Mon·Jul 8, 2019Monday·July 8, 2019

1. 01*

   Strong CP problem with low-energy emergent QCD: The 4321 case

   Javier Fuentes-Martin🇨🇭 · Mario Reig🇪🇸 · Avelino Vicente🇪🇸

   We analyze the strong CP problem and the implications for axion physics in the context of $U_1$ vector leptoquark models, recently put forward as an elegant solution to the hints of lepton flavor universality violation in B-meson decays. It is shown that in minimal gauge models containing the $U_1$ as a gauge boson, the Peccei-Quinn solution of the strong CP problem requires the introduction of two axions. Characteristic predictions for the associated axions can be deduced from the model parameter space hinted by B-physics, allowing the new axion sector to account for the dark matter of the Universe. We also provide a specific ultraviolet completion of the axion sector that connects the Peccei-Quinn mechanism to the generation of neutrino masses.

   hep-phPRD(2019)·48 citations
2. 02*

   Skewness of the elliptic flow distribution in $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 5.02~TeV PbPb collisions from HYDJET++ model

   P. Cirkovic🇷🇸 · J. Milosevic🇷🇸 · L. Nadderd🇷🇸 · F. Wang🇺🇸 · X. Zhu🇨🇳

   The elliptic flow ($v_2$) event-by-event fluctuations in PbPb collisions at 5.02~TeV are analyzed within the HYDJET++ model. Using the multi-particle, so called Q-cumulant method, $v_2\{2\}$, $v_2\{4\}$, $v_2\{6\}$ and $v_2\{8\}$ are calculated and used to study their ratios and to construct skewness (${\gamma }_1^{exp}$) as a measure of the asymmetry of the elliptic flow distribution. Additionally, in order to check if there is a hydrodynamics nature in the elliptic collectivity generated by the HYDJET++ model, the ratio of $v_2\{6\}-v_2\{8\}$ and $v_2\{4\}-v_2\{6\}$ distribution is calculated. The analysis is performed as a function of the collision centrality. In order to check the HYDJET++ model responses, the results of this analysis are compared to the corresponding experimental measurements by CMS. A good qualitative and rather good quantitative agreement is found.

   hep-phnucl-thPRC(2020)·2 citations
3. 03*

   Heavy long-lived fractionally charged leptons in novel $3-3-1$ model

   Elmer Ramirez Barreto🇵🇪 · David Romero Abad🇵🇪

   It was explored a new $SU(3{)}_L\otimes U(1{)}_X$ electroweak extension of the Standard Model, where new particles arise with peculiar signatures as heavy fractionally charged leptons and electrical neutral quarks, among others. We examine the branching fraction and the lifetime of new heavy leptons in order to discriminate if they could be identified as long-lived particle candidates. In addition, it was compared the production cross-section for these exotic leptons through a Drell-Yan process for the LHC and future hadron facilities.

   hep-ph6 citations
4. 04*

   Lepton specific two-Higgs-doublet model based on a $U(1{)}_X$ gauge symmetry with dark matter

   Takaaki Nomura🇰🇷 · Prasenjit Sanyal🇮🇳

   We discuss a two Higgs doublet model with extra $U(1{)}_X$ gauge symmetry where lepton specific (type-X) structure for Yukawa interactions is realized by charge assignment of fields under the $U(1{)}_X$. Extra charged leptons are introduced to cancel gauge anomaly associated with extra gauge symmetry. In addition, we introduce scalar fields as dark matter candidates to which we assign $Z_2$ odd parity for guaranteeing stability of them. We then analyze phenomenology of the model such as scalar potential, muon anomalous magnetic dipole moment, collider physics associated with $Z^{\prime }$ boson from $U(1{)}_X$, and dark matter physics. Carrying out numerical analysis we search for phenomenologically viable parameter region.

