Tue·Dec 18, 2018Tuesday·December 18, 2018

1. 01*

   Common origin of baryon asymmetry, dark matter and neutrino mass

   Anirban Biswas🇮🇳 · Sandhya Choubey🇮🇳 · Laura Covi🇩🇪 · Sarif Khan🇮🇳

   In this work, we explain three beyond standard model (BSM) phenomena, namely neutrino masses, the baryon asymmetry of the Universe and Dark Matter, within a single model and in each explanation the right handed (RH) neutrinos play the prime role. Indeed by just introducing two RH neutrinos we can generate the neutrino masses by the Type-I seesaw mechanism. The baryon asymmetry of the Universe can arise from thermal leptogenesis from the decay of lightest RH neutrino before the decoupling of the electroweak sphaleron transitions, which redistribute the $B-L$ number into a baryon number. At the same time, the decay of the RH neutrino can produce the Dark Matter (DM) as an asymmetric Dark Matter component. The source of CP violation in the two sectors is exactly the same, related to the complex couplings of the neutrinos. By determining the comoving number density for different values of the CP violation in the DM sector, we obtain a particular value of the DM mass after satisfying the relic density bound. We also give prediction for the DM direct detection (DD) in the near future by different ongoing DD experiments.

   hep-phJHEP(2019)·22 citations
2. 02*

   Mechanical properties of particles

   Maxim V. Polyakov🇷🇺 · Peter Schweitzer🇺🇸

   Selected topics related to the physics of the energy-momentum tensor (EMT) form factors are discussed. The topics are: 1) Fundamental mechanical properties of particles and gravity 2) Mechanical properties of non-spherical particles 3) Gravitational form factors of Goldstone bosons 4) Nucleon's seismology?

   hep-phhep-exnucl-exPoS(2019)·32 citations
3. 03*

   Extraction of the CKM phase $\gamma$ using charmless 3-body decays of $B$ mesons

   Emilie Bertholet🇫🇷 · Eli Ben-Haim🇫🇷 · Bhubanjyoti Bhattacharya🇺🇸 · Matthew Charles🇫🇷 · David London🇨🇦

   The weak phase $\gamma$ is extracted from three-body charmless decays of $B$ mesons following a method proposed by Bhattacharya, Imbeault \& London. The result is obtained by combining the BABAR amplitude analyses for the processes $B^0\to K^{+}{\pi }^0{\pi }^{-}$, $B^0\to K_S^0{\pi }^{+}{\pi }^{-}$, $B^0\to K_S^0{K}_S^0{K}_S^0$, $B^0\to K^{+}{K}_S^0{K}^{-}$ and $B^{+}\to K^{+}{\pi }^{+}{\pi }^{-}$, under the assumption of ${\alpha }_{\mathrm{SU}(3)}$ flavour symmetry. Six possible solutions are found. One solution is compatible with the Standard Model while the others are not. It is also found that, when averaged over the entire Dalitz plane, the effect of ${\alpha }_{\mathrm{SU}(3)}$ breaking on the analysis is only at the percent level.

   hep-phhep-exPRD(2019)·13 citations
4. 04*

   Pions near condensation under compact star conditions

   Cristian Villavicencio🇨🇱 · Marcelo Loewe🇨🇱 · Alfredo Raya🇲🇽

   The behavior of pions is studied in systems where their normal leptonic decay is forbidden. When thermal fluctuations are present, a low decay rate is generated, and as a consequence of lepton recombination, the amount of pions remains almost unaltered. Compact stars conditions are favorable for the formation of such intermediate state of charged pions: near condensation and almost stable, leading to a continuum source of anti-neutrinos. In particular, protoneutron stars could be an scenario where this state of matter is relevant.

   hep-phastro-ph.HEnucl-thAstron.Nachr.(2019)·0 citations
5. 05*

   Electroweak phase transition and Higgs phenomenology in the Georgi-Machacek model

   Ruiyu Zhou🇨🇳 · Wei Cheng🇨🇳 · Xin Deng🇨🇳 · Ligong Bian🇨🇳 · Yongcheng Wu🇨🇦

   In this work, we perform the electroweak phase transition study with the Georgi-Machacek model. We investigate both the one-step and two-step strong first order electroweak phase transition (SFOEWPT). The SFOEWPT viable parameter spaces could be tested by the future 14 TeV LHC, HL-LHC, and ILC. The LHC Higgs signal strength measurements severely bound the SFOEWPT valid parameter spaces, a tinny region of the mixing angle between the neutral fields of the isospin-doublet and isospin-triplet scalars around $\alpha \sim 0$ can allow the two-step SFOEWPT to occur. The triplet vacuum expectation value (VEV) is crucial for both SFOEWPT and related Higgs phenomenology. The two-step SFOEWPT can be distinguished from the one-step SFOEWPT through the triple Higgs coupling searches and the low mass doubly charged Higgs searches at colliders.

   hep-phJHEP(2019)·47 citations
6. 06*

   Centrality dependence of deuteron production in Pb+Pb collisions at 2.76 TeV via hydrodynamics and hadronic afterburner

   Dmytro Oliinychenko🇺🇸 · Long-Gang Pang🇺🇸 · Hannah Elfner🇩🇪 · Volker Koch🇺🇸

   The deuteron binding energy is only 2.2 MeV. At the same time, its yield in Pb+Pb collisions at $\sqrt{s_{NN}}=$2.76 TeV corresponds to a thermal yield at the temperature around 155 MeV, which is too hot to keep deuterons bound. This puzzle is not completely resolved yet. In general, the mechanism of light nuclei production in ultra-high energy heavy ion collisions remains under debate. In a previous work [1] we suggest a microscopic explanation of the deuteron production in central ultra-relativistic Pb+Pb collisions, the main mechanism being $\pi pn\leftrightarrow \pi d$ reactions in the hadronic phase of the collision. We use a state-of-the-art hybrid approach, combining relativistic hydrodynamics for the hot and dense stage and hadronic transport for a later, more dilute stage. Deuteron rescattering in the hadronic stage is implemented explicitly, using its experimentally measured vacuum cross-sections. In these proceedings we extend our previous work to non-central collisions, keeping exactly the same methodology and parameters. We find that our approach leads to a good description of the measured deuteron transverse momentum spectra at centralities up to 40%, and underestimates the amount of deuterons at low transverse momentum at higher centralities. Nevertheless, the coalescence parameter $B_2$, measured by ALICE collaboration, is reproduced well in our approach even for peripheral collisions.

