Fri·Sep 27, 2019Friday·September 27, 2019

1. 01*

   Terrestrial and Martian Heat Flow Limits on Dark Matter

   Joseph Bramante🇨🇦 · Andrew Buchanan🇨🇦 · Alan Goodman🇨🇦 · Eesha Lodhi🇨🇦

   If dark matter is efficiently captured by a planet, energy released in its annihilation can exceed that planet's total heat output. Building on prior work, we treat Earth's composition and dark matter capture in detail and present improved limits on dark matter-nucleon scattering cross sections for dark matter masses ranging from 0.1 to $10^{10}$ GeV. We also extend Earth limits by applying the same treatment to Mars. The scope of dark matter models considered is expanded to include spin-dependent nuclear interactions including isospin-independent, proton only, and neutron only interactions. We find that Earth and Mars heating bounds are alleviated for dark matter s-wave self-annihilation cross sections $\lesssim 10^{-44}\mathrm{c}{\mathrm{m}}^2$.

   hep-phastro-ph.EPhep-exPRD(2020)·59 citations
2. 02*

   Axion scales and couplings with Stückelberg mixing

   Kiwoon Choi🇰🇷 · Chang Sub Shin🇰🇷 · Seokhoon Yun🇰🇷

   We study the axion field range and low energy couplings in models with Stückelberg mixing between axions and $U(1)$ gauge bosons. It is noted that the gauge-invariant axion combination $\xi$ in the model is periodic $modulo$ an appropriate shift of gauge-variant axions eaten by the massive $U(1)$ gauge bosons, which in some cases makes the connection between the field range and the low energy couplings less transparent. We derive the field range of $\xi$ for generic forms of the axion kinetic metric and $U(1)$ charges, and identify the field basis for which all non-derivative couplings of $\xi$ are quantized in a manner manifestly consistent with the periodicity of $\xi$. Generically Stückelberg mixing reduces the axion field range. In particular, the mixings between $N$ axions and $(N-1)$ $U(1)$ gauge bosons typically result in an exponentially reduced field range $M_{\xi }=\mathcal{O}\left(k^{-(N-1)}f/\sqrt{N!}\right)$ for the residual gauge-invariant axion $\xi$ in the limit $N\gg 1$, where $f$ and $k$ denote the typical decay constant and the root mean square of the $U(1)$ gauge charges of the original $N$ axions. Using simple examples, we study also the reparameterization-invariant physical quantities such as the axion effective potential and 1PI couplings to gauge bosons, which are determined by the reparameterization-dependent axion couplings in the model.

   hep-phhep-thJHEP(2019)·9 citations
3. 03*

   Revisiting (s)neutrino dark matter in natural SUSY

   T. Faber🇩🇪 · J. Jones-Pérez🇵🇪 · Y. Liu🇩🇪 · W. Porod🇩🇪

   We study natural supersymmetric scenarios with light right-handed neutrino superfields, and consider the possibility of having either a neutrino or a sneutrino as a dark matter candidate. For the former, we evaluate the possibility of having SUSY corrections on the ${\nu }_4\to {\nu }_{\ell }\gamma$ decay rate, such that the NuStar bounds are relaxed. We find that corrections are too small. For sneutrino dark matter, we consider thermal and non-thermal production, taking into account freeze-out, freeze-in and super-WIMP mechanisms. For the non-thermal case, we find that the ${\tilde{\nu }}_R$ can reproduce the observed relic density by adjusting the R-sneutrino mass and Yukawa couplings. For the thermal case, we find the need to extend the model in order to enhance sneutrino annihilations, which we exemplify in a model with an extended gauge symmetry.

