor of two smaller than the original estimate.

    hep-phhep-exnucl-thPRC(2019)·21 citations
17. 17*

    Note on invisible decays of light mesons

    Dao-Neng Gao🇨🇳

    A search for the invisible decays of $\omega$ and $\varphi$ mesons in $J/\psi \to \omega (\varphi )\eta$ transitions has been performed by the BESIII Collaboration very recently. Inspired by this experimental study, we compute the lowest order contribution to branching ratios of $\mathcal{B}(V\to \bar{\nu }\nu )$ with $V$ denoting $\rho ,\omega ,\varphi$, as the standard model background to these invisible decays. Our predictions are far below the upper bounds given by the BESIII experiment. We also analyze the $J/\psi \to \eta ({\eta }^{\prime })\bar{\nu }\nu$ processes, and estimate their decay rates. Furthermore, the invisible decays of light pseudoscalar mesons $P$ including ${\pi }^0$, $\eta$, and ${\eta }^{\prime }$ are reexamined in the present note. It is shown that, due to the helicity suppression of the two-neutrino final state, the standard model contributions to $P\to \mathrm{invisible}$ decays are dominated by $P\to \bar{\nu }\nu \bar{\nu }\nu$ processes.

    hep-phhep-exPRD(2018)·16 citations
18. 18*

    The ${\bar{D}}^{\ast }{\bar{D}}^{\ast }{\Sigma }_c$ Three-Body System

    Manuel Pavon Valderrama🇨🇳

    In the molecular picture the hidden-charm, pentaquark-like $P_c(4450)$ resonance is a ${\bar{D}}^{\ast }{\Sigma }_c$ bound state with quantum numbers $I=\frac{1}{2}$ and $J^P={\frac{3}{2}}^{-}$. If this happens to be the case, it will be natural to expect the existence of ${\bar{D}}^{\ast }{\bar{D}}^{\ast }{\Sigma }_c$ three-body bound states. The most probable quantum numbers for a bound ${\bar{D}}^{\ast }{\bar{D}}^{\ast }{\Sigma }_c$ trimer are the isoscalar $J^P={\frac{1}{2}}^{+}$, ${\frac{5}{2}}^{+}$ and the isovector $J^P={\frac{3}{2}}^{+}$, ${\frac{5}{2}}^{+}$ configurations. Calculations within a contact-range theory indicate a trimer binding energy $B_3\sim 3-5\mathrm{MeV}$ and $14-16\mathrm{MeV}$ for the isoscalar ${\frac{1}{2}}^{+}$ and ${\frac{5}{2}}^{+}$ states and $B_3\sim 1-3\mathrm{MeV}$ and $3-5\mathrm{MeV}$ for the isovector ${\frac{3}{2}}^{+}$ and ${\frac{5}{2}}^{+}$ states, respectively, with $B_3$ relative to the ${\bar{D}}^{\ast }{P}_c(4450)$ threshold. These predictions are affected by a series of error sources that we discuss in detail.

    hep-phhep-exhep-latnucl-thPRD(2019)·5 citations
19. 19*

    The next-to-leading order corrections to rho meson electromagnetic form factors in the $k_T$ factorization approach

    Ya-lan Zhang🇨🇳 · Jun Hua🇨🇳 · Dong-Sheng Li🇨🇳 · Zhen-Jun Xiao🇨🇳

    In this paper we calculate the next-to-leading-order (NLO) corrections to $\rho$-meson electromagnetic form factors by employing the $k_T$ factorization approach. We find that the NLO correction to $F_i(Q^2)(i=LT,TL)$ is around $30\%$ of the leading-order (LO) contributionin the region $Q^2>2Ge{V}^2$. The NLO correction to $F_{LL}(Q^2)$ is close to $20\%$ of the LO one in the region $Q^2>3Ge{V}^2$. The NLO radiative corrections to the electric, magnetic, and quadruple form factors $F_j(Q^2)(j=1,2,3)$ are sizeable in magnitude and agree with those from other approaches.

    hep-phNPB(2019)·3 citations
20. 20*

    Electron g-2 with flavor violation in MSSM

    Bhaskar Dutta🇺🇸 · Yukihiro Mimura🇯🇵

    The muon $g-2$ anomaly is a long-standing discrepancy from its standard model prediction. The recent improved measurement of the fine structure constant makes the electron $g-2$ anomaly very interesting for both sign and magnitude in comparison to the muon $g-2$ anomaly. In order to explain both muon and electron $g-2$ anomalies, we introduce flavor violation in the minimal supersymmetric standard model (MSSM) as a low energy theory. The lepton flavor violating process $\tau \to e\gamma$ is one the major constraints to explain both $g-2$ anomalies simultaneously emerging from flavor violating terms. We show various mass spectra of sleptons, neutralinos, and charginos, consistent with the LHC results, to explain both anomalies after satisfying the flavor violation constraint.

    hep-phPLB(2019)·70 citations
21. 21*

    Ultraviolet Completion of a Composite Asymmetric Dark Matter Model with a Dark Photon Portal

    Masahiro Ibe🇯🇵 · Ayuki Kamada🇰🇷 · Shin Kobayashi🇯🇵 · Takumi Kuwahara🇰🇷 · Wakutaka Nakano🇯🇵

