Tue·Sep 15, 2020Tuesday·September 15, 2020

1. 01*

   Minimal Froggatt-Nielsen Textures

   Marco Fedele🇪🇸 · Alessio Mastroddi🇮🇹 · Mauro Valli🇺🇸

   The flavour problem of the Standard Model can be addressed through the Froggatt-Nielsen (FN) mechanism. In this work, we develop an approach to the study of FN textures building a direct link between FN-charge assignments and the measured masses and mixing angles via unitary transformations in flavour space. We specifically focus on the quark sector to identify the most economic FN models able to provide a dynamical and natural understanding of the flavour puzzle. Remarkably, we find viable FN textures, involving charges under the horizontal symmetry that do not exceed one in absolute value (in units of the flavon charge). Within our approach, we also explore the degree of tuning of FN models in solving the flavour problem via a measure analogous to the Barbieri-Giudice one. We find that most of the solutions do not involve peculiar cancellations in flavour space.

   hep-phJHEP(2021)·36 citations
2. 02*

   Possible manifestation of the 2p pionium in particle physics processes

   Peter Lichard🇨🇿

   We suggest a few particle physics processes in which excited 2p pionium ${\mathrm{A}}_{2\pi }^{\prime }$ may be observed. They include the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ annihilation, the $V^0\to {\pi }^0{\ell }^{+}{\ell }^{-}$ and $K^{\pm }\to {\pi }^{\pm }{\ell }^{+}{\ell }^{-}$ ($\ell =e,\mu$) decays, and the photoproduction of two neutral pions from nucleons. We analyze available experimental data and find that they, in some cases, indicate the presence of 2p pionium, but do not provide definite proof.

   hep-phhep-exPRD(2020)·0 citations
3. 03*

   Coupled Transport Equations for Quarkonium Production in Heavy Ion Collisions

   Xiaojun Yao🇺🇸 · Weiyao Ke🇺🇸 · Yingru Xu🇺🇸 · Steffen A. Bass🇺🇸 · Berndt Müller🇺🇸

   Motivated by recent applications of the open quantum system formalism to understand quarkonium transport in the quark-gluon plasma, we develop a set of coupled Boltzmann equations for open heavy quark-antiquark pairs and quarkonia. Our approach keeps track of the correlation between the heavy quark-antiquark pair from quarkonium dissociation and thus is able to account for both uncorrelated and correlated recombination. By solving the coupled Boltzmann equations for current heavy ion collision experiments, we find correlated recombination is crucial to describe the data of bottomonia nuclear modification factors. To further test the importance of correlated recombination in experiments, we propose a new observable: $\frac{R_{AA}[{\chi }_b(1P)]}{R_{AA}[{\rm Y}(2S)]}$. Future measurements of this ratio will help distinguish calculations with and without correlated recombination.

   hep-phnucl-thPoS(2021)·2 citations
4. 04*

   Reactions Governing Strangeness Abundance in Primordial Universe

   Johann Rafelski🇺🇸 · Cheng Tao Yang🇺🇸

   Strangness production processes can balance natural strangeness decay in the early hadronic Universe. Comparing to the characteristic Hubble time $1/H$, the reaction rates for ${\mu }^{\pm }+{\nu }_{\mu }\to K^{\pm }$, $l^{-}+l^{+}\to \varphi$, and $\pi +\pi \to K$ in sequence become slower than expansion rate at $T=33.9\mathrm{MeV}$, $T=25\mathrm{MeV}$ and $T=20\mathrm{MeV}$ respectively. This means that in the antibaryon annihilation epoch near to $T\simeq 40\mathrm{MeV}$ strangeness is in chemical equilibrium.

   hep-phEPJ Web Conf.(2022)·5 citations
5. 05*

   Distribution of Nuclear Matter and Radiation in the Fragmentation Region

   Isobel Kolbé🇺🇸 · Mawande Lushozi🇺🇸 · Larry D. McLerran🇺🇸 · Gongming Yu🇺🇸

   We study the fragmentation (far forward/backward) region of heavy ion collisions by considering an at-rest nucleus which is struck by a relativistic sheet of colored glass. By means of a simple classical model, we calculate the subsequent evolution of baryons and the associated radiation. We confirm that the struck nucleus undergoes a compression and that the dynamics of the early times of the collision are best described by two separate fluids as the produced radiation's velocity distribution is very different to the velocity distribution of the matter in the struck nucleus.

   hep-phPRC(2021)·7 citations
6. 06*

   CP asymmetries of $\overline{B}\to X_s/X_d\gamma$ in models with three Higgs doublets