   hep-phPRD(2020)·15 citations
4. 04*

   A $U(1{)}_X$ extension to the SM with three families and Peccei Quinn symmetry

   Y.A. Garnica🇨🇴 · R. Martinez🇺🇸

   We propose a non-universal $U(1{)}_X$ extension to the Standard Model with three families and an additional global anomala Peccei-Quinn (PQ) symmetry. The breaking of the former allows us to give masses to the exotic fermionic sector and the later generates the necessary zeros in the mass matrices to explain the fermionic mass hierarchy. In addition, the large energy scale associated with the spontaneously breaking (SSB) of the PQ symmetry provides a solution to the strong CP-problem and an axion that could be a possible dark matter candidate. Also, the SSB allows to generate right-handed neutrino masses, so the active neutrinos acquire $eV$-mass values due to the see-saw mechanism implementation.

   hep-ph0 citations
5. 05*

   Non-perturbative renormalization of the Yang-Mills beta functions

   Renata Jora🇷🇴 · Salah Nasri🇦🇪

   We determine the non-perturbative corrections to the gauge coupling constant and the topological charge in the Yang Mills theory. The method makes no explicit use of instanton calculations but instead relies on boundary properties of the quantum partition function. The approach may offer important clues regarding the behavior of the coupling constant and the theta angle for other gauge theories like QCD and supersymmetric QCD.

   hep-phhep-thRom.J.Phys.(2021)·0 citations
6. 06*

   ${\chi }_{c1}$ decays into a pseudoscalar meson and a vector-vector molecule

   Natsumi Ikeno🇨🇳 · Jorgivan M. Dias🇨🇳 · Wei-Hong Liang🇨🇳 · Eulogio Oset🇪🇸

   We evaluate ratios of the ${\chi }_{c1}$ decay rates to $\eta$ (${\eta }^{\prime },K^{-}$) and one of the $f_0(1370)$, $f_0(1710)$, $f_2(1270)$, $f_2^{\prime }(1525)$, $K_2^{\ast }(1430)$ resonances, which in the local hidden gauge approach are dynamically generated from the vector-vector interaction. With the simple assumption that the ${\chi }_{c1}$ is a singlet of SU(3), and the input from the study of these resonances as vector-vector molecular states, we describe the experimental ratio $\mathcal{B}({\chi }_{c1}\to \eta f_2(1270))/\mathcal{B}({\chi }_{c1}\to {\eta }^{\prime }{f}_2^{\prime }(1525))$ and make predictions for six more ratios that can be tested in future experiments.

   hep-phPRD(2019)·8 citations
7. 07*

   Study of the dilepton electromagnetic decays of ${\chi }_{cJ}(1P)$

   Xuan-He Wang🇨🇳 · Yue Jiang🇨🇳 · Tianhong Wang🇨🇳 · Xiao-Ze Tan🇨🇳 · Geng Li🇨🇳 · Guo-Li Wang🇨🇳

   In this paper, the dilepton electromagnetic decays ${\chi }_{cJ}(1P)\to J/\psi e^{+}{e}^{-}$ and ${\chi }_{cJ}(1P)\to J\psi {\mu }^{+}{\mu }^{-}$, where ${\chi }_{cJ}$ denotes ${\chi }_{c0}$, ${\chi }_{c1}$ and ${\chi }_{c2}$, are calculated systematically in the improved Bethe-Salpeter method. The numerical results of decay widths and the invariant mass distributions of the final lepton pairs are given. The comparison is made with the recently measured experimental data of BESIII. It is shown that for the cases including $e^{+}{e}^{-}$, the gauge invariance is decisive and should be considered carefully. For the processes of ${\chi }_{cJ}(1P)\to J/\psi e^{+}{e}^{-}$, the branching fraction are: $\mathcal{B}[{\chi }_{c0}(1P)\to J/\psi e^{+}{e}^{-}]=1.06_{-0.18}^{+0.16}\times 10^{-4}$, $\mathcal{B}[{\chi }_{c1}(1P)\to J/\psi e^{+}{e}^{-}]=2.88_{-0.53}^{+0.50}\times 10^{-3}$, and $\mathcal{B}[{\chi }_{c2}(1P)\to J/\psi e^{+}{e}^{-}]=1.74_{-0.21}^{+0.22}\times 10^{-3}$. The calculated branching fractions of ${\chi }_{cJ}(1P)\to J/\psi {\mu }^{+}{\mu }^{-}$ channels are: $\mathcal{B}[{\chi }_{c0}(1P)\to J/\psi {\mu }^{+}{\mu }^{-}]=3.80_{-0.64}^{+0.59}\times 10^{-6}$, $\mathcal{B}[{\chi }_{c1}(1P)\to J/\psi {\mu }^{+}{\mu }^{-}]=2.04_{-0.38}^{+0.36}\times 10^{-4}$, and $\mathcal{B}[{\chi }_{c2}(1P)\to J/\psi {\mu }^{+}{\mu }^{-}]=1.66_{-0.19}^{+0.19}\times 10^{-4}$.