    Composite asymmetric dark matter scenarios naturally explain why the dark matter mass density is comparable with the visible matter mass density. Such scenarios generically require some entropy transfer mechanism below the composite scale; otherwise, their late-time cosmology is incompatible with observations. A tiny kinetic mixing between a dark photon and the visible photon is a promising example of the low-energy portal. In this paper, we demonstrate that grand unifications in the dark and the visible sectors explain the origin of the tiny kinetic mixing. We particularly consider an ultraviolet completion of a simple composite asymmetric dark matter model, where asymmetric dark matter carries a $B-L$ charge. In this setup, the longevity of asymmetric dark matter is explained by the $B-L$ symmetry, while the dark matter asymmetry originates from the $B-L$ asymmetry generated by thermal leptogenesis. In our minimal setup, the Standard Model sector and the dark sector are unified into $SU(5{)}_{\mathrm{GUT}}\times SU(4{)}_{\mathrm{DGUT}}$ gauge theories, respectively. This model generates required $B-L$ portal operators while suppressing unwanted higher-dimensional operators that could wash out the generated $B-L$ asymmetry.

    hep-phJHEP(2019)·28 citations
22. 22*

    Heavy resonances and the electroweak effective theory

    Ignasi Rosell🇪🇸 · Claudius Krause🇺🇸 · Antonio Pich🇪🇸 · Joaquín Santos🇪🇸 · Juan José Sanz-Cillero🇪🇸

    Taking into account the negative results of direct searches for beyond the Standard Model fields and the consequent mass gap between Standard Model and possible unknown states, the use of electroweak effective theories is justified. Whereas at low energies we consider a non-linear realization of the electroweak symmetry breaking with a singlet Higgs and a strongly-coupled ultraviolet completion, at higher energies the known particles are assumed to be coupled to heavy states: bosonic fields with $J^P=0^{\pm }$ and $J^P=1^{\pm }$ (in electroweak triplets or singlets and in QCD octets or singlets) and fermionic states with $J=\frac{1}{2}$ (in electroweak doublets and in QCD triplets or singlets). By integrating out these heavy resonances, the pattern of next-to-leading order low-energy constants among the light fields can be studied. A phenomenological study trying to estimate the scale of these resonances is also shown.

    hep-phPoS(2019)·0 citations
23. 23*

    Inclusive dijet photoproduction in ultraperipheral heavy-ion collisions at the CERN LHC in next-to-leading order QCD

    V. Guzey (Jyvaskyla U. & Helsinki U. & St. Petersburg, INP)🇷🇺 · M. Klasen (Munster U., ITP)🇩🇪

    We compute the cross section of inclusive dijet photoproduction in ultraperipheral Pb-Pb collisions at the LHC using next-to-leading order perturbative QCD. We demonstrate that our theoretical calculations provide a good description of various kinematic distributions measured by the ATLAS collaboration. We find that the calculated dijet photoproduction cross section is sensitive to nuclear modifications of parton distribution functions (PDFs) at the level of 10 to 20%. Hence, this process can be used to reduce uncertainties in the determination of these nuclear PDFs, whose current magnitude is comparable to the size of the calculated nuclear modifications of the dijet photoproduction cross section.

    hep-phnucl-exPRC(2019)·43 citations
24. 24*

    Heavy Majorana Neutrino Production at Future $ep$ Colliders

    Shi-Yuan Li🇨🇳 · Zong-Guo Si🇨🇳 · Xing-Hua Yang🇨🇳

    The heavy singlet Majorana neutrinos are introduced to generate the neutrino mass in the so-called phenomenological type-I seesaw mechanism. The phenomena induced by the heavy Majorana neutrinos are important to search for new physics. In this paper, we explore the heavy Majorana neutrino production and decay at future $e^{-}p$ colliders. The corresponding cross sections via $W$ and photon fusion are predicted for different collider energies. Combined with the results of the heavy Majorana neutrino production via single $W$ exchange, this work can provide helpful information to search for heavy Majorana neutrinos at future $e^{-}p$ colliders.

    hep-phPLB(2019)·15 citations
25. 25*

    Study of localized $CP$ violation in $B^{-}\to {\pi }^{-}{\pi }^{+}{\pi }^{-}$ and the branching ratio of $B^{-}\to \sigma (600){\pi }^{-}$ in the QCD factorization approach