   A.G. Akeroyd🇬🇧 · Stefano Moretti🇬🇧 · Tetsuo Shindou🇯🇵 · Muyuan Song🇬🇧

   Direct CP asymmetries (${\mathcal{A}}_{CP}$) in the inclusive decays of $\overline{B}\to X_s\gamma$ and $\overline{B}\to X_{s+d}\gamma$ of the order of $1\%$ will be probed at the BELLE II experiment. In this work, three such asymmetries are studied in the context of a three-Higgs-doublet model (3HDM), and it is shown that all three ${\mathcal{A}}_{CP}$ can be as large as the current experimental limits. Of particular interest is ${\mathcal{A}}_{CP}$ for $\overline{B}\to X_{s+d}\gamma$, which is predicted to be effectively zero in the Standard Model (SM). A measurement of $2.5\%$ or more for this observable with the full BELLE II data would give $5\sigma$ evidence for physics beyond the SM. We display parameter space in the 3HDM for which such a clear signal is possible.

   hep-phPRD(2021)·25 citations
7. 07*

   Production of the bottomonium-like states $Z_b$ states at $e$-$h$ and ultraperipheral $h$-$h$ collisions

   Xiao-Yun Wang🇨🇳 · Wei Kou🇨🇳 · Qing-Yong Lin🇨🇳 · Ya-Ping Xie🇨🇳 · Xurong Chen🇨🇳 · Alexey Guskov🇷🇺

   The photoproduction of bottomonium-like states $Z_b(10610)$ and $Z_b(10650)$ via $\gamma p$ scattering is studied within an effectiv Lagrangian approach and the vector-meson-dominance model. The Regge model is employed to calculate the photoproduction of $Z_b$ states via $t$-channel with $\pi$ exchange.The numerical results show that the values of the total cross-sections of $Z_b(10610)$ and $Z_b(10650)$ can reach 0.09 nb and 0.02 nb, respectively, near the center of mass energy of 22 GeV. The experimental measurements and studies on the photoproduction of $Z_b$ states near energy region around $W\simeq 22$ GeV is suggested. Moreover, with the help of eSTARlight and STARlight programs, one obtains the cross-sections and event numbers of $Z_b(10610)$ production in electron-ion collision (EIC) and Ultraperipheral collisions (UPCs). The results show that a considerable number of events from $Z_b(10610)$ can be produced on the relevant experiments of EICs and UPCs. Also, one calculates the rates and kinematic distributions for $\gamma p\to Z_{b}n$ in $ep$ and $pA$ collisions via EICs and UPCs, and the relevant results will provide an important reference for the RHIC, LHC, EIC-US, LHeC, and FCC experiments to search for the bottomonium-like $Z_b$ states.

   hep-phnucl-thCPC(2021)·2 citations
8. 08*

   Search for the anomalous $WW\gamma$ couplings through the process $e^{-}{e}^{+}\to {\nu }_e{\bar{\nu }}_e\gamma$ at ILC with unpolarized and polarize beams

   S. Spor🇹🇷 · M. Köksal🇹🇷

   We investigate the anomalous $W^{+}{W}^{-}\gamma$ couplings through the process $e^{-}{e}^{+}\to {\nu }_e{\bar{\nu }}_e\gamma$ for unpolarized and polarized electron (positron) beams at the International Linear Collider. We give the 95$\%$ Confidence Level limits on the anomalous couplings with and without the systematic uncertainties for various values of center-of-mass energies and the integrated luminosities. We show that the obtained limits on the anomalous couplings through the process $e^{-}{e}^{+}\to {\nu }_e{\bar{\nu }}_e\gamma$ can highly improve the current experimental limits.

   hep-phPLB(2021)·5 citations
9. 09*

   Disentangling Boosted Higgs Boson Production Modes with Machine Learning

   Yi-Lun Chung🇹🇼 · Shih-Chieh Hsu🇺🇸 · Benjamin Nachman🇺🇸

   Higgs Bosons produced via gluon-gluon fusion (ggF) with large transverse momentum ($p_T$) are sensitive probes of physics beyond the Standard Model. However, high $p_T$ Higgs Boson production is contaminated by a diversity of production modes other than ggF: vector boson fusion, production of a Higgs boson in association with a vector boson, and production of a Higgs boson with a top-quark pair. Combining jet substructure and event information with modern machine learning, we demonstrate the ability to focus on particular production modes. These tools hold great discovery potential for boosted Higgs bosons produced via ggF and may also provide additional information about the Higgs Boson sector of the Standard Model in extreme phase space regions for other production modes as well.

   hep-phhep-exJINST(2021)·28 citations
10. 10*

    A hybrid seesaw model and hierarchical neutrino flavor structures based on $A_4$ symmetry