   hep-phEPJC(2019)·6 citations
8. 08*

   Fate of false vacuum in singlet-doublet fermion extension model with RG improved effective action

   Yu Cheng🇨🇳 · Wei Liao🇨🇳

   We study the effective potential and the Renormalization Group(RG) improvement to the effective potential of Higgs boson in a singlet-doublet fermion dark matter extension of the Standard Model(SM), and in general singlet-doublet fermion extension models with several copies of doublet fermions or singlet fermions. We study the stability of the electroweak vacuum with the RG improved effective potential in these models beyond the SM. We study the decay of the electroweak vacuum using the RG improved effective potential in these models beyond the SM. In this study we consider the quantum correction to the kinetic term in the effective action and consider the RG improvement of the kinetic term. Combining all these effects, we find that the decay rate of the false vacuum is slightly changed when calculated using the RG improved effective action in the singlet-doublet fermion dark matter model. In general singlet-doublet fermion extension models, we find that the presence of several copies of doublet fermions can make the electroweak vacuum stable if the new Yukawa couplings are not large. If the new Yukawa couplings are large, the electroweak vacuum can be turned into metastable or unstable again by the presence of extra fermions.

   hep-phPRD(2020)·4 citations
9. 09*

   About The Polarized $\tau$ Lepton Radiative Decay

   G.I. Gakh🇺🇦 · M.I. Konchatnij🇺🇦 · N.P. Merenkov🇺🇦

   The polarization effects in the one-meson radiative decay of the polarized $\tau$ lepton, ${\tau }^{-}\to {\pi }^{-}\gamma {\nu }_{\tau }$, have been investigated. We present the analytical results for the $t-$distribution of the partial differential widths, which responsible for different polarization phenomena, in the case of the photon energy cut: $\omega >X$. These quantities depend on the invariant mass squared $t$ of the pseudoscalar meson and photon and the photon energy cut $X.$ Our analytical formulae, in terms of the weak vector and axial-vector form factors, describing the structure-dependent part of the decay amplitude, are valid also for the decay ${\tau }^{\pm }\to K^{\pm }{\nu }_{\tau }\gamma$ after trivial substitutions of the corresponding constants. We demonstrate the essential decrease of the inner bremsstrahlung contribution in comparison with the structural one with increase of the photon cut energy. In numerical calculations the vector and axial-vector form factors are determined using the chiral effective theory with resonances (R$\chi$T).

   hep-phInt.J.Mod.Phys.A(2019)·0 citations
10. 10*

    Charged Higgs Discovery Prospects

    Baradhwaj Coleppa🇮🇳 · Agnivo Sarkar🇮🇳 · Santosh Kumar Rai🇮🇳

    We study the discovery prospects of the charged Higgs boson in the context of multi Higgs models in certain BSM scenarios. We classify models into three categories based on the charged Higgs coupling properties: gaugophobic, fermiophobic, and chromophobic. In each case, we identify viable modes of discovery, and present LHC analysis for discovery. We find that extensions of the Standard Model in which the charged Higgs does not couple to colored particles offer the best possible avenues for discovery.