   hep-phnucl-thMDPI Proc.(2019)·13 citations
7. 07*

   A Gauged Flavor Model of Quarks and Leptons

   Bradley L. Rachlin🇺🇸 · Thomas W. Kephart🇺🇸

   Beyond Standard Model physics frequently connects flavor symmetry with a discrete group. If the discrete symmetry arises spontaneously from a gauge theory, one can maintain compatibility with quantum gravity and avoid anomalies. We provide an example of such a model with the Standard Model gauge group extended to $SU(3{)}_C\times SU(2{)}_L\times U(1{)}_Y\times SU(2{)}_{T^{\prime }}$ where the binary tetrahedral flavor group $T^{\prime }$ is embedded in $SU(2{)}_{T^{\prime }}$. Quark and lepton masses and mixing angles are fit to data, where lepton mixing angles are shifted from tribimaximal values by the addition of scalar VEVs to agree with the experimental data.

   hep-ph2 citations
8. 08*

   Eta-nucleon and eta-prime-nucleon coupling constants in QCD and the role of gluons

   Janardan P. Singh🇮🇳 · Shesha D. Patel🇮🇳

   Coupling constants of $\eta$ and ${\eta }^{\prime }$ mesons with nucleons have been calculated using the method of QCD sum rules. Starting from vacuum-to-meson correlation function of interpolating fields of two nucleons, its matrix element with respect to nucleon spinors has been considered. Coupling constants at the physical points have been estimated from extrapolation of results obtained at two other points. Anomalous glue has been found to give substantial contribution to the coupling constants and also accounts for a significant OZI-rule violation.

   hep-phPLB(2019)·9 citations
9. 09*

   Effective Field Theory and Lattice QCD approaches for hard probes in QCD matter

   Miguel Ángel Escobedo🇫🇮

   Hard Probes are an essential tool to discover the properties of the quark-gluon plasma created in heavy-ion collisions. The study of hard probes always involves taking into account very different energy scales, and this is precisely the situation in which Effective Fields Theories (EFTs) are useful. EFTs can be used to separate the short-distance and perturbative physics from the long-distance and non-perturbative. This method combined with Lattice QCD evaluations of the long-distance effects can provide accurate and first principles results. In this proceeding, I will report recent advances in this direction. Results from an EFT computation of quarkonium $R_{AA}$ at $\sqrt{s_{NN}}=5.02\text{TeV}$ are shown for the first time here.

   hep-phPoS(2018)·1 citation
10. 10*

    One-loop Dirac neutrino mass and mixed axion/WIMP dark matter

    Cristian D. R. Carvajal🇨🇴 · Óscar Zapata🇨🇴

    We consider the Peccei-Quinn (PQ) mechanism as the one behind the Dirac neutrino masses when these are generated through the $d=5$ effective operator $\bar{L}\tilde{H}{N}_R\varphi$ at one loop level, with $\varphi$ being a Standard Model singlet scalar. In this setup, the PQ symmetry guarantees that the one-loop realization of such an effective operator gives the leading contribution to the Dirac neutrino masses by forbidding the contributions arising from its tree level realizations. All the mediators in the one-loop neutrino mass diagrams can be stabilized by a remnant $Z_N$ symmetry from the PQ symmetry breaking, thus forming a dark sector besides the axion sector and leading to mixed axion/WIMP dark matter scenarios.

    hep-phPRD(2019)·32 citations
11. 11*

    Pole mass determination in presence of heavy particles

    Henning Bahl🇩🇪

    We investigate the determination of the Higgs-boson propagator poles in the MSSM. Based upon earlier works, we point out that in case of a large hierarchy between the electroweak scale and one or more SUSY masses a numerical determination with $\overline{\text{DR}}$ Higgs field renormalization induces higher order terms which would cancel in a more complete calculation. The origin of these terms is the momentum dependence of contributions involving at least one of the heavy particles. We present two different methods to avoid their appearance. In the first approach, the poles are determined by expanding around the one-loop solutions. In the second approach, a "heavy-OS" Higgs field renormalization is employed in order to absorb the momentum dependence of heavy contributions. We will find that the first approach leads to an unwanted behaviour of the Higgs boson mass predictions close to crossing points where two Higgs bosons that mix with each other are almost mass degenerate. These problems are avoided in the second approach, which became the default approach used in the public code FeynHiggs. Despite the discussion being very specific to the MSSM, the argumentation and the methods presented in this work are straightforwardly applicable to the determination of propagator poles in other models involving a large mass hierarchy.

    hep-phJHEP(2019)·25 citations
12. 12*

    $\tau \to {\nu }_{\tau }{\rho }^0{\pi }^{-}$ decay in the Nambu - Jona-Lasinio model

    A. A. Osipov🇷🇺

    Within the context of an extended Nambu - Jona-Lasinio model, we analyze the role of the axial-vector $a_1(1260)$ and $a_1(1640)$ mesons in the decay $\tau \to {\nu }_{\tau }{\rho }^0{\pi }^{-}$. The contributions of pseudoscalar $\pi$ and $\pi (1300)$ states are also considered. The form factors for the decay amplitude are determined in terms of the masses and widths of these states. To describe the radial excited states $\pi (1300)$ and $a_1(1640)$ we introduce two additional parameters which can be estimated theoretically, or fixed from experiment. The decay rate and $\rho \pi$ mass spectrum are calculated.

    hep-phPRD(2019)·3 citations
13. 13*

    A Mini-review on Vector-like Leptonic Dark Matter, Neutrino Mass and Collider Signatures

    Subhaditya Bhattacharya🇮🇳 · Purusottam Ghosh🇮🇳 · Nirakar Sahoo🇮🇳 · Narendra Sahu🇮🇳

    We review a class of models in which the Standard Model (SM) is augmented by vector-like leptons: one doublet and a singlet, which are odd under an unbroken discrete $Z_2$ symmetry. As a result, the neutral component of these additional vector-like leptons are stable and behave as dark matter. We study the phenomenological constraints on the model parameters and elucidate the parameter space for relic density, direct detection and collider signatures of dark matter. In such models, we further add a scalar triplet of hypercharge two and study the consequences. In particular, after electro weak symmetry breaking (EWSB), the triplet scalar gets an induced vacuum expectation value (vev), which yield Majorana masses not only to the light neutrinos but also to vector-like leptonic doublet DM. Due to the Majorana mass of DM, the $Z$ mediated elastic scattering with nucleon is forbidden and hence allowing the model to survive from stringent direct search bound. The DM without scalar triplet lives in a small singlet-doublet leptonic mixing region ($\sin \theta \le 0.1$) due to large contribution from singlet component and have small mass difference ($\Delta m\sim 10$ GeV) with charged companion, the NLSP (next to lightest stable particle), to aid co-annihilation for yielding correct relic density. Both these observations change to certain extent in presence of scalar triplet to aid observability of hadronically quiet leptonic final states at LHC, while one may also confirm/rule-out the model through displaced vertex signal of NLSP, a characteristic signature of the model in relic density and direct search allowed parameter space.