    Mayumi Aoki🇯🇵 · Daiki Kaneko🇯🇵

    We propose a hybrid seesaw model based on $A_4$ flavor symmetry, which generates a large hierarchical flavor structure. In our model, tree-level and one-loop seesaw mechanisms predict different flavor structures in the neutrino mass matrix, and generate a notable hierarchy among them. We find that such a hierarchical structure gives a large effective neutrino mass which can be accessible by next-generation neutrinoless double beta decay experiments. Majorana phases can also be predictable. The $A_4$ flavor symmetry in the model is spontaneously broken to the $Z_2$ symmetry, leading to a dark matter candidate which is assumed to be a neutral scalar field. The favored mass region of the dark matter is obtained by numerical computations of the relic abundance and the cross section of the nucleon. We also investigate the predictions of the several hierarchical flavor structures based on $A_4$ symmetry for the effective neutrino mass and the Majorana phases, and find the characteristic features depending on the hierarchical structures.

    hep-phPTEP(2021)·6 citations
11. 11*

    Angular analysis of $B_s\to f_2^{\prime }(1525)(\to K^{+}{K}^{-}){\mu }^{+}{\mu }^{-}$ decays as a probe to lepton flavor universality violation

    N Rajeev🇮🇳 · Niladribihari Sahoo🇬🇧 · Rupak Dutta🇮🇳

    The flavor anomalies reported in $R_K$, $R_{K^{\ast }}$, $P_5^{\prime }$ and $\mathcal{B}(B_s\to \varphi {\mu }^{+}{\mu }^{-})$ indicate lepton flavor universality violation in $b\to s{l}^{+}{l}^{-}$ quark level transition decays. The deviation from the SM prediction reported in the underlying flavor observables currently stand at the level of $2.5\sigma$, $2.4\sigma$, $3.3\sigma$ and $3.7\sigma$, respectively. In this context, we perform an angular analysis of the four-body differential decay of $B_s\to f_2^{\prime }(1525)(\to K^{+}{K}^{-}){\mu }^{+}{\mu }^{-}$ in a model independent effective field theory framework. The decay mode $B_s\to f_2^{\prime }(1525)l^{+}{l}^{-}$ undergoes similar $b\to s$ neutral current quark level transition and, in principle, can provide complementary information regarding lepton flavor universality violation in $b\to s{l}^{+}{l}^{-}$ quark level transition decays. We give predictions of various physical observables such as the branching ratio, the longitudinal polarization fraction, the forward-backward asymmetry, the angular observables $P_1$, $P_2$, $P_4^{\prime }$, $P_5^{\prime }$ and also the lepton flavor sensitive observables such as the ratio of branching ratio $R_{f_2^{\prime }}$, $Q_{F_L}$, $Q_{A_{FB}}$, $Q_1$, $Q_2$, $Q_4^{\prime }$, $Q_5^{\prime }$ for $B_s\to f_2^{\prime }(1525)(\to K^{+}{K}^{-}){\mu }^{+}{\mu }^{-}$ decays in the standard model and in the presence of several 1D and 2D new physics scenarios.

    hep-phPRD(2021)·29 citations
12. 12*

    Tribaryons in a constituent quark model

    Aaron Park🇰🇷 · Su Houng Lee🇰🇷

    We calculate the matrix elements of the color-spin interaction for all possible multi-quark states of tribaryons in flavor SU(3) broken case. For that purpose, we construct the flavor$\otimes$color$\otimes$spin wave functions of the tribaryons, which are taken to be antisymmetric to satisfy the Pauli exclusion principle. Furthermore, we analyze the diquark structure of the tribaryon configurations using the symmetric and antisymmetric basis set of flavor, color and spin states.

    hep-phnucl-thPRD(2020)·3 citations
13. 13*

    Suppression of decay widths in singly heavy baryons induced by the $U_A(1)$ anomaly