    hep-phPRD(2020)·12 citations
11. 11*

    Interference effects in semileptonic decays from heavy Majorana neutrinos

    X. Marcano🇫🇷 · A. Abada🇫🇷 · C. Hati🇫🇷 · A. M. Teixeira🇫🇷

    Several beyond the Standard Model scenarios introduce new heavy neutrinos, whose Dirac or Majorana nature could be tested by comparing the rates of lepton number violating and lepton number conserving processes: a Dirac fermion induces only the latter, while a Majorana one predicts the same rate for both of them. Nevertheless, in the presence of more than one Majorana fermion, this picture may change drastically due to interference effects. We focus on lepton number violating and lepton flavour violating semileptonic meson decays induced by two heavy Majorana fermions, exploring the necessary conditions to have sizeable interference effects and discussing their implications for current experimental constraints and possible future observations. In particular, we show how the $CP$ violating phases may lead to an enhancement of the lepton number violating modes and suppression of the lepton number conserving ones, and vice-versa.

    hep-phPoS(2020)·0 citations
12. 12*

    Unpolarized and spin-dependent DIS structure functions in Double-Logarithmic Approximation

    B.I. Ermolaev🇷🇺 · S.I. Troyan🇷🇺

    We demonstrate how to calculate perturbative components of the structure functions F_1 (for unpolarized DIS) and g_1 (spin-dependent DIS) in Double-Logarithmic Approximation, studying separately the cases of fixed and running QCD coupling. We show that as long as only ladder graphs are accounted for (throughout the talk we use the Feynman gauge for virtual gluons) there is no difference at all between F_1 and g_1. However, accounting for contributions of non-ladder graphs brings an essential difference between them. Applying the Saddle-Point method to the obtained expressions for F_1 and g_1 allows us to arrive at their small-x asymptotics. The both asymptotics are of the Regge kind but with different intercepts. The intercept of F_1 proved to be greater than unity, so it is a new contribution to Pomeron. Finally, we discuss the applicability region of the Regge asymptotics and demonstrate that inappropriate replacement of F_1 and g_1 by their asymptotics outside the applicability region can lead to introducing phenomenological Pomerons for both unploarized and spin-dependent processes.

    hep-phhep-exJ.Phys.Conf.Ser.(2020)·0 citations
13. 13*

    Baseline study for net-proton number fluctuations at top energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider with the Angantyr model

    Nirbhay Kumar Behera🇰🇷 · Ranjit Kumar Nayak🇮🇳 · Sadhana Dash🇮🇳

    The multiplicity percentile dependence of cumulants, of net-proton number distributions in Au$-$Au collisions at $\sqrt{s_{NN}}=$ 200 GeV and Pb$-$Pb collisions at $\sqrt{s_{NN}}=$ 2.76 TeV has been investigated using the Angantyr model (the heavy-ion extension of the \textsc{Pythia 8} model). The effects of finite transverse momentum ($p_{\mathrm{T}}$) and pseudorapidity ($\eta$) acceptance on the net-proton cumulants have also been studied. Furthermore, the effects of the hydrodynamic expansion and feed down from weak decays were explored. It was found that radial flow has substantial impact on the cumulants and their ratios, while weak decays have a finite but relatively smaller effect. The obtained values of cumulants and their ratios with the Angantyr model, where the formation of thermalized medium is not assumed can serve as a baseline for future measurements.

    hep-phhep-exnucl-exPRC(2020)·3 citations
14. 14*

    Scalar triplet leptogenesis in the presence of right-handed neutrinos with S3 symmetry

    Subhasmita Mishra🇮🇳 · Anjan Giri🇮🇳

    Leptogenesis appears to be a viable alternative to account for the baryon asymmetry of the universe through baryogenesis. In this context, we consider a scenario in which the standard model is extended with $S_3$ and $Z_2$ symmetry in addition to the two scalar triplets, two scalar doublets and three right handed neutrinos. Presence of scalar triplets and right-handed neutrinos in the scenarios of both type-I and type-II seesaw framework provide a different leptogenesis option and can help us to understand the matter-antimatter asymmetry with simple $S_3$ symmetry. We discuss the neutrino phenomenology and leptogenesis in both high ($O(10^{10})$ GeV) and low energy scale ($O$(2)TeV) by constraining the Yukawa couplings. Moreover, we also consider the constraints on model parameters from neutrino oscillation data and leptogenesis to explain the rare lepton flavor violating decay and muon g-2 anomaly.