    Jing-Juan Qi · Zhen-Yang Wang · Xin-Heng Guo · Zhen-Hua Zhang

    In this work, within the QCD factorization approach, we study the localized integrated $CP$ violation in the $B^{-}\to {\pi }^{-}{\pi }^{+}{\pi }^{-}$ decay and the branching fraction of the $B^{-}\to \sigma {\pi }^{-}$ decay. Both the resonance and nonresonance contributions are included when we study the localized $CP$ asymmetry in the $B^{-}\to {\pi }^{-}{\pi }^{+}{\pi }^{-}$ decay. The resonance contributions from the scalar $\sigma (600)$ and vector ${\rho }^0(770)$ mesons are included. For the $\sigma (600)$ meson, we apply both the Breit-Wigner and Bugg models to deal with its propagator, and obtain $\mathcal{B}(B^{-}\to \sigma (600){\pi }^{-})<1.67\times 10^{-6}$ and $\mathcal{B}(B^{-}\to \sigma (600){\pi }^{-})<1.946\times 10^{-5}$ in these two models, respectively. We find that there is no allowed divergence parameters ${\rho }_S$ and ${\varphi }_S$ to satisfy the experimental data ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}({\pi }^{-}{\pi }^{+}{\pi }^{-})=0.584\pm 0.082\pm 0.027\pm 0.007$ in the region $m_{{\pi }^{+}{\pi }^{-}\mathrm{high}}^2>15$ ${\mathrm{GeV}}^2$ and $m_{{\pi }^{+}{\pi }^{-}\mathrm{low}}^2<0.4$ ${\mathrm{GeV}}^2$ and the upper limit of $\mathcal{B}(B^{-}\to \sigma (600){\pi }^{-})$ in the Breit-Wigner model, however, there exists the region ${\rho }_S\in [1.70,3.34]$ and ${\varphi }_S\in [0.50,4.50]$ satisfying the data for ${\mathcal{A}}_{\mathcal{C}\mathcal{P}}({\pi }^{-}{\pi }^{+}{\pi }^{-})$ and the upper limit of $\mathcal{B}(B^{-}\to \sigma (600){\pi }^{-})$ in the Bugg model. This reveals that the Bugg model is more plausible than the Breit-Wigner model to describe the propagator of the $\sigma (600)$ meson even though the finite width effects are considered in both models. The large values of ${\rho }_S$ indicate that the contributions from weak annihilation and hard spectator scattering processes are both large, especially, the weak annihilation contribution should not be negleted for $B$ decays to final states including a scalar meson.

    hep-phNPB(2019)·7 citations
26. 26*

    Kinematic strangeness production in cluster hadronization

    Cody B. Duncan🇦🇺 · Patrick Kirchgaeßer🇩🇪

    We present a modification to the non-perturbative strangeness production mechanisms in the Monte-Carlo event generator Herwig in order to make the processes more dynamic and collective. We compare the model to a series of observables for soft physics at both LEP and LHC.

    hep-phEPJC(2019)·23 citations
27. 27*

    The strong decay patterns of $Z_c$ and $Z_b$ states in the relativized quark model

    Guang-Juan Wang🇨🇳 · Xiao-Hai Liu🇨🇳 · Li Ma🇩🇪 · Xiang Liu🇨🇳 · Xiao-Lin Chen🇨🇳 · Wei-Zhen Deng🇨🇳 · Shi-Lin Zhu🇨🇳

    Employing the relativized quark model and the quark-interchange model, we investigate the decay of the charged heavy quarkonium-like states $Z_c(3900)$, $Z_c(4020)$, $Z_c(4430)$, $Z_b(10610)$ and $Z_b(10650)$ into the ground and radially excited heavy quarkonia via emitting a pion meson. The $Z_c$ and $Z_b$ states are assumed to be hadronic molecules composed of open-flavor heavy mesons. The calculated decay ratios can be compared with the experimental data, which are useful in judging whether the molecule state assignment for the corresponding $Z_c$ or $Z_b$ state is reasonable or not. The theoretical framework constructed in this work will be helpful in revealing the underlying structures of some exotic hadrons.

    hep-phEPJC(2019)·29 citations
28. 28*

    $Z$-boson polarization as a model-discrimination analyzer

    Seong Youl Choi🇰🇷

    Determining the spin of any new particle is critical in identifying the true theory among various extensions of the Standard Model (SM). The degree of $Z$-boson polarization in any two-body decay process $A\to BZ$ is sensitive to the spin assignments of two new particles $A$ and $B$. Considering all possible spin-0, 1/2 and 1 combinations in a renormalizable field theory, we demonstrate that $Z$-boson polarization can indeed play a role of a decisive and universal analyzer in distinguishing the different spin assignments.

    hep-phPRD(2018)·9 citations
29. 29*

    Radiative dynamical mass of planar charged fermion in a constant homogeneous magnetic field

    V. R. Khalilov🇷🇺

    The effective Lagrangian and mass operator are calculated for planar charged massive and massless fermions in a constant external homogeneous magnetic field in the one-loop approximation of the 2+1 dimensional quantum electrodynamics (QED${}_{2+1}$). We obtain the renormalizable effective Lagrangian and the fermion mass operator for a charged fermion of mass $m$ and then calculate these quantities for the massless case. The radiative corrections to the mass of charged massless fermion when it occupies the lowest Landau level are found for the cases of the pure QED${}_{2+1}$ as well as the so-called reduced QED${}_{3+1}$ on a 2-brane. The fermion masses were found can be generated dynamically by an external magnetic field in the pure QED${}_{2+1}$ if the charged fermion has small bare mass $m_0$ and in the reduced QED${}_{3+1}$ on a 2-brane even at $m_0=0$. The dynamical mass seems to be likely to be revealed in monolayer graphene in the presence of constant homogeneous magnetic field (normal to the graphene sample).

    hep-phquant-phEPJC(2019)·9 citations
30. 30*

    Projections for model-independent sensitivity estimates on top-quark anomalous electromagnetic couplings at the FCC-he