    hep-phFront.in Phys.(2019)·64 citations
14. 14*

    Precision Determination of ${\alpha }_s$ from Lattice QCD

    Mattia Dalla Brida (on behalf of the ALPHA Collaboration)🇮🇹

    We present an overview of the recent lattice determination of the QCD coupling ${\alpha }_s$ by the ALPHA Collaboration. The computation is based on the non-perturbative determination of the $\Lambda$-parameter of $N_{\mathrm{f}}=3$ QCD, and the perturbative matching of the $N_{\mathrm{f}}=3$ and $N_{\mathrm{f}}=5$ theories. The final result: ${\alpha }_s(m_Z)=0.11852(84)$, reaches sub-percent accuracy.

    hep-phhep-latUniverse(2018)·5 citations
15. 15*

    Impact of the inelastic proton -- nucleus cross section on the prompt neutrino flux

    A. V. Giannini🇧🇷 · V. P. Goncalves🇧🇷

    The description of the inelastic proton -- nucleus cross section at very high energies is still an open question. The current theoretical uncertainty has direct impact on the predictions of the cosmic ray and neutrino physics observables. In this paper we consider different models for the treatment of ${\sigma }_{inel}^{pA}$, compare its predictions at ultrahigh cosmic ray energies and estimate the prompt neutrino flux at the neutrino energies that have been probed by the IceCube Observatory. We demonstrate that depending of the model used to describe ${\sigma }_{inel}^{pA}$, the predictions for the prompt neutrino flux can differ by a factor of order of three. Such result demonstrate the importance of a precise measurement of the inelastic proton -- nucleus cross section at high energies.

    hep-phnucl-thEPJC(2019)·1 citation
16. 16*

    Event generation for beam dump experiments

    Luca Buonocore🇨🇭 · Claudia Frugiuele🇮🇱 · Fabio Maltoni🇧🇪 · Olivier Mattelaer🇧🇪 · Francesco Tramontano🇮🇹

    A wealth of new physics models which are motivated by questions such as the nature of dark matter, the origin of the neutrino masses and the baryon asymmetry in the universe, predict the existence of hidden sectors featuring new particles. Among the possibilities are heavy neutral leptons, vectors and scalars, that feebly interact with the Standard Model (SM) sector and are typically light and long lived. Such new states could be produced in high-intensity facilities, the so-called beam dump experiments, either directly in the hard interaction or as a decay product of heavier mesons. They could then decay back to the SM or to hidden sector particles, giving rise to peculiar decay or interaction signatures in a far-placed detector. Simulating such kind of events presents a challenge, as not only short-distance new physics (hard production, hadron decays, and interaction with the detector) and usual SM phenomena need to be described but also the travel has to be accounted for as determined by the geometry of the detector. In this work, we describe a new plugin to the {\sc MadGraph5\_aMC@NLO} platform, which allows the complete simulation of new physics processes relevant for beam dump experiments, including the various mechanisms for the production of hidden particles, namely their decays or scattering off SM particles, as well as their far detection, keeping into account spatial correlations and the geometry of the experiment.

    hep-phhep-exJHEP(2019)·47 citations
17. 17*

    Future physics opportunities for high-density QCD at the LHC with heavy-ion and proton beams

    Z. Citron🇮🇱 · A. Dainese🇮🇹 · J.F. Grosse-Oetringhaus🇨🇭 · J.M. Jowett🇨🇭 · Y.-J. Lee🇺🇸 · U.A. Wiedemann🇨🇭 · M. Winn (editors)🇫🇷 · A. Andronic🇩🇪 · F. Bellini🇨🇭 · E. Bruna🇮🇹 · E. Chapon🇨🇭 · H. Dembinski🇩🇪 and 173 other authors

    The future opportunities for high-density QCD studies with ion and proton beams at the LHC are presented. Four major scientific goals are identified: the characterisation of the macroscopic long wavelength Quark-Gluon Plasma (QGP) properties with unprecedented precision, the investigation of the microscopic parton dynamics underlying QGP properties, the development of a unified picture of particle production and QCD dynamics from small (pp) to large (nucleus--nucleus) systems, the exploration of parton densities in nuclei in a broad ($x$, $Q^2$) kinematic range and the search for the possible onset of parton saturation. In order to address these scientific goals, high-luminosity Pb-Pb and p-Pb programmes are considered as priorities for Runs 3 and 4, complemented by high-multiplicity studies in pp collisions and a short run with oxygen ions. High-luminosity runs with intermediate-mass nuclei, for example Ar or Kr, are considered as an appealing case for extending the heavy-ion programme at the LHC beyond Run 4. The potential of the High-Energy LHC to probe QCD matter with newly-available observables, at twice larger center-of-mass energies than the LHC, is investigated.

    hep-phhep-exnucl-exnucl-thCERN Yellow Rep.Monogr.(2019)·426 citations
18. 18*

    $J/\psi$ production in hadron scattering: three-pomeron contribution

    Eugene Levin🇮🇱 · Marat Siddikov🇨🇱

    In this paper we discuss the inclusive $J/\psi$ production in proton-proton collisions from fusion of three pomerons. We demonstrate that this mechanism gets dominant contribution from the region which can be theoretically described by CGC/Saturation approach. Numerically, it gives a substantial contribution to the $J/\psi$ production, and is able to describe the experimentally observable shapes of the rapidity, momenta and multiplicity distributions. The latter fact provides a natural explanation of the experimentally observed enhancement of multiplicity distribution in $J/\psi$ production.

    hep-phhep-exEPJC(2019)·21 citations
19. 19*

    Probing Heavy Spin-2 Bosons with $\gamma \gamma$ final states from Vector Boson Fusion Processes at the LHC

    Andrés Flórez🇨🇴 · Yuhan Guo🇺🇸 · Alfredo Gurrola🇺🇸 · Will Johns🇺🇸 · Oishik Ray🇺🇸 · Paul Sheldon🇺🇸 · Savanna Starko🇺🇸