   hep-phhep-exPRD(2019)·8 citations
5. 05*

   Connecting ANITA Anomalous Events to a Non-thermal Dark Matter Scenario

   Debasish Borah🇮🇳 · Arnab Dasgupta🇰🇷 · Ujjal Kumar Dey🇰🇷 · Gaurav Tomar🇰🇷

   The ANtarctic Impulsive Transient Antenna (ANITA) collaboration has observed two EeV-energy, upward going events originating from below the horizon. As no standard model (SM) particles, propagating through the earth at such energy and exit angles, can give rise to the required survival probability for the observed events, several beyond standard model (BSM) proposals have come up. We propose a scenario where a $Z_2$ odd sector is responsible for such anomalous events. The next to lightest $Z_2$ odd particle or the next to lightest stable particle (NLSP), created from ultra high energy neutrino interactions with nucleons, can pass through the earth and then decay into the lightest $Z_2$ odd particle or the lightest stable particle (LSP) and a tau lepton. The long-lived nature of the NLSP requires its coupling with the LSP to be very small, keeping the LSP out of thermal equilibrium in the early universe. The LSP can then be a non-thermal dark matter while the tau leptons produced from NLSP decay after passing through the earth can explain the ANITA events. We first show that a purely non-thermal dark matter scenario can not give rise to the required event rates while a hybrid scenario where dark matter can have both thermal as a well non-thermal contribution to its relic abundance, serves the purpose.

   hep-phastro-ph.COastro-ph.HEPRD(2020)·25 citations
6. 06*

   Ad Lucem: QED Parton Distribution Functions in the MMHT Framework

   L. A. Harland-Lang🇬🇧 · A. D. Martin🇬🇧 · R. Nathvani🇬🇧 · R. S. Thorne🇬🇧

   We present the MMHT2015qed PDF set, resulting from the inclusion of QED corrections to the existing set of MMHT Parton Distribution Functions (PDFs), and which contain the photon PDF of the proton. Adopting an input distribution from the LUXqed formulation, we discuss our methods of including QED effects for the full, coupled DGLAP evolution of all partons with QED at $\mathcal{O}(\alpha )$, $\mathcal{O}(\alpha {\alpha }_S)$, $\mathcal{O}({\alpha }^2)$. While we find consistency for the photon PDF of the proton with other recent sets, building on this we also present a set of QED corrected neutron PDFs and provide the photon PDF separated into its elastic and inelastic contributions. The effect of QED corrections on the other partons and the fit quality is investigated, and the sources of uncertainty for the photon are outlined. Finally we explore the phenomenological implications of this set, giving the partonic luminosities for both the elastic and inelastic contributions to the photon and the effect of our photon PDF on fits to high mass Drell-Yan production, including the photon--initiated channel.

   hep-phhep-exEPJC(2019)·76 citations
7. 07*

   Fluctuations of identified particle yields using the {\nu} dyn variable at energies available at the BNL Relativistic Heavy Ion Collider

   Vivek Kumar Singh🇮🇳 · D. K. Mishra🇮🇳 · Zubayer Ahammed🇮🇳

   We study the fluctuations of net-charge, net-pion, net-kaon and net-proton using $D$-measure and ${\nu }_{dyn}$ variables in heavy-ion jet interaction generator (HIJING), ultra-relativistic quantum molecular dynamics (UrQMD), and hadron resonance gas (HRG) model at different collision energies \sqsn. It has been observed that, the values of $D$ strongly dependent on $\Delta \eta$ in HIJING and UrQMD models and independent in HRG model. The diffusion coefficients ($\sigma$) of identified particles are estimated at various \sqsn. It is observed that, the $\sigma$ values are independent of collision energies but emphasizes the particle species dependence of diffusion coefficient in the QGP medium. This study provides a realistic baseline for comparison with the experimental data.

   hep-phnucl-thPRC(2020)·6 citations
8. 08*

   Non-relativistic Effective Interactions of Spin 1 Dark Matter

   Riccardo Catena🇸🇪 · Kåre Fridell🇩🇪 · Martin B. Krauss🇸🇪

   We investigate the non-relativistic reduction of simplified models for spin 1 dark matter (DM) with the aim of identifying features in the phenomenology of DM-quark interactions which are specific to vector DM. In the case of DM-quark interactions mediated by a spin 1 particle, we find two DM-nucleon interaction operators arising from the non-relativistic reduction of simplified models for spin 1 DM that are specific to spin 1 DM, and which were not considered in previous studies. They are quadratic in the momentum transfer, linear in a symmetric combination of polarisation vectors for the DM particle, and arise from simplified models which do not generate momentum transfer independent operators as leading interactions in the non-relativistic expansion of DM-nucleon scattering amplitudes. Within these simplified models, the new operators cannot be neglected when computing DM signals at direct detection experiments. For example, we find that nuclear recoil energy spectra computed by including or neglecting the new operators can differ by up to one order of magnitude for nuclear recoil energies larger than about 20 keV and DM masses below $50$ GeV. Furthermore, the shape of the expected nuclear recoil spectra depends significantly on whether the new operators are taken into account or not. Finally, neglecting the contribution to DM direct detection signals from the new operators leads to inaccurate conclusions when assessing the compatibility of a future direct detection signal with CMB constraints on the DM relic density, especially when the number of signal events is small, e.g. $\mathcal{O}(1)$.