    A. A. Billur🇹🇷 · M. Köksal🇹🇷 · A. Gutiérrez-Rodríguez🇲🇽 · M. A. Hernández-Ruíz🇲🇽

    The measurement of the top-quark anomalous electromagnetic couplings is one of the most important goals of the top-quark physics program in the present and future collider experiments. This would provide direct information on the non-standard interactions of the top-quark. We study a top-quark pair production scenario at the Future Circular Collider Hadron-Electron (FCC-he) through $e^{-}p\to e^{-}{\gamma }^{\ast }{\gamma }^{\ast }p\to e^{-}t\bar{t}p$ collisions, which will provide information about sensitivities on anomalous ${\hat{a}}_V$ and ${\hat{a}}_A$ couplings at $95\%C.L.$, and the possibility of probing new physics. Energy of the $e^{-}$ beams is taken to be $E_e=250GeV$ and $500GeV$ and the energy of the $p$ beams is taken to be $E_p=50TeV$, with these energies the FCC-he may sensitivity estimates on top-quark electromagnetic dipole moments ${\hat{a}}_V$ and ${\hat{a}}_A$ of the order $\mathcal{O}(10^{-2}-10^{-1})$.

    hep-phEur.Phys.J.Plus(2019)·13 citations
31. 31*

    Resummation for rapidity distributions in top-quark pair production

    Benjamin D. Pecjak🇬🇧 · Darren J. Scott🇳🇱 · Xing Wang🇨🇳 · Li Lin Yang🇨🇳

    We extend our framework for the simultaneous resummation of soft and small-mass logarithms to rapidity distributions in top quark pair production. We give numerical results for the rapidity distribution of the top quark or the anti-top quark, as well as the rapidity distribution of the $t\bar{t}$ pair, finding that resummation effects stabilize the dependence of the differential cross sections on the choice of factorization scale. We compare our results with recent measurements at the Large Hadron Collider and find good agreement. Our results may be useful in the extraction of the gluon parton distribution function from $t\bar{t}$ production.

    hep-phhep-exJHEP(2019)·7 citations
32. 32*

    Digging for Dark Matter: Spectral Analysis and Discovery Potential of Paleo-Detectors

    Thomas D. P. Edwards🇳🇱 · Bradley J. Kavanagh🇳🇱 · Christoph Weniger🇳🇱 · Sebastian Baum🇸🇪 · Andrzej K. Drukier🇸🇪 · Katherine Freese🇸🇪 · Maciej Górski🇵🇱 · Patrick Stengel🇸🇪

    Paleo-detectors are a recently proposed method for the direct detection of Dark Matter (DM). In such detectors, one would search for the persistent damage features left by DM--nucleus interactions in ancient minerals. Initial sensitivity projections have shown that paleo-detectors could probe much of the remaining Weakly Interacting Massive Particle (WIMP) parameter space. In this paper, we improve upon the cut-and-count approach previously used to estimate the sensitivity by performing a full spectral analysis of the background- and DM-induced signal spectra. We consider two scenarios for the systematic errors on the background spectra: i) systematic errors on the normalization only, and ii) systematic errors on the shape of the backgrounds. We find that the projected sensitivity is rather robust to imperfect knowledge of the backgrounds. Finally, we study how well the parameters of the true WIMP model could be reconstructed in the hypothetical case of a WIMP discovery.

    hep-phastro-ph.COastro-ph.IMPRD(2019)·50 citations
33. 33*

    Destabilization of the EW vacuum in non-minimally coupled inflation

    Stanislav Rusak🇸🇪

    Current cosmological data favour inflationary models non-minimally coupled to gravity. In this work we study the implications of the metastability of the electroweak vacuum in this framework. We consider an inflaton field with a non-minimal coupling to Ricci curvature and a portal coupling between the Higgs field and the inflaton and find that the ratio of the two couplings is severely constrained from stability during inflation and reheating dynamics, with constraints becoming more severe for weaker non-minimal coupling as during inflation Higgs fluctuations are amplified by inflationary expansion and after inflation by parametric resonance due to an oscillating inflaton background.

    hep-phhep-thJCAP(2020)·11 citations
34. 34*

    Electroweak phase transition in the scotogenic model

    Alejandro Correa López🇨🇴

    In this work we study the behavior of the effective scalar potential at zero and finite temperature of the scotogenic model. In particular, we analyze the impact of the Yukawa couplings associated to the right--handed neutrinos on the electroweak phase transition.

    hep-ph0 citations
35. 35*

    Single spin asymmetry in forward $pA$ collisions: Phenomenology at RHIC

    Sanjin Benić🇯🇵 · Yoshitaka Hatta🇺🇸

    We confront the theoretical result of single spin asymmetry (SSA) $A_N$ in forward $pA$ collisions $p^{\uparrow }A\to hX$ including the gluon saturation effect with the recent preliminary experimental data from the PHENIX and STAR collaborations at RHIC. While we find overall reasonable agreement with the STAR data, our results indicate that the strong nuclear suppression of the asymmetry $A_N\sim A^{-1/3}$ observed by the PHENIX collaboration cannot be explained within the present understanding of this problem.

    hep-phhep-exPRD(2019)·17 citations
36. 36*

    Regularization issues for a cold and dense quark matter model in $\beta -$equilibrium

    Dyana C. Duarte🇧🇷 · Ricardo L.S. Farias🇧🇷 · Rudnei O. Ramos🇧🇷

    A regularization scheme that explicitly separates vacuum contributions from medium effects is applied to a Nambu--Jona-Lasinio model with diquark interactions and in $\beta -$equilibrium. We perform a comparison of this proposed scheme with the more traditional one, where no separation of vacuum and medium effects is done. Our results point to both qualitative and quantitative important differences between these two methods, in special regarding the phase structure of the model in the cold and dense nuclear matter case.

