Fri·Aug 9, 2019Friday·August 9, 2019

1. 01*

   Zee-Burst: A New Probe of Neutrino Non-Standard Interactions at IceCube

   K. S. Babu🇺🇸 · P. S. Bhupal Dev🇺🇸 · Sudip Jana🇺🇸 · Yicong Sui🇺🇸

   We propose a new way to probe non-standard interactions (NSI) of neutrinos with matter using the ultra-high energy (UHE) neutrino data at current and future neutrino telescopes. We consider the Zee model of radiative neutrino mass generation as a prototype, which allows two charged scalars -- one $SU(2{)}_L$-doublet and one singlet, both being leptophilic, to be as light as 100 GeV, thereby inducing potentially observable NSI with electrons. We show that these light charged Zee-scalars could give rise to a Glashow-like resonance feature in the UHE neutrino event spectrum at the IceCube neutrino observatory and its high-energy upgrade IceCube-Gen2, which can probe a sizable fraction of the allowed NSI parameter space.

   hep-phastro-ph.HEhep-exPRL(2020)·29 citations
2. 02*

   Entropy production in pp and Pb-Pb collisions at energies available at the CERN Large Hadron Collider

   Patrick Hanus🇩🇪 · Aleksas Mazeliauskas🇨🇭 · Klaus Reygers🇩🇪

   We use experimentally measured identified particle spectra and Hanbury Brown-Twiss radii to determine the entropy per unit rapidity $dS/dy$ produced in $\sqrt{s}=7$ TeV pp and $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV Pb-Pb collisions. We find that $dS/dy=11335\pm 1188$ in 0-10% Pb-Pb, $dS/dy=135.7\pm 17.9$ in high-multiplicity pp, and $dS/dy=37.8\pm 3.7$ in minimum bias pp collisions and compare the corresponding entropy per charged particle $(dS/dy)/(d{N}_{\mathrm{ch}}/dy)$ to predictions of statistical models. Finally, we use the QCD kinetic theory pre-equilibrium and viscous hydrodynamics to model entropy production in the collision and reconstruct the average temperature profile at ${\tau }_0=1$ fm/$c$ for high multiplicity pp and Pb-Pb collisions.

   hep-phnucl-exnucl-thPRC(2019)·39 citations
3. 03*

   Branching Fractions of the $X(3872)$

   Eric Braaten🇺🇸 · Li-Ping He🇺🇸 · Kevin Ingles🇺🇸

   The recoil momentum spectrum from the decay $B^{+}\to K^{+}+\mathrm{anything}$ has recently been measured by the BaBar collaboration. The spectrum has a peak with invariant mass near the mass of the $X(3872)$ meson. The preliminary measurement by the BaBar collaboration implies that its branching fraction into $J/\psi {\pi }^{+}{\pi }^{-}$ is about 4\%. We emphasize that this is the branching fraction for the entire resonance feature from $B^{+}$-to-$K^{+}$ transitions, which includes a $D^{\ast 0}{\bar{D}}^0$ and $D^0{\bar{D}}^{\ast 0}$ threshold enhancement as well as a possible bound state below the threshold or a virtual state. If the $X$ is a bound state of charm mesons, its branching fraction into $J/\psi {\pi }^{+}{\pi }^{-}$ should be considerably larger than that of the $X$ resonance feature. We use measurements of branching ratios of the $X$ to put an upper bound on this branching fraction of 33\%. We also constrain the parameters of the simplest plausible model for the line shapes of the $X$ using the precise measurement of the resonance energy of the $X$ and an estimate of the branching fraction into $D^0{\bar{D}}^0{\pi }^0$ and $D^0{\bar{D}}^0\gamma$ from the $X$ resonance feature from $B^{+}$-to-$K^{+}$ transitions.