    New massive spin-2 particles are predicted in theoretical extensions to the Standard Model (SM) attempting to solve the hierarchy problem. Such theories postulate that gravity is diluted compared to the other fundamental forces because it can propagate in extra spatial dimensions. While such theoretical models are of high experimental interest because they predict massive spin-2 particles ($Y_2$) potentially detectable by collider experiments, searches at the Large Hadron Collider (LHC) have thus far produced no significant evidence for their existence. This work considers a hypothetical physics scenario where low coupling strengths between the $Y_2$ and quarks/gluons is the underlying reason behind the null $Y_2$ search results at the LHC, which have mainly relied on Drell-Yan and gluon-gluon fusion production mechanisms. The focus of this paper is a feasibility study to search for $Y_2$ particles using vector boson fusion (VBF) processes at the LHC. In the context of an effective field theory approach with varying couplings ${\kappa }_V$ between $Y_2$ and the weak bosons of the SM, we consider the $Y_2\to \gamma \gamma$ decay mode to show that the requirement of a diphoton pair combined with two high $p_T$ forward jets with large dijet mass and with large separation in pseudorapidity can significantly reduce the SM backgrounds. Assuming proton-proton collisions at $\sqrt{s}=13$ TeV, we present the total VBF production cross sections, $Y_2$ decay widths, and $Y_2\to \gamma \gamma$ branching ratios as a function of $m(Y_2)$, considering universal and non-universal couplings to the SM particles. The unitarity-violating phase space is described. The proposed VBF $Y_2\to \gamma \gamma$ search is expected to achieve a discovery reach with signal significance greater than 5$\sigma$ for $Y_2$ masses up to 4.4 TeV and ${\kappa }_V$ couplings down to 0.5.

    hep-phPRD(2019)·17 citations
20. 20*

    Constraints on charmphilic solutions to the muon g-2 with leptoquarks

    Kamila Kowalska🇵🇱 · Enrico Maria Sessolo🇵🇱 · Yasuhiro Yamamoto🇵🇱

    We derive constraints from flavor and LHC searches on charmphilic contributions to the muon anomalous magnetic moment with a single leptoquark. Only the scalar leptoquarks $S_1$ and $R_2$ are relevant for the present analysis. We find that for $S_1$ some parameter space remains consistent at $2\sigma$ with the Brookhaven National Laboratory measurement of the muon $g-2$, under the assumption that the left-type coupling between the muon and the charm quark is a free parameter. The surviving parameter space is, on the other hand, going to be probed in its entirety at the LHC with 300/fb of luminosity or less. All other possibilities are excluded by the LHC dimuon search results in combination with several flavor bounds, which together require one to introduce sizable couplings to the top quark to be evaded.

    hep-phPRD(2019)·39 citations
21. 21*

    High energy scattering and emission in QED&QCD media

    Xabier Feal🇪🇸

    A formalism for the evaluation of the intensity of photon and gluon bremsstrahlung in QED and QCD condensed media is presented which considers general interactions beyond the Fokker-Planck/Gaussian approximation, the angular distribution of the final particles and admits finite or structured target calculations. The Boltzmann/transport approaches of Migdal, Bell and the Baier-Dokshitzer-Mueller-Peigné-Schiff group, and the light-cone path integral formalisms of Zakharov and Wiedemann and Gyulassy are recovered as particular cases within the Fokker-Planck limit, which assumes Brownian motion for the intervening particles. Weinberg's soft photon theorem is shown to saturate the Landau-Pomeranchuk-Migdal supression in the soft photon/gluon regime of vanishing phases. The intensity under realistic screened interactions is larger than the existing Fokker-Planck results by a factor 3-4 and the changes can not be accounted for by a single definition of the medium transport properties through $\hat{q}$. This may also suggest that larger gluon elastic cross sections, leading to the hypothesis of strongly coupled Quark Gluon Plasma, may not be required to match the data.

    hep-phhep-th7 citations
22. 22*

    Helicity Methods for High Multiplicity Subleading Soft and Collinear Limits

    Arindam Bhattacharya🇺🇸 · Ian Moult🇺🇸 · Iain W. Stewart🇺🇸 · Gherardo Vita🇺🇸

    The factorization of multi-leg gauge theory amplitudes in the soft and collinear limits provides strong constraints on the structure of amplitudes, and enables efficient calculations of multi-jet observables at the LHC. There is significant interest in extending this understanding to include subleading powers in the soft and collinear limits. While this has been achieved for low point amplitudes, for higher point functions there is a proliferation of variables and more complicated phase space, making the analysis more challenging. By combining the subleading power expansion of spinor-helicity variables in collinear limits with consistency relations derived from the soft collinear effective theory, we show how to efficiently extract the subleading power leading logarithms of $N$-jet event shape observables directly from known spinor-helicity amplitudes. At subleading power, we observe the presence of power law singularities arising solely from the expansion of the amplitudes, which for hadron collider event shapes lead to the presence of derivatives of parton distributions. The techniques introduced here can be used to efficiently compute the power corrections for $N$-jettiness subtractions for processes involving jets at the LHC.

    hep-phhep-thnucl-thJHEP(2019)·43 citations
23. 23*

    Emerging $\Delta M_d$-Anomaly from Tree-Level Determinations of $|V_{cb}|$ and the Angle $\gamma$

    Monika Blanke🇩🇪 · Andrzej J. Buras🇩🇪

    We point out that the recently increased value of the angle $\gamma$ in the Unitarity Triangle (UT), determined in tree-level decays to be $\gamma =(74.0_{-5.8}^{+5.0}{)}^{\circ }$ by the LHCb collaboration, combined with the most recent value of $|V_{cb}|$ implies an enhancement of $\Delta M_d$ over the data in the ballpark of $30\%$. This is roughly by a factor of two larger than the enhancement of $\Delta M_s$ that is independent of $\gamma$. This disparity of enhancements is problematic for models with Constrained Minimal Flavour Violation (CMFV) and also for $U(2{)}^3$ models. In view of the prospects of measuring $\gamma$ with the precision of $\pm 1^{\circ }$ by Belle II and LHCb in the coming years, we propose to use the angles $\gamma$ and $\beta$ together with $|V_{cb}|$ and $|V_{us}|$ as the fundamental parameters of the CKM matrix until $|V_{ub}|$ from tree-level decays will be known precisely. Displaying $\Delta M_{s,d}$ as functions of $\gamma$ clearly demonstrates the tension between the value of $\gamma$ from tree-level decays, free from new physics (NP) contributions, and $\Delta M_{s,d}$ calculated in CMFV and $U(2{)}^3$ models and thus exhibits the presence of NP contributions to $\Delta M_{s,d}$ beyond these frameworks. We calculate the values of $|V_{ub}|$ and $|V_{td}|$ as functions of $\gamma$ and $|V_{cb}|$ and discuss the implications of our results for ${\epsilon }_K$ and rare $K$ and $B$ decays. We also briefly discuss a future strategy in which $\beta$, possibly affected by NP, is replaced by $|V_{ub}|$.