    Yohei Kawakami🇯🇵 · Masayasu Harada🇯🇵 · Makoto Oka🇯🇵 · Kei Suzuki🇯🇵

    We study strong and radiative decays of excited singly heavy baryons (SHBs) using an effective chiral Lagrangian based on the diquark picture proposed in Ref. [1]. The effective Lagrangian contains a $U_A(1)$ anomaly term, which induces an inverse mass ordering between strange and non-strange SHBs with spin-parity $1/2^{-}$. We find that the effect of the $U_A(1)$ anomaly combined with flavor-symmetry breaking modifies the Goldberger-Treiman relation for the mass difference between the ground state ${\Lambda }_Q(1/2^{+})$ and its chiral partner ${\Lambda }_Q(1/2^{-})$, and ${\Lambda }_Q(1/2^{-}){\Lambda }_Q(1/2^{+})\eta$ coupling, which results in suppression of the decay width of ${\Lambda }_Q(1/2^{-})\to {\Lambda }_Q(1/2^{+})\eta$. We also investigate the other various decays such as ${\Lambda }_Q(1/2^{-})\to {\Sigma }_Q(1/2^{+},3/2^{+})\pi \pi$, ${\Lambda }_Q(1/2^{-})\to {\Sigma }_Q(1/2^{+})\pi$, ${\Lambda }_Q(1/2^{-})\to {\Sigma }_Q(1/2^{+},3/2^{+})\gamma$, and ${\Lambda }_Q(1/2^{-})\to {\Lambda }_Q(1/2^{+}){\pi }^0$ for wide range of mass of ${\Lambda }_Q(1/2^{-})$.

    hep-phnucl-thPRD(2020)·14 citations
14. 14*

    B${}_1$B${}_{s0}$K and B${}_1$B${}_{s1}$K strong couplings in three-point QCD sum rules

    Mohammad Ali Asgarian🇮🇷

    An improved calculation of the strong coupling constants of B${}_1$B${}_{s0}$K and B${}_1$B${}_{s1}$K vertices is presented in the framework of the three-point QCD sum rules. The coupling constants are calculated, when both the B${}_{s0}$(B${}_{s1}$) and K states are off-shell. Considering the $S{U}_f(3)$ symmetry, the results are compared with the existing predictions.

    hep-ph0 citations
15. 15*

    Connecting Low scale Seesaw for Neutrino Mass to Inelastic sub-GeV Dark Matter with Abelian Gauge Symmetry

    Debasish Borah (1)🇮🇳 · Satyabrata Mahapatra (2)🇮🇳 · Narendra Sahu (2) ((1) Indian Institute of Technology Guwahati (2) Indian Institute of Technology Hyderabad)🇮🇳

    Motivated by the recently reported excess of electron recoil events by the XENON1T experiment, we propose low scale seesaw scenarios for light neutrino masses within $U(1{)}_X$ gauge extension of the standard model that also predicts stable as well as long lived dark sector particles. The new fields necessary for seesaw realisation as well as dark matter are charged under the $U(1{)}_X$ gauge symmetry in an anomaly free way. A singlet scalar field which effectively gives rise to lepton number violation and hence Majorana light neutrino masses either at tree or radiative level, also splits the dark matter field into two quasi-degenerate states. While sub-eV neutrino mass and non-zero dark matter mass splitting are related in this way, the phenomenology of sub-GeV scale inelastic dark matter can be very rich if the mass splitting is of keV scale. We show that for suitable parameter space, both the components with keV splitting can contribute to total dark matter density of the present universe, while opening up the possibility of the heavier dark matter candidate to undergo down-scattering with electrons. We check the parameter space of the model for both fermion and scalar inelastic dark matter candidates which can give rise to the XENON1T excess while being consistent with other phenomenological bounds. We also discuss the general scenario where mass splitting~$\Delta m$ between the two dark matter components can be larger, effectively giving rise to a single component dark matter scenario.

    hep-phNPB(2021)·14 citations
16. 16*

    Strong evidence of $\rho (1250)$ from a unitary multichannel reanalysis of elastic scattering data with crossing-symmetry constraints

    N. Hammoud🇵🇱 · R. Kamiński🇵🇱 · V. Nazari🇷🇺 · G. Rupp🇵🇹

    An analysis is presented of elastic $P$-wave $\pi \pi$ phase shifts and inelasticities up to 2 GeV, aimed at identifying the corresponding $J^{PC}=1^{--}$ excited $\rho$ resonances and focusing on the $\rho (1250)$ vs. $\rho (1450)$ controversy. The approach employs an improved parametrization in terms of a manifestly unitary and analytic three-channel $S$-matrix with its complex-energy pole positions. The included channels are $\pi \pi$, $\rho 2\pi$, and $\rho \rho$, the latter two being effective in the sense that they mimic several experimentally observed decay modes with nearby thresholds. In an alternative fit, the $\rho 2\pi$ mode is replaced by $\omega \pi$, which is also an experimentally relevant channel. The improvement with respect to prior work amounts to the enforcement of maximum crossing symmetry through once-subtracted dispersion relations called GKPY equations. A separate analysis concerns the pion electromagnetic form factor, which again demonstrates the enormous importance of guaranteeing unitarity and analyticity when dealing with very broad and highly inelastic resonances. In the case of $\rho (1250)$ vs. $\rho (1450)$, the failure to do so is shown to give rise to an error in the predicted mass of about 170 MeV. A clear picture emerges from these analyses, identifying five vector $\rho$ states below 2 GeV, viz. $\rho (770)$, $\rho (1250)$, $\rho (1450)$, $\rho (1600)$, and $\rho (1800)$, with $\rho (1250)$ being indisputably the most important excited $\rho$ resonance. The stability of the fits as well as the imposition of unitarity, analyticity, and approximate crossing symmetry in the analyses lend very strong support to these assignments. The possibly far-reaching consequences for meson spectroscopy are discussed.