   hep-ph20 citations
4. 04*

   Reevaluating Uncertainties in $\bar{B}\to X_s\gamma$ Decay

   Ayesh Gunawardana🇺🇸 · Gil Paz🇺🇸

   The rare decay $\bar{B}\to X_s\gamma$ is an important probe of physics beyond the standard model. The largest uncertainty on the total rate and the CP asymmetry arises from resolved photon contributions. These appear first at order $1/m_b$ and are related to operators other than $Q_{7\gamma }$ in the effective weak Hamiltonian. One of the three leading contributions, $Q_1^q-Q_{7\gamma }$, is described by a non-local function whose moments are related to HQET parameters. We use recent progress in our knowledge of these parameters to reevaluate the resolved photon contribution to $\bar{B}\to X_s\gamma$ total rate and CP asymmetry.

   hep-phhep-exJHEP(2019)·39 citations
5. 05*

   Dirac neutrinos in a $SU(2)$ left-right symmetric model

   Henry Diaz Chavez🇵🇪 · V. Pleitez🇧🇷 · O. P. Ravinez🇵🇪

   In a left-right symmetric model, with the scalar sector consisting of several bi-doublets and two doublets, neutrinos remain as Dirac fermions in all order in perturbation theory. Although with only two bi-doublets the neutrino masses need still a fine tuning, this is not the case when a third bi-doublet is added. One of the scalar doublet may be of the inert type since it is protected by the left-right symmetry.

   hep-phhep-exPRD(2020)·9 citations
6. 06*

   Lepton-Trijet and Displaced Vertex Searches for Heavy Neutrinos at Future Electron-Proton Colliders

   Stefan Antusch🇨🇭 · Oliver Fischer🇩🇪 · A. Hammad🇨🇭

   Electron proton (ep) colliders could provide particle collisions at TeV energies with large data rates while maintaining the clean and pile~up-free environment of lepton colliders, which makes them very attractive for heavy neutrino searches. Heavy (mainly sterile) neutrinos with masses around the electroweak scale are proposed in low scale seesaw models for neutrino mass generation. In this paper, we analyse two of the most promising signatures of heavy neutrinos at ep colliders, the lepton-flavour violating (LFV) lepton-trijet signature and the displaced vertex signature. In the considered benchmark model, we find that for heavy neutrino masses around a few hundred GeV, the LFV lepton-trijet signature at ep colliders yields the best sensitivity of all currently discussed heavy neutrino signatures (analysed at the reconstructed level) up to now.

   hep-phJHEP(2020)·44 citations
7. 07*

   Hydrodynamic attractors, initial state energy and particle production in relativistic nuclear collisions

   Giuliano Giacalone🇫🇷 · Aleksas Mazeliauskas🇨🇭 · Sören Schlichting🇩🇪

   We exploit the concept of hydrodynamic attractors to establish a general relation between the initial state energy and the produced particle multiplicities in high-energy nuclear collisions. When combined with an ab initio model of energy deposition, the entropy production during the pre-equilibrium phase naturally explains the universal centrality dependence of the measured charged particle yields in nucleus-nucleus collisions. We further estimate the energy density of the far-from-equilibrium initial state and discuss how our results can be used to constrain non-equilibrium properties of the quark-gluon plasma.

   hep-phnucl-exnucl-thPRL(2019)·125 citations
8. 08*

   Heavy baryon production with an instanton interaction

   Sang-In Shim🇯🇵 · Atsushi Hosaka🇯🇵 · Hyun-Chul Kim🇰🇷

   We propose a new reaction mechanism for the study of strange and charmed baryon productions. In this mechanism we consider the correlation of two quarks in baryons, so it can be called the two-quark process. As in the previously studied one-quark process, we find large production rates for charmed baryons in comparison with strange baryons. Moreover, the new mechanism causes the excitation of both the $\rho$ mode and the $\lambda$ mode. Using the wave functions for baryons from a quark model, we compute the production rates of various baryon states. We find that the production rates reflect the structure of the wave functions that imply the usefulness of the reactions for the study of baryon structures.

   hep-phhep-exPTEP(2020)·5 citations
9. 09*

   Transcendental structure of multiloop massless correlators and anomalous dimensions