    hep-phhep-thnucl-thPRD(2019)·19 citations
37. 37*

    Simple A4 models for dark matter stability with texture zeros

    Leon M.G. de la Vega🇲🇽 · R. Ferro-Hernandez🇲🇽 · E. Peinado🇲🇽

    In a simple framework which naturally incorporates dark matter stability and neutrino phenomenology, we compute all the possible texture zeros which arise when the non-abelian flavor symmetry A4 is spontaneously broken to Z2. As a result, we obtain four textures with two vanishing matrix elements. Two of such textures predict a zero contribution to the neutrinoless double beta decay effective mass parameter at tree level, and as a one loop bound we get $m_{ee}<8\times 10^{-2}$ meV. These are compatible with the normal ordering for the neutrino masses and the allowed range for the lightest neutrino mass is between $m_{{\nu }_{min}}\sim 3$ meV and $m_{{\nu }_{max}}\sim 8$ meV. Additionally we obtain dark matter stability linked to the way the flavor symmetry is broken, leaving a residual Z2 symmetry

    hep-phPRD(2019)·33 citations
38. 38*

    SModelS v1.2: long-lived particles, combination of signal regions, and other novelties

    Federico Ambrogi🇦🇹 · Juhi Dutta🇮🇳 · Jan Heisig🇧🇪 · Sabine Kraml🇫🇷 · Suchita Kulkarni🇦🇹 · Ursula Laa🇦🇺 · Andre Lessa🇧🇷 · Philipp Neuhuber🇦🇹 · Humberto Reyes-González🇫🇷 · Wolfgang Waltenberger🇦🇹 · Matthias Wolf🇦🇹

    SModelS is an automatised tool enabling the fast interpretation of simplified model results from the LHC within any model of new physics respecting a ${\mathbb{Z}}_2$ symmetry. With the version 1.2 we announce several new features. First, previous versions were restricted to missing energy signatures and assumed prompt decays within each decay chain. SModelS v1.2 considers the lifetime of each ${\mathbb{Z}}_2$-odd particle and appropriately takes into account missing energy, heavy stable charge particle and R-hadron signatures. Second, the current version allows for a combination of signal regions in efficiency map results whenever a covariance matrix is available from the experiment. This is an important step towards fully exploiting the constraining power of efficiency map results. Several other improvements increase the user-friendliness, such as the use of wildcards in the selection of experimental results, and a faster database which can be given as a URL. Finally, smodelsTools provides an interactive plots maker to conveniently visualize the results of a model scan.

    hep-phComput.Phys.Commun.(2020)·98 citations
39. 39*

    First measurements of absolute branching fractions of ${\Xi }_c^0$ at Belle

    Belle Collaboration: Y. B. Li · C. P. Shen · C. Z. Yuan · I. Adachi · H. Aihara · S. Al Said · D. M. Asner · T. Aushev · R. Ayad · I. Badhrees · V. Bansal · C. Beleño and 148 other authors

    We present the first measurements of absolute branching fractions of ${\Xi }_c^0$ decays into ${\Xi }^{-}{\pi }^{+}$, $\Lambda K^{-}{\pi }^{+}$, and $p{K}^{-}{K}^{-}{\pi }^{+}$ final states. The measurements are made using a data set comprising $(772\pm 11)\times 10^6$ $B\bar{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB $e^{+}{e}^{-}$ collider. We first measure the absolute branching fraction for $B^{-}\to {\bar{\Lambda }}_c^{-}{\Xi }_c^0$ using a missing-mass technique; the result is $\mathcal{B}(B^{-}\to {\bar{\Lambda }}_c^{-}{\Xi }_c^0)=(9.51\pm 2.10\pm 0.88)\times 10^{-4}$. We subsequently measure the product branching fractions $\mathcal{B}(B^{-}\to {\bar{\Lambda }}_c^{-}{\Xi }_c^0)\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{\pi }^{+})$, $\mathcal{B}(B^{-}\to {\bar{\Lambda }}_c^{-}{\Xi }_c^0)\mathcal{B}({\Xi }_c^0\to \Lambda K^{-}{\pi }^{+})$, and $\mathcal{B}(B^{-}\to {\bar{\Lambda }}_c^{-}{\Xi }_c^0)\mathcal{B}({\Xi }_c^0\to p{K}^{-}{K}^{-}{\pi }^{+})$ with improved precision. Dividing these product branching fractions by the result for $B^{-}\to {\bar{\Lambda }}_c^{-}{\Xi }_c^0$ yields the following branching fractions: $\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{\pi }^{+})=(1.80\pm 0.50\pm 0.14)\%$, $\mathcal{B}({\Xi }_c^0\to \Lambda K^{-}{\pi }^{+})=(1.17\pm 0.37\pm 0.09)\%$, and $\mathcal{B}({\Xi }_c^0\to p{K}^{-}{K}^{-}{\pi }^{+})=(0.58\pm 0.23\pm 0.05)\%.$ For the above branching fractions, the first uncertainties are statistical and the second are systematic. Our result for $\mathcal{B}({\Xi }_c^0\to {\Xi }^{-}{\pi }^{+})$ can be combined with ${\Xi }_c^0$ branching fractions measured relative to ${\Xi }_c^0\to {\Xi }^{-}{\pi }^{+}$ to yield other absolute ${\Xi }_c^0$ branching fractions.