    hep-phhep-exPRD(2020)·20 citations
17. 17*

    Studying the neutrino wave-packet effects at medium-baseline reactor neutrino oscillation experiments and the potential benefits of an extra detector

    Zhaokan Cheng🇨🇳 · Wei Wang🇨🇳 · Chan Fai Wong🇨🇳 · Jingbo Zhang🇨🇳

    We examine the potential of the future medium-baseline reactor neutrino oscillation (MBRO) experiments in studying neutrino wave-packet impact. In our study, we treat neutrinos as wave packets and use the corresponding neutrino flavor transition probabilities. The delocalization, separation and spreading of the wave packets lead to decoherence and dispersion effects, which modify the plane-wave neutrino oscillation pattern, by amounts that depend on the energy uncertainties in the initial neutrino wave packets. We find that MBRO experiments could be sensitive to the wave-packet impact, since the baseline is long enough and also the capability of observing small corrections to the neutrino oscillations due to excellent detector energy resolution. Besides studying the constraints on the decoherence parameter, we also examine the potential wave-packet impacts on the precision of measuring ${\theta }_{12}$ and other oscillation parameters in the future medium-baseline reactor neutrino oscillation experiments. Moreover, we also probe the potential benefits of an additional detector for studying such exotic neutrino physics.

    hep-phhep-exNPB(2021)·9 citations
18. 18*

    Exploring non-perturbative Sudakov factor via $Z^0$-boson production in $pp$ collisions

    Shu-yi Wei🇮🇹

    $Z^0$-boson production at low transverse momentum offers an unique opportunity to explore the non-perturbative Sudakov factor. In this paper, we employ three parameterizations of the non-perturbative Sudakov factor to calculate the ${\varphi }^{\ast }$-distribution and compare our results with the ultra precise experimental data. We extract the free parameters in each parameterization with a ${\chi }^2$ analysis. The parton-momentum-fraction dependence of these free parameters is also studied by comparing the values extracted at different collision energies and different rapidity ranges.

    hep-phPLB(2021)·11 citations
19. 19*

    PDFFlow: parton distribution functions on GPU

    Stefano Carrazza🇮🇹 · Juan M. Cruz-Martinez🇮🇹 · Marco Rossi🇮🇹

    We present PDFFlow, a new software for fast evaluation of parton distribution functions (PDFs) designed for platforms with hardware accelerators. PDFs are essential for the calculation of particle physics observables through Monte Carlo simulation techniques. The evaluation of a generic set of PDFs for quarks and gluon at a given momentum fraction and energy scale requires the implementation of interpolation algorithms as introduced for the first time by the LHAPDF project. PDFFlow extends and implements these interpolation algorithms using Google's TensorFlow library providing the capabilities to perform PDF evaluations taking fully advantage of multi-threading CPU and GPU setups. We benchmark the performance of this library on multiple scenarios relevant for the particle physics community.

    hep-phcs.LGphysics.comp-phComput.Phys.Commun.(2021)·38 citations
20. 20*

    Scalar tachyonic instabilities in gravitational backgrounds: Existence and growth rate

    L. Perivolaropoulos🇬🇷 · F. Skara🇬🇷

    It is well known that the Klein Gordon (KG) equation $\square \Phi +m^2\Phi =0$ has tachyonic unstable modes on large scales ($k^2<|m{|}^2$) for $m^2<m_{cr}^2=0$ in a flat Minkowski spacetime with maximum growth rate ${\Omega }_F(m)=|m|$ achieved at $k=0$. We investigate these instabilities in a Reissner-Nordström-deSitter (RN-dS) background spacetime with mass $M$, charge $Q$, cosmological constant $\Lambda >0$ and multiple horizons. By solving the KG equation in the range between the event and cosmological horizons, using tortoise coordinates $r_{\ast }$, we identify the bound states of the emerging Schrodinger-like Regge-Wheeler equation corresponding to instabilities. We find that the critical value $m_{cr}$ such that for $m^2<m_{cr}^2$ bound states and instabilities appear, remains equal to the flat space value $m_{cr}=0$ for all values of background metric parameters despite the locally negative nature of the Regge-Wheeler potential for $m=0$. However, the growth rate $\Omega$ of tachyonic instabilities for $m^2<0$ gets significantly reduced compared to the flat case for all parameter values of the background metric ($\Omega (Q/M,M^2\Lambda ,mM)<|m|$). This increased lifetime of tachyonic instabilities is maximal in the case of a near extreme Schwarzschild-deSitter (SdS) black hole where $Q=0$ and the cosmological horizon is nearly equal to the event horizon ($\xi \equiv 9M^2\Lambda \simeq 1$). The physical reason for this delay of instability growth appears to be the existence of a cosmological horizon that tends to narrow the negative range of the Regge-Wheeler potential in tortoise coordinates.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·8 citations
21. 21*