   P. A. Baikov🇷🇺 · K. G. Chetyrkin🇩🇪

   We give a short account of recent advances in our understanding of the $\pi$-dependent terms in massless (Euclidean) 2-point functions as well as in generic anomalous dimensions (ADs) and $\beta$-functions. We extend the considerations of \cite{Baikov:2018wgs} by two more loops, that is for the case of 6- and 7-loop correlators and 7- and 8-loop renormalization group (RG) functions. Our predictions for the ($\pi$-dependent terms) of the 7-loop RG functions for the case of the $O(n)$ ${\varphi }^4$ theory are in full agreement with the recent results from \cite{Schnetz:2016fhy}. All available 7- and 8-loop results for QCD and the scalar $O(n)$ ${\phi }^4$ theory obtained within the large $N_f$ approach to the quantum field theory (see, e.g. \cite{Gracey:2018ame}) are also in full agreement with our results.

   hep-phhep-thJHEP(2019)·20 citations
10. 10*

    Associated $Z^{\prime }$ production in the flavorful $U(1)$ scenario for $R_{K^{(\ast )}}$

    Siddharth Dwivedi🇮🇳 · Adam Falkowski🇫🇷 · Dilip Kumar Ghosh · Nivedita Ghosh

    The flavorful $Z^{\prime }$ model with its couplings restricted to the left-handed second generation leptons and third generation quarks can potentially resolve the observed anomalies in $R_K$ and $R_{K^{\ast }}$. After examining the current limits on this model from various low-energy processes, we probe this scenario at 14 TeV high-luminosity run of the LHC using two complementary channels: one governed by the coupling of $Z^{\prime }$ to $b$-quarks and the other to muons. We also discuss the implications of the latest LHC high mass resonance searches in the dimuon channel on the model parameter space of our interest.

    hep-phEPJC(2020)·22 citations
11. 11*

    Soft corrections to inclusive DIS at four loops and beyond

    Goutam Das (DESY, Hamburg)🇩🇪 · Sven-Olaf Moch (Hamburg U., Inst. Theor. Phys. II)🇩🇪 · Andreas Vogt (Liverpool U., Dept. Math)🇬🇧

    We study the threshold corrections to the structure functions in deep-inelastic scattering (DIS) at the fifth logarithmic (N${}^4$LL) order of the soft-gluon exponentiation in massless perturbative QCD. Using recent results for the splitting functions and the quark form factor, we derive the fourth-order contribution to the coefficient $f^{\mathrm{q}}$ of the form factor and from it the N${}^4$LL part of the exponentiation coefficient $B^{\mathrm{DIS}}$ in the limit of a large number of colours. An approximation scheme is shown that leads to sufficiently accurate N${}^4$LL results for full QCD. The N${}^4$LL corrections are small and lead to a further stabilization of the perturbative expansion for the soft-gluon exponent.

    hep-phPoS(2019)·5 citations
12. 12*

    CP symmetry tests in the cascade-anticascade decay of charmonium

    Patrik Adlarson🇸🇪 · Andrzej Kupsc🇸🇪

    We analyze joint angular distributions of a charmonium decay to the $\Xi \bar{\Xi }$ pair using the $\Xi \to \Lambda \pi \to p{\pi }^{-}\pi$ weak decay chain for the cascade and the charge conjugated mode for the anticascade. The decays allow a direct comparison of the baryon and antibaryon decay properties and a sensitive test of CP symmetry in the strange baryon sector. We show that all involved decay parameters can be determined separately in vector and (pseudo)scalar charmonia decays into $\Xi \bar{\Xi }$ due to the spin correlations between the weak decay chains. Contrary to the recently measured $e^{+}{e}^{-}\to J/\psi \to \Lambda \bar{\Lambda }$ process, the transverse polarization of the cascade is not needed and has almost no impact on the uncertainties of the decay parameters.

    hep-phhep-exPRD(2019)·22 citations
13. 13*

    Viscous coefficients and thermal conductivity of a $\pi KN$ gas mixture in the medium

    Pallavi Kalikotay🇮🇳 · Nilanjan Chaudhuri🇮🇳 · Snigdha Ghosh🇮🇳 · Utsab Gangopadhyaya🇮🇳 · Sourav Sarkar🇮🇳

    The temperature and density dependence of the relaxation times, thermal conductivity, shear viscosity and bulk viscosity for a hot and dense gas consisting of pions, kaons and nucleons have been evaluated in the kinetic theory approach. The in-medium cross-sections for $\pi \pi$, $\pi K$ and $\pi N$ scatterings were obtained by using complete propagators for the exchanged $\rho$, $\sigma$, $K^{\ast }$ and $\Delta$ excitations derived using thermal field theoretic techniques. Notable deviations can be observed in the temperature dependence of $\eta$, $\zeta$ and $\lambda$ when compared with corresponding calculations using vacuum cross-sections usually employed in the literature. The value of the specific shear viscosity $\eta /s$ is found to be in agreement with available estimates.