    ↳ hep-exhep-phPRL(2019)·76 citations
40. 40*

    Directly search for Ultra-High Energy WIMPs at IceCube

    Ye Xu🇨🇳

    I study the possibility of directly detecting Ultra-high energy (UHE from now on) WIMPs by the IceCube experiment, via the WIMPs interaction with the nuclei in the ice. I evaluate galactic and extragalactic UHE WIMP and astrophysical and atmospheric neutrino event rates at energy range of 10 TeV - 10 PeV. I assume UHE WIMPs $\chi$ are only from the decay of superheavy dark matter $\varphi$, that is $\varphi \to \chi \bar{\chi }$. If the lifetime of superheavy dark matter ${\tau }_{\varphi }$ is taken to be $5\times 10^{21}$s, WIMPs can be detected at energies above O(40-100)TeV in this detection. Since UHE WIMP fluxes are actually depended on ${\tau }_{\varphi }$, if superheavy dark matter can decay to standard model particles (that is ${\tau }_{\varphi }$ is constrained to be larger than O($10^{26}$-$10^{29}$)s), UHE WIMPs could not be detected by IceCube.

    ↳ astro-ph.HEhep-phPhys.Dark Univ.(2019)·3 citations
41. 41*

    Surface tension of hot and dense quark matter under strong magnetic fields

    G. Lugones🇧🇷 · A. G. Grunfeld🇦🇷

    We study the surface tension of hot, highly magnetized three flavor quark matter droplets, focusing specifically on the thermodynamic conditions prevailing in neutron stars, hot lepton rich protoneutron stars and neutron star mergers. We explore the role of temperature, baryon number density, trapped neutrinos, droplet size and magnetic fields within the multiple reflection expansion formalism (MRE), assuming that astrophysical quark matter can be described as a mixture of free Fermi gases composed by quarks $u$, $d$, $s$, electrons and neutrinos, in chemical equilibrium under weak interactions. We find that the total surface tension is rather unaffected by the size of the drop, but is quite sensitive to the effect of baryon number density, temperature, trapped neutrinos and magnetic fields (specially above $eB\sim 5\times 10^{-3}{\mathrm{GeV}}^2$). Surface tensions parallel and transverse to the magnetic field span values up to $\sim$ 25 MeV/fm${}^2$. For $T\lesssim 100$ MeV the surface tension is a decreasing function of temperature but above 100 MeV it increases monotonically with $T$. Finally, we discuss some astrophysical consequences of our results.

    ↳ astro-ph.HEhep-phnucl-thPRC(2019)·38 citations
42. 42*

    Topology change and nuclear symmetry energy in compact-star matter

    Xiang-Hai Liu🇨🇳 · Yong-Liang Ma🇨🇳 · Mannque Rho🇫🇷

    We show that the cusp-like structure in the nuclear symmetry energy, a consequence of topology change, visible in the skyrmion lattice description of dense matter is extremely robust. It is present in the Skyrme model -- with the pion field only -- and is left unscathed by massive degrees of freedom such as the vector mesons $\rho$ and $\omega$ and also the scalar meson introduced as a dilaton. It leads to the emergence of parity-doubling at the skyrmion-half-skyrmion transition and impacts on the nuclear symmetry energy "wilderness" landscape, weeding out roughly half of the wilderness. It is shown that a pseudo-conformal sound velocity arises at a precocious density at which the cusp is formed. It is suggested that the topology change, being robust, could impact on the tidal deformability observed in gravity waves

    ↳ nucl-thhep-phPRC(2019)·8 citations
43. 43*

    Calculating the $\rho$ radiative decay width with lattice QCD

    Luka Leskovec🇺🇸 · Constantia Alexandrou🇨🇾 · Stefan Meinel🇺🇸 · John W. Negele🇺🇸 · Srijit Paul🇨🇾 · Marcus Petschlies🇩🇪 · Andrew Pochinsky🇺🇸 · Gumaro Rendon🇺🇸 · Sergey Syritsyn🇺🇸

    We present the results of our lattice QCD study of the $\pi \gamma \to \pi \pi$ process, where the $\rho$ resonance appears as an enhancement in the transition amplitude. We use $N_f=2+1$ clover fermions on a lattice of $L=3.6$ fm and a pion mass of $320$ MeV. Using a combination of forward, stochastic, and sequential propagators, we calculate the two-point and three-point functions that allow us to determine the $\pi \gamma \to \pi \pi$ matrix elements for several values of the invariant mass $s$ and momentum transfer $q^2$. To fit the $q^2$ and $s$ dependence of the $\pi \gamma \to \pi \pi$ amplitude, we explore a set of general parametrizations based on a Taylor expansion. By analytic continuation to the complex pole corresponding to the $\rho$ resonance, we determine the resonant form factors and calculate the radiative decay width of the $\rho$.

    ↳ hep-lathep-phPoS(2018)·1 citation
44. 44*

    Local meson-baryon coupled-channels potential for the Lambda(1405)

    Kenta Miyahara🇯🇵 · Tetsuo Hyodo🇯🇵 · Wolfram Weise🇩🇪

    A local coupled-channels Kbar N-pi Sigma-pi Lambda potential is constructed, equivalently reproducing the scattering amplitude in chiral SU(3) dynamics. By analyzing the wave function of the Lambda(1405), we show the Kbar N dominance of the upper pole within the two-pole structure of the Lambda(1405). The resulting potential will be useful for investigating Kbar few-nucleon systems including their coupled channels.