    The luminosity constraint in the era of precision solar physics

    Diego Vescovi🇮🇹 · Carlo Mascaretti🇮🇹 · Francesco Vissani🇮🇹 · Luciano Piersanti🇮🇹 · Oscar Straniero🇮🇹

    The luminosity constraint is a very precise relationship linking the power released by the Sun as photons and the solar neutrino fluxes. Such a relation, which is a direct consequence of the physical processes controlling the production and the transport of energy in the solar interior, is of great importance for the studies of solar neutrinos and has a special role for the search of neutrinos from the CNO cycle, whose first detection with a 5$\sigma$ significance has been recently announced by the Borexino collaboration. Here we revise the luminosity constraint, discussing and validating its underlying hypotheses, in the light of latest solar neutrino and luminosity measurements. We generalize the current formulation of the luminosity constraint relation so that it can be easily used in future analysis of solar neutrino data, and we provide a specific application showing the link between CNO and pp neutrino fluxes.

    ↳ astro-ph.SRhep-phnucl-exnucl-thJ.Phys.G(2020)·11 citations
22. 22*

    Analytic Study on Chiral Phase Transition in Holographic QCD

    Meng-Wei Li🇹🇼 · Yi Yang🇹🇼 · Pei-Hung Yuan🇨🇳

    The chiral symmetry breaking (${\chi }_{SB}$) is one of the most fundamental problems in QCD. In this paper, we calculate quark condensation analytically in a holographic QCD model dual to the Einstein-Maxwell-Dilaton (EMD) system coupled to a probe scalar field. We find that the black hole phase transition in the EMD system seriously affects ${\chi }_{SB}$. At small chemical potential, ${\chi }_{SB}$ behaves as a crossover. For large chemical potential $\mu >{\mu }_c$, ${\chi }_{SB}$ becomes first order with exactly the same transition temperature as the black hole phase transition by a bypass mechanism. The phase diagram we obtained is qualitatively consistent with the recent results from lattice QCD simulations and NJL models.

    ↳ hep-thhep-phJHEP(2021)·23 citations
23. 23*

    Non-thermal Hot Dark Matter from Inflaton/Moduli Decay: The Momentum Distribution and Relaxing the Cosmological Mass Bound

    Sukannya Bhattacharya🇮🇳 · Subinoy Das🇮🇳 · Koushik Dutta🇮🇳 · Mayukh Raj Gangopadhyay🇮🇳 · Ratul Mahanta🇮🇳 · Anshuman Maharana🇮🇳

    Decay of the inflaton or moduli which dominated the energy density of the universe at early times leads to a matter to radiation transition epoch. We consider non-thermal sterile dark matter particles produced as decay product during such transitions. The particles have a characteristic energy distribution - that associated with decays taking place in a matter dominated universe evolving to radiation domination. We primarily focus on the case when the particles are hot dark matter, and study their effects on the Cosmic Microwave Background (CMB) and Large Scale Structure (LSS), explicitly taking into account their non-thermal momentum distribution. Our results for CMB angular power and linear matter power spectra reveal interesting features - such as an order of magnitude higher values of hot dark matter mass in comparison to the thermal case being consistent with the present data. We observe that this is related to the fact that $\Delta N_{\mathrm{eff}}$ and the hot DM energy density can be independent of each other unlike the case of thermal or non-resonantly produced sterile hot DM. We also find features in the CMB at low $\ell$ angular power potentially related to supersonic transmission of hot dark matter through the photon-baryon plasma.