    ↳ nucl-thhep-phEPJA(2020)·7 citations
14. 14*

    Kinetic freeze-out in central heavy-ion collisions between 7.7 and 2760 GeV per nucleon pair

    Ivan Melo🇸🇰 · Boris Tomasik🇸🇰

    We fit the single-particle $p_t$ spectra of identified pions, kaons, and (anti)protons from central collisions of gold or lead nuclei at energies between 7.7 and 2760~GeV per nucleon pair. Blast wave model with included resonance production and with an assumption of partial chemical equilibrium is used and the fits are performed with the help of a Gaussian emulator process. A kinetic freeze-out temperature is found about 100~MeV for the lowest collision energies and 80~MeV at the LHC. The average transverse expansion velocity grows with increasing $\sqrt{s_{NN}}$ from 0.45 to 0.65. Due to partial chemical equilibrium, the influence of resonance decays on the shape of the $p_t$ spectra for $\sqrt{s_{NN}}$ above 27~GeV is small.

    ↳ nucl-thhep-phnucl-exJ.Phys.G(2020)·23 citations
15. 15*

    On the impact of magnetic-field models in galaxy clusters on constraints on axion-like particles from the lack of irregularities in high-energy spectra of astrophysical sources

    Maxim Libanov🇷🇺 · Sergey Troitsky🇷🇺

    Photons may convert to axion-like particles (ALPs) in external magnetic fields. Under certain conditions, this effect should result in irregular features in observed spectra of astrophysical sources. Lack of such irregularities in particular spectra was used to constrain ALP parameters, with two most popular sources being the radio galaxy NGC 1275 and the blazar PKS 2155-304. The effect and, consequently, the constraints, depend on the magnetic fields through which the light from the source is propagated. Here, we revisit ALP constraints from gamma-ray observations of NGC 1275 taking into account the regular magnetic field of the X-ray cavity observed around this radio galaxy. This field was not accounted for in previous studies, which assumed a model of purely turbulent fields with coherence length much smaller than the cavity size. For the purely regular field, ALP constraints are relaxed considerably, compared to the purely turbulent one. While the actual magnetic field around a source is an unknown sum of the turbulent and ordered components, the difference in results gives an estimate of the theoretical uncertainty of the study and calls for detailed measurements of magnetic fields around sources used to constrain ALP properties in this approach.

    ↳ astro-ph.HEhep-phPLB(2020)·64 citations
16. 16*

    Quantifying the impacts of future gravitational-wave data on constraining interacting dark energy

    Hai-Li Li🇨🇳 · Dong-Ze He🇨🇳 · Jing-Fei Zhang🇨🇳 · Xin Zhang🇨🇳

    In this work, we investigate the impacts of the future gravitational-wave (GW) standard siren observation by the Einstein Telescope (ET) on constraining the interacting dark energy (IDE) models. We simulate 1000 GW events in the redshift range of $0\lesssim z\lesssim 5$ based on the 10-year observation of the ET. We combine the simulated GW data with the current mainstream cosmological electromagnetic observations including the cosmic microwave background anisotropies, the baryon acoustic oscillations, and the type Ia supernovae to constrain the IDE models. We consider typical IDE models in the context of a perturbed universe. To avoid the large-scale instability problem for IDE models, we apply the extended parameterized post-Friedmann approach to calculate the cosmological perturbations. We find that the addition of the GW standard siren data could significantly improve the constraint accuracies for most of the cosmological parameters (e.g., $H_0$, $w$, and ${\Omega }_{\mathrm{m}}$). For the coupling parameter $\beta$, the constraint errors could also be slightly improved when adding the GW data in the cosmological fit.