    ↳ nucl-thhep-ph0 citations
45. 45*

    Letter of Intent for FASER: ForwArd Search ExpeRiment at the LHC

    FASER Collaboration · Akitaka Ariga · Tomoko Ariga · Jamie Boyd · David W. Casper · Jonathan L. Feng · Iftah Galon · Shih-Chieh Hsu · Felix Kling · Hidetoshi Otono · Brian Petersen · Osamu Sato and 3 other authors

    FASER is a proposed small and inexpensive experiment designed to search for light, weakly-interacting particles at the LHC. Such particles are dominantly produced along the beam collision axis and may be long-lived, traveling hundreds of meters before decaying. To exploit both of these properties, FASER is to be located along the beam collision axis, 480 m downstream from the ATLAS interaction point, in the unused service tunnel TI18. We propose that FASER be installed in TI18 in Long Shutdown 2 in time to collect data from 2021-23 during Run 3 of the 14 TeV LHC. FASER will detect new particles that decay within a cylindrical volume with radius R= 10 cm and length L = 1.5 m. With these small dimensions, FASER will complement the LHC's existing physics program, extending its discovery potential to a host of new particles, including dark photons, axion-like particles, and other CP-odd scalars. A FLUKA simulation and analytical estimates have confirmed that numerous potential backgrounds are highly suppressed at the FASER location, and the first in situ measurements are currently underway. We describe FASER's location and discovery potential, its target signals and backgrounds, the detector's layout and components, and the experiment's preliminary cost estimate, funding, and timeline.

    ↳ physics.ins-dethep-exhep-ph131 citations
46. 46*

    Euclidean partons?

    Giancarlo Rossi🇮🇹 · Massimo Testa🇮🇹

    In this talk we reexamine the possibility of evaluating parton distribution functions from lattice simulations. We show that, while in principle individual moments can be extracted from lattice data, in all cases the process of renormalization, hindered by lattice momenta limitation, represents an obstruction to a direct calculation of the full parton distribution function from QCD simulations. We discuss the case of the Ji quasi-parton distribution functions, the possibility of using the reduced Ioffe-time distributions and the more recent proposal of directly subtracting power divergent mixings in perturbation theory.

    ↳ hep-lathep-phPoS(2018)·1 citation
47. 47*

    Variational Autoencoders for New Physics Mining at the Large Hadron Collider

    Olmo Cerri🇺🇸 · Thong Q. Nguyen🇺🇸 · Maurizio Pierini🇨🇭 · Maria Spiropulu🇺🇸 · Jean-Roch Vlimant🇺🇸

    Using variational autoencoders trained on known physics processes, we develop a one-sided threshold test to isolate previously unseen processes as outlier events. Since the autoencoder training does not depend on any specific new physics signature, the proposed procedure doesn't make specific assumptions on the nature of new physics. An event selection based on this algorithm would be complementary to classic LHC searches, typically based on model-dependent hypothesis testing. Such an algorithm would deliver a list of anomalous events, that the experimental collaborations could further scrutinize and even release as a catalog, similarly to what is typically done in other scientific domains. Event topologies repeating in this dataset could inspire new-physics model building and new experimental searches. Running in the trigger system of the LHC experiments, such an application could identify anomalous events that would be otherwise lost, extending the scientific reach of the LHC.

    ↳ hep-excs.LGhep-phJHEP(2019)·162 citations
48. 48*

    Fluctuating shapes of the fireballs in heavy-ion collisions

    Boris Tomasik🇸🇰 · Jakub Cimerman🇨🇿 · Renata Kopecna🇩🇪 · Martin Schulc🇨🇿

    We argue that energy and momentum deposition from hard partons into quark-gluon plasma induces an important contribution to the final state hadron anisotropies. We also advocate a novel method of Event Shape Sorting which allow to analyse the azimuthal anisotropies of the fireball dynamics in more detail. A use of the method in femtoscopy is demonstrated.

    ↳ nucl-thhep-exhep-phEPJ Web Conf.(2019)·1 citation
49. 49*

    All two-loop MHV remainder functions in multi-Regge kinematics

    Vittorio Del Duca🇨🇭 · Claude Duhr🇨🇭 · Falko Dulat🇺🇸 · Brenda Penante🇨🇭

    We introduce a method to extract the symbol of the coefficient of $(2\pi i{)}^2$ of MHV remainder functions in planar N=4 Super Yang-Mills in multi-Regge kinematics region directly from the symbol in full kinematics. At two loops this symbol can be uplifted to the full function in a unique way, without any beyond-the-symbol ambiguities. We can therefore determine all two-loop MHV amplitudes at function level in all kinematic regions with different energy signs in multi-Regge kinematics. We analyse our results and we observe that they are consistent with the hypothesis of a contribution from the exchange of a three-Reggeon composite state starting from two loops and eight points in certain kinematic regions.