    ↳ astro-ph.COhep-phhep-thPRD(2021)·13 citations
24. 24*

    The Stark effect in superfluid ${}^4$He with relative flows

    A.S. Rybalko🇺🇦 · S.P. Rubets🇺🇦 · E.Ya. Rudavskii🇺🇦 · R.V. Golovashchenko🇺🇦 · S.I. Tarapov🇺🇦 · V.N. Derkach🇺🇦 · V.D. Khodusov🇺🇦 · A.S. Naumovets🇺🇦 · A.J. Nurmagambetov🇺🇦

    We conducted series of experiments on observing a Stark-type effect in superfluid ${}^4$He in presence of relative laminar flows of the normal and superfluid components. It is designed a measurement cell which allows us to simultaneously create hydrodynamic flows in the liquid and to carry out high-frequency radio-measurements at external electric field. We used a dielectric disk resonator that made possible to cover a wide frequency range. In our experiments it was registered the spectrum of the dielectric disk resonator modes, as well as narrow lines of absorption of a microwave radiation in He II on its background and in different conditions. We discovered that having in the liquid helium a relative motion of the normal and superfluid fractions in the temperature range of 1.4$÷$2.17 K the narrow line of absorption/radiation is observed in the EM spectrum, the frequency of which - 180 GHz - corresponds to the roton minimum. This line splits in a constant electric field. Note that in a weak electric field the value of splitting depends linearly on the electric field strength, i.e. the linear Stark effect is detected. It is found that with the external electric field increasing both split lines are displaced towards more low frequencies side. The obtained data set could be described by an empirical formula, taking into account as the linear part of the Stark effect, as well as a quadratic addition, related to the polarization part. The data point out on having particles or excitations in the liquid helium with the dipole moment $\sim 10^{-4}$ D, that in four order less of the characteristic dipole moment of polar molecules. The comparison of our findings to values of the electric dipole moment (EDM) of elementary particles and nuclei is also performed. We sum up with brief discussion of extensions of the known theoretical models and possible mechanisms of the EDM production.

    ↳ cond-mat.otherhep-phhep-thquant-ph1 citation
25. 25*

    Cumulants of net-charge distribution from particle-antiparticle sources

    Igor Altsybeev🇷🇺

    It is shown how high-order cumulants of net-charge distribution in hadronic collisions at LHC energies can be expressed via lower-order terms under the assumption that particle-antiparticle pairs are produced in independent local processes. It is argued and tested with HIJING model that this assumption is typically valid for net-proton fluctuations in the case when no critical behaviour is present in the system. Values estimated in such a way can be considered as baselines for direct measurements of high-order net-charge fluctuations in real data.

    ↳ nucl-thhep-phnucl-exActa Phys.Polon.Supp.(2021)·1 citation
26. 26*

    Screening anisotropy via energy-momentum squared gravity: $\Lambda$CDM model with hidden anisotropy

    Ozgur Akarsu🇹🇷 · John D. Barrow🇬🇧 · N. Merve Uzun🇹🇷

    We construct a generalization of the standard $\Lambda$CDM model, wherein we simultaneously replace the spatially flat Robertson-Walker metric with its simplest anisotropic generalization (LRS Bianchi I metric), and couple the cold dark matter to the gravity in accordance with the energy-momentum squared gravity (EMSG) of the form $f(T_{\mu \nu }{T}^{\mu \nu })\propto T_{\mu \nu }{T}^{\mu \nu }$. These two modifications -- namely, two new stiff fluid-like terms of different nature -- can mutually cancel out, i.e., the shear scalar can be screened completely, and reproduce mathematically exactly the same Friedmann equation of the standard $\Lambda$CDM model. This evades the BBN limits on the anisotropy, and thereby provides an opportunity to manipulate the cosmic microwave background quadrupole temperature fluctuation at the desired amount. We further discuss the consequences of the model on the very early times and far future of the Universe. This study presents also an example of that the EMSG of the form $f(T_{\mu \nu }{T}^{\mu \nu })\propto T_{\mu \nu }{T}^{\mu \nu }$, as well as similar type other constructions, is not necessarily relevant only to very early Universe but may even be considered in the context of a major problem of the current cosmology related to the present-day Universe, the so-called $H_0$ problem.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2020)·38 citations
27. 27*

    Cosmic String Interpretation of NANOGrav Pulsar Timing Data

    John Ellis🇬🇧 · Marek Lewicki🇬🇧

    Pulsar timing data used to provide upper limits on a possible stochastic gravitational wave background (SGWB). However, the NANOGrav Collaboration has recently reported strong evidence for a stochastic common-spectrum process, which we interpret as a SGWB in the framework of cosmic strings. The possible NANOGrav signal would correspond to a string tension $G\mu \in (4\times 10^{-11},10^{-10})$ at the 68% confidence level, with a different frequency dependence from supermassive black hole mergers. The SGWB produced by cosmic strings with such values of $G\mu$ would be beyond the reach of LIGO, but could be measured by other planned and proposed detectors such as SKA, LISA, TianQin, AION-1km, AEDGE, Einstein Telescope and Cosmic Explorer.