    hep-phhep-exhep-latEPJC(2019)·39 citations
24. 24*

    Subtracted Cumulants: Mitigating Large Background in Jet Substructure

    Yang-Ting Chien🇺🇸 · Daekyoung Kang🇨🇳 · Kyle Lee🇺🇸 · Yiannis Makris🇺🇸

    We introduce a new approach for jet physics studies using subtracted cumulants of jet substructure observables, which are shown to be insensitive to contributions from soft-particle emissions uncorrelated with the hard process. Therefore subtracted cumulants allow comparisons between theoretical calculations and experimental measurements without the complication of large background contaminations such as underlying and pile-up events in hadron collisions. We test our method using subtracted jet mass cumulants by comparing Monte Carlo simulations to analytic calculations performed using soft-collinear effective theory. We find that, for proton-proton collisions, the method efficiently eliminates contributions from multiparton interactions and pile-up events. We also find within theoretical uncertainty our analytic calculations are in good agreement with the subtracted cumulants calculated by using ATLAS jet mass measurements.

    hep-phhep-exPRD(2019)·6 citations
25. 25*

    Charm-quark Yukawa Coupling in $h\to c\bar{c}\gamma$ at LHC

    Tao Han🇺🇸 · Benjamin Nachman🇺🇸 · Xing Wang🇺🇸

    It is extremely challenging to probe the charm-quark Yukawa coupling at hadron colliders primarily due to the large Standard Model (SM) background (including $h\to b\bar{b}$) and the lack of an effective trigger for the signal $h\to c\bar{c}$. We examine the feasibility of probing this coupling at the LHC via a Higgs radiative decay $h\to c\bar{c}\gamma$. The existence of an additional photon in the final state may help for the signal identification and background suppression. Adopting a refined triggering strategy and utilizing basic machine learning, we find that a coupling limit of about 8 times the SM value may be reached with $2\sigma$ sensitivity after the High Luminosity LHC (HL-LHC). Our result is comparable and complementary to other projections for direct and indirect probes of $h\to c\bar{c}$ at the HL-LHC. Without a significant change in detector capabilities, there would be no significant improvement for this search from higher energy hadron colliders.

    hep-phhep-exPLB(2019)·15 citations
26. 26*

    The Supercooled Universe

    Pietro Baratella🇪🇸 · Alex Pomarol🇪🇸 · Fabrizio Rompineve🇪🇸

    Strongly-coupled theories at the TeV can naturally drive a long period of supercooling in the early universe. Trapped into the deconfined phase, the universe could inflate and cool down till the temperature reaches the QCD strong scale. We show how at these low temperatures QCD effects are important and could trigger the exit from the long supercooling era. We also study the implications on relic abundances. In particular, the latent heat released at the end of supercooling could be the reason for the similarities between dark matter and baryon energy densities. The axion abundance could also be significantly affected, allowing for larger values of the axion decay constant. Finally, we discuss how a long supercooling epoch could lead to an enhanced gravitational wave signal.

    hep-phastro-ph.COJHEP(2019)·159 citations
27. 27*

    Dark matter imprint on ${}^8$B neutrino spectrum

    Ilídio Lopes🇵🇹 · Joseph Silk🇫🇷

    The next generation of solar neutrino detectors will provide a precision measure of the ${}^8$B electron-neutrino spectrum in the energy range from 1-15 MeV. Although the neutrino spectrum emitted by ${}^8$B $\beta$-decay reactions in the Sun's core is identical to the neutrino spectrum measured in the laboratory, due to vacuum and matter flavor oscillations, this spectrum will be very different from that measured on Earth by the different solar neutrino experiments. We study how the presence of dark matter (DM) in the Sun's core changes the shape of the ${}^8$B electron-neutrino spectrum. These modifications are caused by local variations of the electronic density and the ${}^8$B neutrino source, induced by local changes of the temperature, density and chemical composition. Particularly relevant are the shape changes at low and medium energy range $(E_{\nu }\le 10\mathrm{MeV})$, for which the experimental noise level is expected to be quite small. If such a distortion in the ${}^8$B${\nu }_e$ spectrum were to be observed, this would strongly hint in favor of the existence of DM in the Sun's core. The ${}^8$B electron-neutrino spectrum provides a complementary method to helioseismology and total neutrino fluxes for constraining the DM properties. In particular, we study the impact of light asymmetric DM on solar neutrino spectra. Accurate neutrino spectra measurements could help to determine whether light asymmetric DM exists in the Sun's core, since it has been recently advocated that this type of DM might resolve the solar abundance problem.

    hep-phastro-ph.COastro-ph.SRPRD(2019)·15 citations
28. 28*

    Theory and Phenomenology of Two Higgs Doublet Type-II Seesaw Model at the LHC Run-2

    Brahim Ait Ouazghour🇲🇦 · Abdesslam Arhrib🇲🇦 · Rachid Benbrik🇲🇦 · Mohamed Chabab🇲🇦 · Larbi Rahili🇲🇦

    We study the most popular scalar extension of the Standard Model, namely the Two Higgs doublet model, extended by a complex triplet scalar (2HDMcT). Such considering model with a very small vacuum expectation value, provides a solution to the massive neutrinos through the so-called type II seesaw mechanism. We show that the 2HDMcT enlarged parameter space allow for a rich and interesting phenomenology compatible with current experimental constraints. In this paper the 2HDMcT is subject to a detailed scrutiny. Indeed, a complete set of tree level unitarity constraints on the coupling parameters of the potential is determined, and the exact tree-level boundedness from below constraints on these couplings are generated for all directions. We then perform an extensive parameter scan in the 2HDMcT parameter space, delimited by the above derived theoretical constraints as well as by experimental limits. We find that an important triplet admixtures are still compatible with the Higgs data and investigate which observables will allow to restrict the triplet nature most effectively in the next runs of the LHC. Finally, we emphasize new production and decay channels and their phenomenological relevance and treatment at the LHC.

    hep-phPRD(2019)·23 citations
29. 29*

    Jet substructure modification in a QGP from a multi-scale description of jet evolution with JETSCAPE

    Y. Tachibana🇺🇸 · A. Angerami🇺🇸 · S. A. Bass🇺🇸 · S. Cao · J. Coleman🇬🇧 · L. Cunqueiro🇺🇸 · T. Dai🇺🇸 · L. Du🇺🇸 · H. Elfner🇩🇪 · D. Everett🇺🇸 · W. Fan🇺🇸 · R. Fries🇺🇸 and 32 other authors

    The modification of jet substructure in relativistic heavy-ion collisions is studied using JETSCAPE, a publicly available software package containing a framework for Monte Carlo event generators. Multi-stage jet evolution in JETSCAPE provides an integrated description of jet quenching by combining multiple models, with each becoming active at a different stage of the parton shower evolution. Jet substructure modification due to different aspects of jet quenching is studied using jet shape and jet fragmentation observables. Various combinations of jet energy loss models are exploed, with medium background provided by (2 + 1)-D VISHNU with TRENTo+freestreaming initial conditions. Results reported here are from simulations performed within JETSCAPE framework.