    hep-phJ.Phys.G(2020)·7 citations
15. 15*

    Probing the evolution of heavy-ion collisions using direct photon interferometry

    Oscar Garcia-Montero🇩🇪 · Nicole Löher🇩🇪 · Aleksas Mazeliauskas🇨🇭 · Jürgen Berges🇩🇪 · Klaus Reygers🇩🇪

    We investigate the measurement of Hanbury Brown-Twiss (HBT) photon correlations as an experimental tool to discriminate different sources of photon enhancement, which are proposed to simultaneously reproduce the direct photon yield and the azimuthal anisotropy measured in nuclear collisions at RHIC and the LHC. To showcase this, we consider two different scenarios in which we enhance the yields from standard hydrodynamical simulations. In the first, additional photons are produced from the early pre-equilibrium stage computed from the \textit{bottom-up} thermalization scenario. In the second, the thermal rates are enhanced close to the pseudo-critical temperature $T_c\approx 155\text{MeV}$ using a phenomenological ansatz. We compute the correlators for relative momenta $q_o,q_s$ and $q_l$ for different transverse pair momenta, $K_{\perp }$, and find that the longitudinal correlation is the most sensitive to different photon sources. Our results also demonstrate that including anisotropic pre-equilibrium rates enhances non-Gaussianities in the correlators, which can be quantified using the kurtosis of the correlators. Finally, we study the feasibility of measuring a direct photon HBT signal in the upcoming high-luminosity LHC runs. Considering only statistical uncertainties, we find that with the projected $\sim 10^{10}$ heavy ion events a measurement of the HBT correlations for $K_{\perp }<1\text{GeV}$ is statistically significant.

    hep-phnucl-exnucl-thPRC(2020)·24 citations
16. 16*

    Unitary vs pseudo-unitary time evolution and statistical effects in the dynamical Sauter-Schwinger process

    K. Krajewska🇵🇱 · J. Z. Kamiński🇵🇱

    Dynamical Sauter-Schwinger mechanism of pair creation by a time-dependent electric field comprising of $N_{\mathrm{rep}}$ identical pulses is analyzed within the framework of the spinor and scalar quantum electrodynamics. For linearly polarized pulses, both theories predict that a single eigenmode of the matter wave follows the dynamics of a two-level system. This dynamics, however, is either governed by a Hermitian (for spin 1/2 particles) or pseudo-Hermitian (for spin 0 particles) Hamiltonian. Essentially, both theories lead to a Fraunhofer-type enhancement of the momentum distributions of created pairs. While in the fermionic case the enhancement is never perfect and it deteriorates with increasing the number of pulses in a train $N_{\mathrm{rep}}$, in the bosonic case we observe the opposite. More specifically, it is at exceptional points where the spectra of bosonic pairs scale exactly as $N_{\mathrm{rep}}^2$, and this scaling is even enhanced with increasing the number of pulses in a train.

    hep-phphysics.atom-phPRA(2019)·10 citations
17. 17*

    Non-equilibrium photons from the bottom-up thermalization scenario

    Oscar Garcia-Montero🇩🇪

    In this work, I calculate the $p_{\perp }$ resolved spectra for the three stages of the \textit{bottom-up} scenario, which are comparable to the thermal contribution, particularly at higher values of the saturation scale $Q_S^2$. Analytical solutions are obtained by including a parametrization of scaling solutions from far-from-equilibrium classical statistical lattice simulations into a small angle kinetic rate. Furthermore, a theoretically motivated ansatz is used to account for near-collinear enhancement of the low-$p_{\perp }$ radiation. The system is phenomenologically constrained using the charge hadron multiplicities from LHC and RHIC as in previous parametric estimates and fair agreement with the data available for photons was found. I find that for this realistic set of parameters, the contribution from the thermalizing glasma dominates the excess photons.

    hep-phnucl-exnucl-thAnnals Phys.(2022)·21 citations
18. 18*

    Multilepton signatures for scalar dark matter searches in coannihilation scenario