    ↳ astro-ph.COastro-ph.HEgr-qchep-ph+1PRL(2021)·302 citations
28. 28*

    Has NANOGrav found first evidence for cosmic strings?

    Simone Blasi🇩🇪 · Vedran Brdar🇩🇪 · Kai Schmitz🇨🇭

    The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has recently reported strong evidence for a stochastic common-spectrum process affecting the pulsar timing residuals in its 12.5-year data set. We demonstrate that this process admits an interpretation in terms of a stochastic gravitational-wave background emitted by a cosmic-string network in the early Universe. We study stable Nambu-Goto strings in dependence of their tension $G\mu$ and loop size $\alpha$ and show that the entire viable parameter space will be probed by an array of future experiments.

    ↳ astro-ph.COgr-qchep-phhep-thPRL(2021)·274 citations
29. 29*

    The nonperturbative contribution to asymptotic masses

    Guy D. Moore🇩🇪 · Niels Schlusser🇩🇪

    In gauge theories, charged particles obey modified dispersion due to medium interactions (forward scattering), leading at high energies $E\ge T$ to an asymptotic mass-squared $m_{\infty }^2$. We calculate the infrared part of this mass nonperturbatively for the theory of the strong interactions, QCD, through a lattice treatment of its low-energy effective description, Electrostatic QCD (EQCD). Incorporation of these results into a nonperturbative determination of the effective thermal mass will require a still-incomplete next-to-leading order perturbative matching of this quantity to full QCD.

    ↳ hep-lathep-phPRD(2020)·16 citations
30. 30*

    Extracting the Subhalo Mass Function from Strong Lens Images with Image Segmentation

    Bryan Ostdiek🇺🇸 · Ana Diaz Rivero🇺🇸 · Cora Dvorkin🇺🇸

    Detecting substructure within strongly lensed images is a promising route to shed light on the nature of dark matter. However, it is a challenging task, which traditionally requires detailed lens modeling and source reconstruction, taking weeks to analyze each system. We use machine-learning to circumvent the need for lens and source modeling and develop a neural network to both locate subhalos in an image as well as determine their mass using the technique of image segmentation. The network is trained on images with a single subhalo located near the Einstein ring across a wide range of apparent source magnitudes. The network is then able to resolve subhalos with masses $m\gtrsim 10^{8.5}{M}_{\odot }$. Training in this way allows the network to learn the gravitational lensing of light, and remarkably, it is then able to detect entire populations of substructure, even for locations further away from the Einstein ring than those used in training. Over a wide range of the apparent source magnitude, the false-positive rate is around three false subhalos per 100 images, coming mostly from the lightest detectable subhalo for that signal-to-noise ratio. With good accuracy and a low false-positive rate, counting the number of pixels assigned to each subhalo class over multiple images allows for a measurement of the subhalo mass function (SMF). When measured over three mass bins from $10^9{M}_{\odot }$--$10^{10}{M}_{\odot }$ the SMF slope is recovered with an error of 36% for 50 images, and this improves to 10% for 1000 images with Hubble Space Telescope-like noise.

    ↳ astro-ph.COastro-ph.IMhep-phphysics.data-an+1ApJ(2022)·40 citations
31. 31*

    What becomes of vortices when they grow giant

    Alexander A. Penin🇨🇦 · Quinten Weller🇨🇦

    We discuss vortex solutions of the abelian Higgs model in the limit of large winding number $n$. We suggest a framework where a topological quantum number $n$ is associated with a ratio of dynamical scales and a systematic expansion in inverse powers of $n$ is then derived in the spirit of effective field theory. The general asymptotic form of $giant$ vortices is obtained. For critical coupling the axially symmetric vortices become $integrable$ in the large-$n$ limit and we present the corresponding analytic solution. The method provides simple asymptotic formulae for the vortex shape and parameters with accuracy that can be systematically improved, and can be applied to topological solitons of other models. After including the next-to-leading terms the approximation works remarkably well down to $n=1$.

    ↳ hep-thcond-mat.otherhep-phPRL(2020)·15 citations
32. 32*

    Hydrodynamics formalism with Spin dynamics

    Rajeev Singh🇵🇱

    We review the key steps of the relativistic fluid dynamics formalism with spin degrees of freedom initiated recently. We obtain equations of motion of the expansion of the system from the underlying definitions of quantum kinetic theory for the equilibrium phase space distribution functions. We investigate the dynamics of spin polarization of the system in the Bjorken hydrodynamical background.

    ↳ nucl-thhep-phhep-thActa Phys.Polon.Supp.(2021)·2 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.