   hep-phastro-ph.COJHEP(2019)·35 citations
9. 09*

   Alternative Renormalizable Minimal SO(10) GUTs and Data Fitting

   Takeshi Fukuyama🇯🇵 · Nobuchika Okada🇺🇸 · Hieu Minh Tran🇻🇳

   The alternative renormalizable minimal $SO(10)$ model is composed of the Yukawa couplings with $\text{10}\oplus \text{120}$ Higgs fields, whereas the right-handed (RH) neutrino Majorana masses are generated via the Witten mechanism. The gauge coupling unification is achieved together with a unique pattern of the fermion masses and mixing at the grand unification scale due to additional contributions of vector-like quarks to the standard model renormalization group equations. We perform the fitting of the model to the experimental data of charged fermion masses and the CKM matrix. The best fit point is obtained with large pulls for $m_c$, $m_s$, $m_b$, and $m_{\tau }$. For the modifications to the minimal model by adding either ${\text{10}}^{\prime }$ or ${\text{120}}^{\prime }$, a large deviation for the tau mass rules out all these models. In the case with the bottom and vector-like quark mixing, the mass matrices are well fitted the charged fermions but the bound on the light neutrino mass scale excludes this scenario. To ameliorate this deficit, we consider the two-step symmetry breaking scenario, $SO(10)\to SU(5)\to SU(3{)}_C\times SU(2{)}_L\times U(1{)}_Y$, with the $SO(10)$ breaking at the Planck scale leading to the radiatively generated RH neutrino Majorana masses being at the ordinary seesaw scale. For this case, we find the best fit point with ${\chi }^2=7.8$ consistent with experimental results including the neutrino sector. The largest deviation is 2.3$\sigma$ corresponding to the strange quark mass. Hence, a more precise determination of the strange quark mass can test this model. For the best fit point, we find the effective Majorana neutrino mass of $m_{\beta \beta }=0.22$ meV and the sum of light neutrino masses as $\Sigma =0.078$ eV, which are consistent with the current constraints from the search for the neutrinoless double beta decay and the CMB anisotropy measurement.

   hep-phNPB(2020)·8 citations
10. 10*

    Higher-Order Sudakov Resummation in Coupled Gauge Theories

    Georgios Billis🇩🇪 · Frank J. Tackmann🇩🇪 · Jim Talbert🇩🇪

    We consider the higher-order resummation of Sudakov double logarithms in the presence of multiple coupled gauge interactions. The associated evolution equations depend on the coupled $\beta$ functions of two (or more) coupling constants ${\alpha }_a$ and ${\alpha }_b$, as well as anomalous dimensions that have joint perturbative series in ${\alpha }_a$ and ${\alpha }_b$. We discuss possible strategies for solving the system of evolution equations that arises. As an example, we obtain the complete three-loop (NNLL) QCD$\otimes$QED Sudakov evolution factor. Our results also readily apply to the joint higher-order resummation of electroweak and QCD Sudakov logarithms. As part of our analysis we also revisit the case of a single gauge interaction (pure QCD), and study the numerical differences and reliability of various methods for evaluating the Sudakov evolution factor at higher orders. We find that the approximations involved in deriving commonly used analytic expressions for the evolution kernel can induce noticeable numerical differences of several percent or more at low scales, exceeding the perturbative precision at N${}^3$LL and in some cases even NNLL. Therefore, one should be cautious when using approximate analytic evolution kernels for high-precision analyses.

    hep-phJHEP(2020)·41 citations
11. 11*

    Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks

    B. M. Roberts🇫🇷 · P. Delva🇫🇷 · A. Al-Masoudi🇩🇪 · A. Amy-Klein🇫🇷 · C. Bærentsen🇫🇷 · C. F. A. Baynham🇬🇧 · E. Benkler🇩🇪 · S. Bilicki🇫🇷 · S. Bize🇫🇷 · W. Bowden🇬🇧 · J. Calvert🇫🇷 · V. Cambier🇫🇷 and 42 other authors

    We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network, we significantly improve the constraints on transient variations of the fine structure constant. For example, we constrain the variation in alpha to <5*10^-17 for transients of duration 10^3 s. This analysis also presents a possibility to search for dark matter, the mysterious substance hypothesised to explain galaxy dynamics and other astrophysical phenomena that is thought to dominate the matter density of the universe. At the current sensitivity level, we find no evidence for dark matter in the form of topological defects (or, more generally, any macroscopic objects), and we thus place constraints on certain potential couplings between the dark matter and standard model particles, substantially improving upon the existing constraints, particularly for large (>~10^4 km) objects.