    Sreemanti Chakraborti🇮🇳 · Rashidul Islam🇮🇳

    We revisit the scalar singlet dark matter (DM) scenario with a pair of dark lepton partners which form a vectorlike Dirac fermionic doublet. The extra doublet couples with the Standard Model (SM) leptonic doublet and the scalar singlet via a non-SM-like Yukawa structure. As a result, (i) since the extra fermionic states interact with other dark sector particles as well as the SM via gauge and Yukawa interactions, it gives rise to new DM annihilation processes including pair annihilation as well as coannihilation channels, and (ii) such a Yukawa structure opens up new production channels for leptonic final states giving much enhancement in cross sections to search for dark matter in the LHC. Using suitable kinematic observables, we train a {\em boosted decision tree} (BDT) classifier to separate enhanced but still feeble light leptonic signals from the background in an effective manner. On the other hand, the same technique is applied to study $\tau$-tagged jets in the search for DM signals.

    hep-phPRD(2020)·2 citations
19. 19*

    Affleck-Dine inflation

    James M. Cline🇨🇦 · Matteo Puel🇨🇦 · Takashi Toma🇨🇦

    The Affleck-Dine mechanism in its simplest form provides baryogenesis from the out-of-equilibrium evolution of a complex scalar field with a simple renormalizable potential. We show that such a model, supplemented by nonminimal coupling to gravity, can also provide inflation, consistent with Planck constraints, simultaneously with the generation of the baryon asymmetry. The predictions of the model include significant tensor-to-scalar ratio and possibly baryon isocurvature fluctuations. The reheating temperature is calculable, making the model fully predictive. We require color triplet scalars for reheating and transfering the primordial baryon asymmetry to quarks; these could be observable at colliders. They can also be probed at higher scales by searches for quark compositeness in dijet angular distributions, and flavor-changing neutral current effects.

    hep-phastro-ph.COPRD(2020)·49 citations
20. 20*

    $D$-wave effects in diffractive electroproduction of heavy quarkonia from the photon-like $V\to Q\bar{Q}$ transition

    Michal Krelina🇨🇱 · Jan Nemchik🇨🇿 · Roman Pasechnik🇸🇪

    We analyze the validity of a commonly used identification between structures of the virtual photon ${\gamma }^{\ast }\to Q\bar{Q}$ and vector meson $V\to Q\bar{Q}$ transitions. In the existing studies of $S$-wave vector-meson photoproduction in the literature, such an identification is typically performed in the light-front (LF) frame while the radial component of the meson wave function is rather postulated than computed from the first principles. The massive photon-like $V\to Q\bar{Q}$ vertex, besides the $S$-wave component, also contains an extra $D$-wave admixture in the $Q\bar{Q}$ rest frame. However, the relative weight of these contributions cannot be justified by any reasonable nonrelativistic $Q\bar{Q}$ potential model. In this work, we investigate the relative role of the $D$-wave contribution starting from the photon-like quarkonium $V\to Q\bar{Q}$ transition in both frames: in the $Q\bar{Q}$ rest frame (with subsequent Melosh spin transform to the LF frame) and in the LF frame (without Melosh transform). We show that the photon-like transition imposed in the $Q\bar{Q}$ rest frame leads to significant discrepancies with the experimental data. In the second case we find that the corresponding total $J/\psi (1S)$ photoproduction cross sections are very close to those obtained with the "$S$-wave only" $V\to Q\bar{Q}$ transition, both leading to a good description of the data. However, we find that the "$S$-wave only" transition leads to a better description of photoproduction data for excited heavy quarkonium states, which represent a more effective tool for study of $D$-wave effects. Consequently, the predictions for production of excited states based on the photon-like structure of $V\to Q\bar{Q}$ transition should be treated with a great care due to a much stronger sensitivity of the $D$-wave contribution to the nodal structure of quarkonium wave functions.

    hep-phnucl-thEPJC(2020)·18 citations
21. 21*

    One-loop electromagnetic correlators of SQED in power-law inflation

    Dražen Glavan🇧🇪 · Gerasimos Rigopoulos🇬🇧

    We examine scalar quantum electrodynamics in power-law inflation space-time, and compute the one-loop correction to electric and magnetic field correlators at superhorizon separations. The effect at one-loop descends from the coupling of the vector to the charged scalar current which is greatly enhanced due to gravitational particle production. We conclude that non-perturbative effects must exist due to (i) secular growth, (ii) spatial running, and (iii) infrared sensitivity of the one-loop correction to the correlators. Electric and magnetic correlators exhibit a hierarchy that is due to Faraday's law and accelerated expansion, and must hold non-perturbatively.