    ↳ nucl-thhep-phnucl-exPoS(2018)·17 citations
30. 30*

    Thermodynamics in quenched QCD: energy--momentum tensor with two-loop order coefficients in the gradient flow formalism

    Takumi Iritani🇯🇵 · Masakiyo Kitazawa🇯🇵 · Hiroshi Suzuki🇯🇵 · Hiromasa Takaura🇯🇵

    Recently, Harlander et al.\ [Eur.\ Phys.\ J.\ C {\bf 78}, 944 (2018)] have computed the two-loop order (i.e., NNLO) coefficients in the gradient-flow representation of the energy--momentum tensor (EMT) in vector-like gauge theories. In this paper, we study the effect of the two-loop order corrections (and the three-loop order correction for the trace part of the EMT, which is available through the trace anomaly) on the lattice computation of thermodynamic quantities in quenched QCD. The use of the two-loop order coefficients generally reduces the $t$~dependence of the expectation values of the EMT in the gradient-flow representation, where $t$~is the flow time. With the use of the two-loop order coefficients, therefore, the $t\to 0$ extrapolation becomes less sensitive to the fit function, the fit range, and the choice of the renormalization scale; the systematic error associated with these factors is considerably reduced.

    ↳ hep-lathep-phhep-thPTEP(2019)·43 citations
31. 31*

    Modular Symmetries and the Swampland Conjectures

    Eduardo Gonzalo🇪🇸 · Luis E. Ibáñez🇪🇸 · Ángel M. Uranga🇪🇸

    Recent string theory tests of swampland ideas like the distance or the dS conjectures have been performed at weak coupling. Testing these ideas beyond the weak coupling regime remains challenging. We propose to exploit the modular symmetries of the moduli effective action to check swampland constraints beyond perturbation theory. As an example we study the case of heterotic 4d $\mathcal{N}=1$ compactifications, whose non-perturbative effective action is known to be invariant under modular symmetries acting on the Kähler and complex structure moduli, in particular $SL(2,Z)$ T-dualities (or subgroups thereof) for 4d heterotic or orbifold compactifications. Remarkably, in models with non-perturbative superpotentials, the corresponding duality invariant potentials diverge at points at infinite distance in moduli space. The divergence relates to towers of states becoming light, in agreement with the distance conjecture. We discuss specific examples of this behavior based on gaugino condensation in heterotic orbifolds. We show that these examples are dual to compactifications of type I' or Horava-Witten theory, in which the $SL(2,Z)$ acts on the complex structure of an underlying 2-torus, and the tower of light states correspond to D0-branes or M-theory KK modes. The non-perturbative examples explored point to potentials not leading to weak coupling at infinite distance, but rather diverging in the asymptotic corners of moduli space, dynamically forbidding the access to points with global symmetries. We perform a study of general modular invariant potentials and find that there are dS maxima and saddle points but no dS minima, and that all examples explored obey the refined dS conjecture.

    ↳ hep-thhep-phJHEP(2019)·80 citations
32. 32*

    Dynamically generated magnetic moment in the Wigner-function formalism

    Shijun Mao🇨🇳 · Dirk H. Rischke🇩🇪

    We study how the mass and magnetic moment of the quarks are dynamically generated in nonequilibrium quark matter. We derive the equal-time transport and constraint equations for the quark Wigner function in a magnetized quark model and solve them in the semi-classical expansion. The quark mass and magnetic moment are self-consistently coupled to the Wigner function and controlled by the kinetic equations. While the quark mass is dynamically generated at the classical level, the quark magnetic moment is a pure quantum effect, induced by the quark spin interaction with the external magnetic field.

    ↳ hep-thhep-phnucl-thPLB(2019)·18 citations
33. 33*

    Searching for Dark Matter with $t\overline{t}$ Resonance

    Yoav Afik🇮🇱 · Eitan Gozani🇮🇱 · Yoram Rozen🇮🇱

    Many models containing particles which are candidates for dark matter, assume the standard model particles and the dark matter candidates are mediated by a spin-0 particle. At the LHC, one can use these models for dark matter searches. One of the possible approaches for the search of these models is by considering the decay of the spin-0 particle to a pair of $t\bar{t}$, thus modifying the pattern of the top quark pair invariant mass spectrum. This search suggests a good sensitivity in a parameter space different than the more traditional searches. We examine this sensitivity and put limits on two benchmark models containing candidates for dark matter, using previous ATLAS results. It was found that when the mediator mass ($m_{Y_0}$) and the dark matter candidate mass ($m_{\chi }$) have values of $m_{Y_0}\sim 2\cdot m_{\chi }$, mediator masses in the range of $[400,600]$ GeV are excluded. We compare our results to direct detection experiments and show that we gain sensitivity for new regions which are not covered by other searches.

    ↳ hep-exhep-phEPJC(2019)·2 citations
34. 34*

    Future Opportunities in Accelerator-based Neutrino Physics

    Andrea Dell'Acqua🇨🇭 · Antoni Aduszkiewicz🇵🇱 · Markus Ahlers🇩🇰 · Hiroaki Aihara🇯🇵 · Tyler Alion🇬🇧 · Saul Alonso Monsalve🇨🇭 · Luis Alvarez Ruso🇪🇸 · Vito Antonelli🇮🇹 · Marta Babicz🇨🇭 · Anastasia Maria Barbano🇨🇭 · Pasquale di Bari🇬🇧 · Eric Baussan🇫🇷 and 131 other authors

    This document summarizes the conclusions of the Neutrino Town Meeting held at CERN in October 2018 to review the neutrino field at large with the aim of defining a strategy for accelerator-based neutrino physics in Europe. The importance of the field across its many complementary components is stressed. Recommendations are presented regarding the accelerator based neutrino physics, pertinent to the European Strategy for Particle Physics. We address in particular i) the role of CERN and its neutrino platform, ii) the importance of ancillary neutrino cross-section experiments, and iii) the capability of fixed target experiments as well as present and future high energy colliders to search for the possible manifestations of neutrino mass generation mechanisms.

    ↳ hep-exhep-ph3 citations
35. 35*

    Dynamics of relativistic spin-polarized fluids

    Wojciech Florkowski🇵🇱 · Bengt Friman🇩🇪 · Amaresh Jaiswal🇮🇳 · Radoslaw Ryblewski🇵🇱 · Enrico Speranza🇩🇪

    We briefly review the foundations of a new relativistic fluid dynamics framework for polarized systems of particles with spin one half. Using this approach we numerically study the dynamics of the spin polarization of a rotating medium resembling the ones created in high-energy heavy-ion collisions.