    ↳ astro-ph.COgr-qchep-phJCAP(2020)·49 citations
17. 17*

    Simulating Binary Neutron Stars with Hybrid Equation of States: Gravitational Waves, Electromagnetic Signatures, and Challenges for Numerical Relativity

    Henrique Gieg🇧🇷 · Tim Dietrich🇳🇱 · Maximiliano Ujevic🇧🇷

    The gravitational wave and electromagnetic signatures connected to the merger of two neutron stars allow us to test the nature of matter at supranuclear densities. Since the Equation of State governing the interior of neutron stars is only loosely constrained, there is even the possibility that strange quark matter exists inside the core of neutron stars. We investigate how strange quark matter cores affect the binary neutron star coalescence by performing numerical relativity simulations. Interestingly, the strong phase transition can cause a reduction of the convergence order of the numerical schemes to first order if the numerical resolution is not high enough. Therefore, an additional challenge is added in producing high-quality gravitational wave templates for Equation of States with a strong phase transition. Focusing on one particular configuration of an equal mass configuration consistent with GW170817, we compute and discuss the associated gravitational wave signal and some of the electromagnetic counterparts connected to the merger of the two stars. We find that existing waveform approximants employed for the analysis of GW170817 allow describing this kind of systems within the numerical uncertainties, which, however, are several times larger than for pure hadronic Equation of States, which means that even higher resolutions have been employed for an accurate gravitational wave model comparison. We also show that for the chosen Equation of State, quasi-universal relations describing the gravitational wave emission after the moment of merger seem to hold and that the electromagnetic signatures connected to our chosen setup would not be bright enough to explain the kilonova associated to GW170817.

    ↳ gr-qcastro-ph.HEhep-phParticles(2019)·26 citations
18. 18*

    QCD in the heavy dense regime for general $N_c$: On the existence of quarkyonic matter

    Owe Philipsen🇩🇪 · Jonas Scheunert🇩🇪

    Lattice QCD with heavy quarks reduces to a three-dimensional effective theory of Polyakov loops, which is amenable to series expansion methods. We analyse the effective theory in the cold and dense regime for a general number of colours, $N_c$. In particular, we investigate the transition from a hadron gas to baryon condensation. For any finite lattice spacing, we find the transition to become stronger, i.e. ultimately first-order, as $N_c$ is made large. Moreover, in the baryon condensed regime, we find the pressure to scale as $p\sim N_c$ through three orders in the hopping expansion. Such a phase differs from a hadron gas with $p\sim N_c^0$, or a quark gluon plasma, $p\sim N_c^2$, and was termed quarkyonic in the literature, since it shows both baryon-like and quark-like aspects. A lattice filling with baryon number shows a rapid and smooth transition from condensing baryons to a crystal of saturated quark matter, due to the Pauli principle, and is consistent with this picture. For continuum physics, the continuum limit needs to be taken before the large $N_c$ limit, which is not yet possible in practice. However, in the controlled range of lattice spacings and $N_c$-values, our results are stable when the limits are approached in this order. We discuss possible implications for physical QCD.

    ↳ hep-lathep-phnucl-thJHEP(2019)·39 citations
19. 19*

    Sum Rule of Femtoscopic Correlation Function

    Radoslaw Maj🇵🇱 · Stanislaw Mrowczynski🇵🇱

    A correlation function of two particles with small relative velocities obeys a sum rule - the momentum integral of the function is determined due to the completeness of quantum states of the particles. The original sum rule derived in 1995 suffered from a serious problem: the momentum integral was ultraviolet divergent in physically interesting cases. We resolve the problem by considering the sum rule not of a single correlation function but of a sum or difference of two appropriately chosen correlation functions. The improved sum rule is shown to work well for the exact Coulomb correlation functions. We argue that the sum rule can be used to test an accuracy and range of applicability of correlation functions computed in approximate models. The neutron-proton correlation function is discussed as an example.