    ↳ gr-qcastro-ph.COhep-phJCAP(2021)·15 citations
22. 22*

    The VHE SED modelling of Markarian 501 in 2009

    Sarira Sahu · Carlos E. Lopez Fortin · Miguel E. Iglesias Martinez · Shigehiro Nagataki · Pedro Fernandez de Cordoba

    The high energy blazar, Markarian 501 was observed as a part of multi-instrument and multiwavelength campaign spanning the whole electromagnetic spectrum for 4.5 months during March 15 to August 1, 2009. On May 1, Whipple 10m telescope observed a very strong $\gamma$-ray flare in a time interval of about 0.5 h. Apart from this flare, high state and low state emissions were also observed by Whipple, VERITAS and MAGIC telescopes. Using the photohadronic model and accounting for the absorption of the extragalactic background light (EBL) to these very high energy $\gamma$-rays, excellent fits are obtained for the observed spectra. We have shown that the intrinsic spectrum for low state emission is flat, however, for high and very high states this is a power-law with slowly increasing exponent.

    ↳ astro-ph.HEhep-phMNRAS(2020)·15 citations
23. 23*

    The ANL-Osaka Partial-Wave Amplitudes of $\pi N$ and $\gamma N$ Reactions

    H. Kamano🇯🇵 · T.-S. H. Lee🇺🇸 · S.X. Nakamura🇨🇳 · T. Sato🇯🇵

    The determination of the Argonne National Laboratory-Osaka University (ANL-Osaka) Partial-Wave Amplitudes (PWA) of $\pi N$ and $\gamma N$ Reactions is reviewed. The predicted PWA are presented on a web page (https://www.phy.anl.gov/theory/research/anl-osaka-pwa). The formulas are given for using the predicted PWA to calculate the cross sections of (1) meson-baryon ($MB$) scattering $MB\to M^{\prime }{B}^{\prime }$ with $MB,M^{\prime }{B}^{\prime }=\pi N,\eta N,K\Lambda ,K\Sigma$, (2) two-pion production $\pi N\to \pi \Delta ,\rho N,\sigma N\to \pi \pi N$, (3) Meson photoproduction $\gamma N\to \pi N,\eta N,K\Lambda ,K\Sigma$, (4) Pion electroproduction $N(e,e^{\prime }\pi )N$, (5) inclusive $N(e,e^{\prime })X$. We also present sample results from our fits to the data.

    ↳ nucl-thhep-exhep-phnucl-ex23 citations
24. 24*

    Implications of the fermion vacuum term in the extended SU(3) Quark Meson model on compact stars properties

    Andreas Zacchi🇩🇪 · Juergen Schaffner-Bielich🇩🇪

    We study the impact of the fermion vacuum term in the SU(3) quark meson model on the equation of state and determine the vacuum parameters for various sigma meson masses. We examine its influence on the equation of state and on the resulting mass radius relations for compact stars. The tidal deformability $\Lambda$ of the stars is studied and compared to the results of the mean field approximation. Parameter sets which fulfill the tidal deformability bounds of GW170817 together with the observed two solar mass limit turn out to be restricted to a quite small parameter range in the mean field approximation. The extended version of the model does not yield solutions fulfilling both constraints. Furthermore, no first order chiral phase transition is found in the extended version of the model, not allowing for the twin star solutions found in the mean field approximation.