    ↳ nucl-thhep-phActa Phys.Polon.Supp.(2019)·2 citations
36. 36*

    Monopole Dominance of Confinement in SU(3) Lattice QCD

    Hideo Suganuma (Kyoto U.)🇯🇵 · Naoyuki Sakumichi (Ochanomizu U.)🇯🇵

    To check the dual superconductor picture for the quark-confinement mechanism, we evaluate monopole dominance as well as Abelian dominance of quark confinement for both quark-antiquark and three-quark systems in SU(3) quenched lattice QCD in the maximally Abelian (MA) gauge. First, we examine Abelian dominance for the static $Q\bar{Q}$ system in lattice QCD with various spacing $a$ at $\beta$=5.8-6.4 and various size $L^3$x$L_t$. For large physical-volume lattices with $La\ge$ 2fm, we find perfect Abelian dominance of the string tension for the $Q\bar{Q}$ systems: ${\sigma }_{Abel}\simeq \sigma$. Second, we accurately measure the static 3Q potential for more than 300 different patterns of 3Q systems with 1000-2000 gauge configurations using two large physical-volume lattices: ($\beta$,$L^3$x$L_t$)=(5.8,$16^3$x32) and (6.0,$20^3$x32). For all the distances, the static 3Q potential is found to be well described by the Y-Ansatz: two-body Coulomb term plus three-body Y-type linear term $\sigma L_{min}$, where $L_{min}$ is the minimum flux-tube length connecting the three quarks. We find perfect Abelian dominance of the string tension also for the 3Q systems: ${\sigma }_{3Q}^{Abel}\simeq {\sigma }_{3Q}\simeq \sigma$. Finally, we accurately investigate monopole dominance in SU(3) lattice QCD at $\beta$=5.8 on $16^3$x32 with 2,000 gauge configurations. Abelian-projected QCD in the MA gauge has not only the color-electric current $j^{\mu }$ but also the color-magnetic monopole current $k^{\mu }$, which topologically appears. By the Hodge decomposition, the Abelian-projected QCD system can be divided into the monopole part ($k_{\mu }\ne 0$, $j_{\mu }=0$) and the photon part ($j_{\mu }\ne 0$, $k_{\mu }=0$). We find monopole dominance of the string tension for $Q\bar{Q}$ and 3Q systems: ${\sigma }_{Mo}\simeq 0.92\sigma$. While the photon part has almost no confining force, the monopole part almost keeps the confining force.

    ↳ hep-lathep-phhep-thPoS(2019)·4 citations
37. 37*

    Non-Abelian Higgs Theory in a Strong Magnetic Field and Confinement

    Hideo Suganuma (Kyoto U.)🇯🇵

    The non-abelian Higgs (NAH) theory is studied in a strong magnetic field. For simplicity, we study the SU(2) NAH theory with the Higgs triplet in a constant strong magnetic field $\vec{B}$, where the lowest-Landau-level (LLL) approximation can be used. Without magnetic fields, charged vector fields $A_{\mu }^{\pm }$ have a large mass $M$ due to Higgs condensation, while the photon field $A_{\mu }$ remains to be massless. In a strong constant magnetic field near and below the critical value $e{B}_c\equiv M^2$, the charged vector fields $A_{\mu }^{\pm }$ behave as 1+1-dimensional quasi-massless fields, and give a strong correlation along the magnetic-field direction between off-diagonal charges coupled with $A_{\mu }^{\pm }$. This may lead a new type of confinement caused by charged vector fields $A_{\mu }^{\pm }$.

    ↳ hep-thhep-phPoS(2018)·1 citation
38. 38*

    Finding the Scatterers in Hot Quark Soup

    Francesco D'Eramo🇮🇹 · Krishna Rajagopal🇺🇸 · Yi Yin🇺🇸

    We present a brief report on a thought experiment in which an incident energetic parton traverses a brick of quark-gluon plasma (QGP), see arXiv:1808.03250 for the full report. We calculate the probability of detecting a parton showing up at a large angle with respect to its initial direction due to scattering with the constituents of QGP, using leading order perturbative QCD. We include all relevant channels, including the Rutherford-like channel as considered in early works, and those that are not Rutherford-like but become important at a large angle. The resulting probability distributions contain information about the short distance structure of QGP. Our results provide key theoretical input toward finding the scatterers within the QGP liquid, which in turn is the necessary first step toward using precise, high-statistics, suitably differential measurements of jet modification in heavy ion collisions to study the evolution of the properties of QGP with changing resolution scale.

    ↳ nucl-thhep-phPoS(2018)·1 citation
39. 39*

    Evolution of dark matter velocity dispersion

    Alaric Erschfeld🇩🇪 · Stefan Floerchinger🇩🇪

    Cosmological perturbation theory for the late Universe dominated by dark matter is extended beyond the perfect fluid approximation by taking the dark matter velocity dispersion tensor as an additional field into account. A proper tensor decomposition of the latter leads to two additional scalar fields, as well as a vector and a tensor field. Most importantly, the trace of the velocity dispersion tensor can have a spatially homogeneous and isotropic expectation value. While it decays at early times, we show that a back-reaction effect quadratic in perturbations makes it grow strongly at late times. We compare sterile neutrinos as a candidate for comparatively warm dark matter to weakly interacting massive particles as a rather cold dark matter candidate and show that the late time growth of velocity dispersion is stronger for the latter. Another feature of a non-vanishing velocity dispersion expectation value is that it destroys the apparent self-consistency of the single-stream approximation and allows thereby to treat times and scales beyond shell-crossing.

    ↳ astro-ph.COhep-phJCAP(2019)·24 citations
40. 40*

    Novel Black-Hole Solutions in Einstein-Scalar-Gauss-Bonnet Theories with a Cosmological Constant

    Athanasios Bakopoulos🇬🇷 · Georgios Antoniou🇺🇸 · Panagiota Kanti🇬🇷

    We consider the Einstein-scalar-Gauss-Bonnet theory in the presence of a cosmological constant $\Lambda$, either positive or negative, and look for novel, regular black-hole solutions with a non-trivial scalar hair. We first perform an analytic study in the near-horizon asymptotic regime, and demonstrate that a regular black-hole horizon with a non-trivial hair may be always formed, for either sign of $\Lambda$ and for arbitrary choices of the coupling function between the scalar field and the Gauss-Bonnet term. At the far-away regime, the sign of $\Lambda$ determines the form of the asymptotic gravitational background leading either to a Schwarzschild-Anti-de Sitter-type background ($\Lambda <0$) or a regular cosmological horizon ($\Lambda >0$), with a non-trivial scalar field in both cases. We demonstrate that families of novel black-hole solutions with scalar hair emerge for $\Lambda <0$, for every choice of the coupling function between the scalar field and the Gauss-Bonnet term, whereas for $\Lambda >0$, no such solutions may be found. In the former case, we perform a comprehensive study of the physical properties of the solutions found such as the temperature, entropy, horizon area and asymptotic behaviour of the scalar field.