    ↳ hep-thhep-phJHEP(2019)·17 citations
50. 50*

    Quark-hadron continuity beyond Ginzburg-Landau paradigm

    Yuji Hirono🇰🇷 · Yuya Tanizaki🇺🇸

    Quark-hadron continuity is a scenario that hadronic matter is continuously connected to color superconductor without phase transitions as the baryon chemical potential increases. This scenario is based on Landau's classification of phases since they have the same symmetry breaking pattern. We address the question whether this continuity is true as quantum phases of matter, which requires the treatment beyond Ginzburg-Landau description. To examine the topological nature of color superconductor, we derive a dual effective theory for $U(1)$ Nambu-Goldstone (NG) bosons and vortices of the color-flavor locked phase, and discuss the fate of emergent higher-form symmetries. The theory has the form of a topological $BF$ theory coupled to NG bosons, and fractional statistics of test quarks and vortices arises as a result of an emergent ${\mathbb{Z}}_3$ two-form symmetry. We find that this symmetry cannot be spontaneously broken, indicating that quark-hadron continuity is still a consistent scenario.

    ↳ hep-thcond-mat.str-elhep-phnucl-thPRL(2019)·57 citations
51. 51*

    Hidden Sectors in String Theory: Kinetic Mixings, Fifth Forces and Quintessence

    Bobby Samir Acharya🇬🇧 · Anshuman Maharana🇮🇳 · Francesco Muia🇮🇹

    Light moduli fields in string compactifications can have interesting implications for particle physics and cosmology. Fifth force bounds impose stringent constraints on the interactions of such moduli with the visible sector. To be consistent with the bounds, they need to be part of hidden sectors which interact with the Standard Model with weaker-than-Planck suppressed interactions. We consider scenarios in which the visible sector degrees of freedom are localised in the compactification and light moduli arise as closed string degrees of freedom associated with hidden sectors which are geometrically separated (in the extra-dimensions) from the Standard Model. Kinetic mixings lead to interactions between the moduli and the visible sector - we compute these using Kaehler potentials of string/M-theory compactifications. We argue that in general these interactions provide a lower bound on the strength of the interactions between the moduli and the visible sector. The interactions scale with inverse powers of the volume of the compactification, thus fifth force bounds can be translated to lower bounds on the volume of the extra-dimensions. We find that compactification volumes have to be large to evade the bounds. This imposes interesting constraints on quintessence model building in string theory. Our results for the strength of the interactions can also be used to quantify the fine-tuning necessary for the stability of the potential of a light modulus against quantum corrections involving visible sector loops.

    ↳ hep-thhep-phJHEP(2019)·53 citations
52. 52*

    The overdamped chiral magnetic wave

    I. A. Shovkovy🇺🇸 · D. O. Rybalka🇺🇸 · E. V. Gorbar🇺🇦

    About eight years ago it was predicted theoretically that a charged chiral plasma could support the propagation of the so-called chiral magnetic waves, which are driven by the anomalous chiral magnetic and chiral separation effects. This prompted intensive experimental efforts in search of signatures of such waves in relativistic heavy-ion collisions. In fact, several experiments have already reported a tentative detection of the predicted signal, albeit with a significant background contribution. Here, we critically reanalyze the theoretical foundations for the existence of the chiral magnetic waves. We find that the commonly used background-field approximation is not sufficient for treating the waves in hot chiral plasmas in the long-wavelength limit. Indeed, the back-reaction from dynamically induced electromagnetic fields turns the chiral magnetic wave into a diffusive mode. While the situation is slightly better in the strongly-coupled near-critical regime of quark-gluon plasma created in heavy-ion collisions, the chiral magnetic wave is still strongly overdamped due to the effects of electrical conductivity and charge diffusion.

    ↳ nucl-thhep-phhep-thPoS(2018)·17 citations
53. 53*

    Cross Sections for A(e,e')X Reactions

    U. Mosel🇩🇪 · K. Gallmeister🇩🇪

    Recent JLAB measurements of inclusive (e,A) cross sections as a function of outgoing lepton momentum may provide information on the nucleon spectral function in targets that will be relevant for the planned DUNE neutrino long-baseline experiment. They also provide an important testing ground for neutrino generators. We have therefore used the transport theoretical framework and code GiBUU to calculate the cross sections for the targets C, Ar and Ti. We compare the calculations with the experimental data. The overall agreement is good. Relatively small discrepancies appear mainly on the low-electronenergy side of the QE-peak where QE and 2p2h excitation processes overlap.

    ↳ nucl-exhep-exhep-phnucl-thPRC(2019)·14 citations
54. 54*

    Jet Substructure Variables with the SiFCC Detector at 100 TeV

    C.-H Yeh🇹🇼 · S.V. Chekanov🇺🇸 · A.V. Kotwal🇺🇸 · J. Proudfoot🇺🇸 · S. Sen🇺🇸 · N.V. Tran🇺🇸 · S.-S Yu🇹🇼

    Future experiments beyond the LHC era will measure high-momentum bosons ($W$, $Z$, $H$) and top quarks with strongly collimated decay products that form hadronic jets. This paper describes the studies of the performance of jet substructure variables using the Geant4 simulation of a detector designed for high energy $pp$ collisions at a 100 TeV collider. The two-prong jets from $Z^{\prime }\to WW$ and three-prong jets from $Z^{\prime }\to t\bar{t}$ are compared with the background from light quark jets, assuming $Z^{\prime }$ masses in the range 5 -- 40 TeV. Our results indicate that the performance of jet-substructure reconstruction improves with reducing transverse cell sizes of a hadronic calorimeter from $\Delta \eta \times \Delta \varphi =0.087\times 0.087$ to $0.022\times 0.022$ in most cases.

    ↳ hep-exhep-phPoS(2019)·1 citation

* 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.