    ↳ astro-ph.COhep-phphysics.atom-phNew J.Phys.(2020)·63 citations
12. 12*

    Weak equivalence principle, swampland and $H_0$ tension with fast single radio bursts FRB 180924 and FRB 190523

    Deng Wang🇨🇳 · Zhaozhou Li🇨🇳 · Jiajun Zhang🇨🇳

    Two new fast single radio bursts FRB 180924 and FRB 190523 well localized to massive galaxies have opened a new window to probe and characterize how cosmic baryons are allocated between galaxies, their surroundings and intergalactic medium. We are motivated by testing Einstein's weak equivalence principle with these two cosmic transients which have accurate redshifts. Using photons with different energies emitted by FRB 180924, we obtain, so far, the most stringent bound $\Delta \gamma <2.16\times 10^{-10}$ for non-repeating FRBs with accurate redshifts when only considering the gravitational potential of the Milk Way. If using the gravitational potential of the Laniakea supercluster instead of the Milk Way one, we also obtain the strictest bound $\Delta \gamma <1.06\times 10^{-14}$ to date. In light of rapid progress of FRB cosmology, towards the next two decades, we give an universal limitation $\Delta \gamma <8.24\times 10^{-22}$ from photons with different energies emitted by single FRBs with accurate redshifts. Moreover, we analyze detailedly the effects of various astrophysical parameters on the precision of weak equivalence principle. We also estimate the abilities of single FRBs with known redshifts to test the validity of swampland criterion, and to distinguish which value of $H_0$ is preferred.

    ↳ astro-ph.COgr-qchep-phPhys.Dark Univ.(2020)·10 citations
13. 13*

    Observational Constraints on Warm Inflation in Loop Quantum Cosmology

    Micol Benetti🇮🇹 · Leila Graef🇧🇷 · Rudnei O. Ramos🇧🇷

    By incorporating quantum aspects of gravity, Loop Quantum Cosmology (LQC) provides a self-consistent extension of the inflationary scenario, allowing for modifications in the primordial inflationary power spectrum with respect to the standard General Relativity one. We investigate such modifications and explore the constraints imposed by the Cosmic Microwave Background (CMB) Planck Collaboration data on the Warm Inflation (WI) scenario in the LQC context. We obtain useful relations between the dissipative parameter of WI and the bounce scale parameter of LQC. We also find that the number of required e-folds of expansion from the bounce instant till the moment the observable scales crossed the Hubble radius during inflation can be smaller in WI than in CI. In particular, we find that this depends on how large is the dissipation in WI, with the amount of required e-folds decreasing with the increasing of the dissipation value. Furthermore, by performing a Monte Carlo Markov Chain analysis for the considered WI models, we find good agreement of the model with the data. This shows that the WI models studied here can explain the current observations also in the context of LQC.

    ↳ astro-ph.COgr-qchep-phJCAP(2019)·27 citations
14. 14*

    Hot quark matter and (proto-) neutron stars

    G. Malfatti🇦🇷 · M. Orsaria🇦🇷 · G. A. Contrera🇦🇷 · F. Weber🇺🇸 · I. F. Ranea-Sandoval🇦🇷

    In part one of this paper, we use a non-local extension of the 3-flavor Polyakov-Nambu-Jona-Lasinio model, which takes into account flavor-mixing, momentum dependent quark masses, and vector interactions among quarks, to investigate the possible existence of a spinodal region (determined by the vanishing of the speed of sound) in the QCD phase diagram and determine the temperature and chemical potential of the critical end point. In part two of the paper, we investigate the quark-hadron composition of baryonic matter at zero as well as non-zero temperature. This is of great topical interest for the analysis and interpretation of neutron star merger events such as GW170817. With this in mind, we determine the composition of proto-neutron star matter for entropies and lepton fractions that are typical of such matter. These compositions are used to delineate the evolution of proto-neutron stars to neutron stars in the baryon-mass versus gravitational-mass diagram. The hot stellar models turn out to contain significant fractions of hyperons and $\Delta$-isobars but no deconfined quarks. The latter, are found to exist only in cold neutron stars.

    ↳ nucl-thastro-ph.HEhep-phphysics.space-phPRC(2019)·60 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.