    ↳ hep-thgr-qchep-phPRD(2019)·100 citations
41. 41*

    Topological Data Analysis for the String Landscape

    Alex Cole🇺🇸 · Gary Shiu🇺🇸

    Persistent homology computes the multiscale topology of a data set by using a sequence of discrete complexes. In this paper, we propose that persistent homology may be a useful tool for studying the structure of the landscape of string vacua. As a scaled-down version of the program, we use persistent homology to characterize distributions of Type IIB flux vacua on moduli space for three examples: the rigid Calabi-Yau, a hypersurface in weighted projective space, and the symmetric six-torus $T^6=(T^2{)}^3$. These examples suggest that persistence pairing and multiparameter persistence contain useful information for characterization of the landscape in addition to the usual information contained in standard persistent homology. We also study how restricting to special vacua with phenomenologically interesting low-energy properties affects the topology of a distribution.

    ↳ hep-thastro-ph.COhep-phmath.ATJHEP(2019)·63 citations
42. 42*

    Sourced Scalar Fluctuations in Bouncing Cosmology

    Ido Ben-Dayan🇮🇱 · Judy Kupferman🇮🇱

    We calculate the scalar power spectrum generated by sourced fluctuations due to coupling between the scalar field, which holds most of the energy density of the universe, and a gauge field for a general FLRW metric. For this purpose we calculate the curvature perturbation to second order in the presence of gauge fields, and show that the gauge fields behave like an additional potential term. We then apply the analysis to the case of slow-contraction. Due to the interaction between the scalar field and gauge fields additional 'sourced' tensor and scalar spectra are generated. The resulting spectra are chiral, slightly blue and arbitrarily close to scale invariance. The only difference between the tensor and scalar spectra is the coupling constant with an $\mathcal{O}(1)$ numerical coefficient, and some momentum space polarization vectors. As a result the tilt of the spectra are the same. For the nearly scale invariant case, the momentum integration gives the same leading contribution. Hence, $r\simeq 1/9$ where the deviation from this value is controlled by the deviation from scale invariance, and is not in agreement with CMB observations. Deviating considerably from near scale invariance, and considering a bluer tilt with $n_T>0.12$, the model cannot account for CMB observations, but can be detected by LIGO and/or LISA in the future.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2019)·17 citations
43. 43*

    The dark matter interpretation of the 3.5-keV line is inconsistent with blank-sky observations

    Christopher Dessert🇺🇸 · Nicholas L. Rodd🇺🇸 · Benjamin R. Safdi🇺🇸

    Observations of nearby galaxies and galaxy clusters have reported an unexpected X-ray emission line around 3.5 kilo-electron volts (keV). Proposals to explain this line include decaying dark matter$-$in particular, that the decay of sterile neutrinos with a mass around 7 keV could match the available data. If this interpretation is correct, the 3.5 keV line should also be emitted by dark matter in the halo of the Milky Way. We used more than 30 megaseconds of XMM-Newton (X-ray Multi-Mirror Mission) blank-sky observations to test this hypothesis, finding no evidence of the 3.5-keV line emission from the Milky Way halo. We set an upper limit on the decay rate of dark matter in this mass range, which is inconsistent with the possibility that the 3.5-keV line originates from dark matter decay.

    ↳ astro-ph.COastro-ph.HEhep-phScience(2020)·134 citations
44. 44*

    A Global Analysis of Dark Matter Signals from 27 Dwarf Spheroidal Galaxies using 11 Years of Fermi-LAT Observations

    Sebastian Hoof🇩🇪 · Alex Geringer-Sameth🇬🇧 · Roberto Trotta🇬🇧

    We search for a dark matter signal in 11 years of Fermi-LAT gamma-ray data from 27 Milky Way dwarf spheroidal galaxies with spectroscopically measured $J$-factors. Our analysis includes uncertainties in $J$-factors and background normalisations and compares results from a Bayesian and a frequentist perspective. We revisit the dwarf spheroidal galaxy Reticulum II, confirming that the purported gamma-ray excess seen in Pass 7 data is much weaker in Pass 8, independently of the statistical approach adopted. We introduce for the first time posterior predictive distributions to quantify the probability of a dark matter detection from another dwarf galaxy given a tentative excess. A global analysis including all 27 dwarfs shows no indication for a signal in nine annihilation channels. We present stringent new Bayesian and frequentist upper limits on the dark matter cross section as a function of dark matter mass. The best-fit dark matter parameters associated with the Galactic Centre excess are excluded by at least 95% confidence level/posterior probability in the frequentist/Bayesian framework in all cases. However, from a Bayesian model comparison perspective, dark matter annihilation within the dwarfs is not strongly disfavoured compared to a background-only model. These results constitute the highest exposure analysis on the most complete sample of dwarfs to date. Posterior samples and likelihood maps from this study are publicly available.

    ↳ astro-ph.COastro-ph.HEhep-phJCAP(2020)·150 citations
45. 45*

    Charmonium decay widths in magnetized matter

    Amruta Mishra🇮🇳 · Amal Jahan CS🇮🇳 · Shivam Kesarwani🇮🇳 · Haresh Raval🇮🇳 · Shashank Kumar🇮🇳 · Jitendra Meena🇮🇳

    We study the partial decay widths of the charmonium states ($J/\psi$, $\psi (3686)$, $\psi (3770)$, ${\chi }_{c0}$, ${\chi }_{c2}$) to $D\bar{D}$ ($D^{+}{D}^{-}$ or $D^0\overline{D^0}$) in isospin asymmetric nuclear matter, in the presence of strong magnetic fields. The in-medium partial decay widths of charmonium states to $D\bar{D}$ are calculated within a light quark--antiquark pair creation model, namely the ${}^3{P}_0$ model, using the in--medium masses of the charmonia as well as $D$ and $\bar{D}$ mesons in the magnetized nuclear matter obtained within a chiral effective model. The presence of a magnetic field leads to Landau quantization of the energy levels of the proton in the nuclear medium. The effects of magnetic field and isospin asymmetry on the charmonium decay widths to $D\bar{D}$ are found to be quite prominent. The effects of the anomalous magnetic moments have also been taken into consideration for obtaining the in-medium masses of these heavy flavour mesons, used to calculate the partial decay widths of the charmonium states. The medium modifications of the charmonium decay widths can have observable consequences on the production of the charmed mesons in high energy asymmetric heavy ion collision experiments.

    ↳ nucl-thhep-phEPJA(2019)·29 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.