    ↳ nucl-thhep-phPRC(2020)·5 citations
20. 20*

    Towards analog quantum simulations of lattice gauge theories with trapped ions

    Zohreh Davoudi🇺🇸 · Mohammad Hafezi🇺🇸 · Christopher Monroe🇺🇸 · Guido Pagano🇺🇸 · Alireza Seif🇺🇸 · Andrew Shaw🇺🇸

    Gauge field theories play a central role in modern physics and are at the heart of the Standard Model of elementary particles and interactions. Despite significant progress in applying classical computational techniques to simulate gauge theories, it has remained a challenging task to compute the real-time dynamics of systems described by gauge theories. An exciting possibility that has been explored in recent years is the use of highly-controlled quantum systems to simulate, in an analog fashion, properties of a target system whose dynamics are difficult to compute. Engineered atom-laser interactions in a linear crystal of trapped ions offer a wide range of possibilities for quantum simulations of complex physical systems. Here, we devise practical proposals for analog simulation of simple lattice gauge theories whose dynamics can be mapped onto spin-spin interactions in any dimension. These include 1+1D quantum electrodynamics, 2+1D Abelian Chern-Simons theory coupled to fermions, and 2+1D pure Z2 gauge theory. The scheme proposed, along with the optimization protocol applied, will have applications beyond the examples presented in this work, and will enable scalable analog quantum simulation of Heisenberg spin models in any number of dimensions and with arbitrary interaction strengths.

    ↳ quant-phhep-lathep-phnucl-th+1PRResearch(2020)·165 citations
21. 21*

    Gravitational Waves from Holographic Neutron Star Mergers

    Christian Ecker🇳🇱 · Matti Järvinen🇳🇱 · Govert Nijs🇳🇱 · Wilke van der Schee🇨🇭

    We simulate the merger of binary neutron stars and analyze the spectral properties of their gravitational waveforms. For the stars we construct hybrid equations of state (EoSs) with a standard nuclear matter EoS at low densities, transitioning to a state-of-the-art holographic EoS in the otherwise intractable high density regime. Depending on the transition density the characteristic frequencies in the spectrum produced from the hybrid EoSs are shifted to significantly lower values as compared to the pure nuclear matter EoS. The highest rest-mass density reached outside a possible black hole horizon is approximately $1.1\cdot 10^{15}$ g/cm${}^3$, which for the holographic model is below the density of the deconfined quark matter phase.

    ↳ astro-ph.HEgr-qchep-phhep-th+1PRD(2020)·81 citations
22. 22*

    Evidences of low-diffusion bubbles around Galactic pulsars

    Mattia Di Mauro🇺🇸 · Silvia Manconi🇮🇹 · Fiorenza Donato🇮🇹

    Recently, a few-degrees extended $\gamma$-ray halo in the direction of Geminga pulsar has been detected by HAWC, Milagro and Fermi-LAT. These observations can be interpreted with positrons ($e^{+}$) and electrons ($e^{-}$) accelerated by Geminga pulsar wind nebula (PWN), released in a Galactic environment with a low diffusion coefficient ($D_0$), and inverse Compton scattering (ICS) with the interstellar radiation fields. We inspect here how the morphology of the ICS $\gamma$-ray flux depends on the energy, the pulsar age and distance, and the strength and extension of the low-diffusion bubble. In particular we show that $\gamma$-ray experiments with a peak of sensitivity at TeV energies are the most promising ones to detect ICS halos. We perform a study of the sensitivity of HAWC, HESS and the future CTA experiment finding that, with efficiencies of the order of a few %, the first two experiments should have already detected a few tens of ICS halos while the latter will increase the number of detections by a factor of 4. We then consider a sample of sources associated to PWNe and detected in the HESS Galactic plane survey and in the second HAWC catalog. We use the information available in these catalogs for the $\gamma$-ray spatial morphology and flux of these sources to inspect the value of $D_0$ around them and the $e^{\pm }$ injection spectrum. All sources are detected as extended with a $\gamma$-ray emission extended about $15-80$ pc. Assuming that most of the $e^{\pm }$ accelerated by these sources have been released in the interstellar medium, the diffusion coefficient is $2-30\cdot 10^{26}$ cm${}^2$/s at 1 TeV, i.e. two orders of magnitude smaller than the value considered to be the average in the Galaxy. These observations imply that Galactic PWNe have low-diffusion bubbles with a size of at least 80 pc.

    ↳ astro-ph.HEhep-phPRD(2020)·77 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.