    ↳ nucl-thastro-ph.HEhep-phPRD(2019)·21 citations
25. 25*

    Renormalons in integrable field theories

    Marcos Marino🇨🇭 · Tomas Reis🇨🇭

    In integrable field theories in two dimensions, the Bethe ansatz can be used to compute exactly the ground state energy in the presence of an external field coupled to a conserved charge. We generalize previous results by Volin and we extract analytic results for the perturbative expansion of this observable, up to very high order, in various asymptotically free theories: the non-linear sigma model and its supersymmetric extension, the Gross--Neveu model, and the principal chiral field. We study the large order behavior of these perturbative series and we give strong evidence that, as expected, it is controlled by renormalons. Our analysis is sensitive to the next-to-leading correction to the asymptotics, which involves the first two coefficients of the beta function.

    ↳ hep-thhep-phmath-phmath.MPJHEP(2020)·60 citations
26. 26*

    Spectral dimension as a tool for analyzing non-perturbative propagators

    Wolfgang Kern🇦🇹 · Markus Q. Huber🇩🇪 · Reinhard Alkofer🇦🇹

    We derive general properties of the scale-dependent effective spectral dimensions of non-perturbative gauge boson propagators as they appear as solutions from different methods in Yang-Mills theories. In the ultraviolet and for short time scales the anomalous dimensions of the propagators lead to a slight decrease of the spectral dimension as compared to the one of a free propagator. Lowering the momentum scale, the spectral dimension decreases further. The class of propagators which display a maximum at Euclidean momenta, and thus violate positivity, always approaches a spectral dimension of one for large times. We also show that the longest time intervals are not related to the deep infrared but to the momentum scale defined by the position of the maximum.

    ↳ hep-thhep-phPRD(2019)·10 citations
27. 27*

    Catching a glimpse of the parton structure of the bound proton

    Sara Fucini🇮🇹 · Sergio Scopetta🇮🇹 · Michele Viviani🇮🇹

    A new generation of experiments is expected to shed light on the elusive parton structure of the bound proton. One of the most promising directions is incoherent deeply virtual Compton scattering, which can provide a tomographic view of the bound proton. The first measurement has been recently performed, using ${}^4$He targets at Jefferson Lab. In the work presented here, a rigorous Impulse Approximation analysis of this process is proposed. As ingredients, state-of-the-art models of the nuclear spectral function and of the parton structure of the struck proton, together with novel scattering amplitudes expressions for a bound moving nucleon, have been used. A good overall agreement with the data is obtained, in particular at high values of the photon virtuality. The observed big difference between results for the bound proton and those for the free one turns out to be due in small part to modifications of the parton structure, and rather it should be related to kinematical nuclear effects. The analysis demonstrates that the comparison of the results of this approach, based on a conventional description, with future precise data, has the potential to expose exotic quark and gluon effects in nuclei.

    ↳ nucl-thhep-phnucl-exPRD(2020)·12 citations
28. 28*

    Interaction networks for the identification of boosted $H\to b\overline{b}$ decays

    Eric A. Moreno🇺🇸 · Thong Q. Nguyen🇺🇸 · Jean-Roch Vlimant🇺🇸 · Olmo Cerri🇺🇸 · Harvey B. Newman🇺🇸 · Avikar Periwal🇺🇸 · Maria Spiropulu🇺🇸 · Javier M. Duarte🇺🇸 · Maurizio Pierini🇨🇭

    We develop an algorithm based on an interaction network to identify high-transverse-momentum Higgs bosons decaying to bottom quark-antiquark pairs and distinguish them from ordinary jets that reflect the configurations of quarks and gluons at short distances. The algorithm's inputs are features of the reconstructed charged particles in a jet and the secondary vertices associated with them. Describing the jet shower as a combination of particle-to-particle and particle-to-vertex interactions, the model is trained to learn a jet representation on which the classification problem is optimized. The algorithm is trained on simulated samples of realistic LHC collisions, released by the CMS Collaboration on the CERN Open Data Portal. The interaction network achieves a drastic improvement in the identification performance with respect to state-of-the-art algorithms.

    ↳ hep-exhep-phPRD(2020)·93 citations

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