Tue·Jun 9, 2020Tuesday·June 9, 2020

1. 01*

   Lambda(1405) as a K-bar N Feshbach resonance in the Skyrme model

   Takashi Ezoe🇯🇵 · Atsushi Hosaka🇯🇵

   We describe the Lambda(1405) hyperon as a Feshbach resonance of a bar-KN quasi-bound state coupled by a decaying channel of pi Sigma in the Skyrme model. A weakly bound bar-KN state is generated in the laboratory frame, while the Sigma hyperon as a strongly bound state of bar-KN in the intrinsic frame. We obtain a coupling of bar-KN and pi Sigma channels by computing a baryon matrix element of the axial current. This coupling enables the decay of the bar-KN bound state to pi-Sigma . It is shown that the Skyrme model supports the Lambda(1405) as a narrow Feshbach resonance.

   hep-phnucl-thPRD(2020)·9 citations
2. 02*

   Vector-axial vector lattice cross section and valence parton distribution in the pion from a chiral quark model

   Wojciech Broniowski🇵🇱 · Enrique Ruiz Arriola🇪🇸

   Within a chiral quark model, we evaluate the good cross section in the Euclidean space in the vector - axial vector channel, proposed recently by Ma and Qiu as means to extract the so far elusive parton distribution functions of the pion from lattice QCD. Our results are remarkably simple at the quark model scale and agree well, after the necessary QCD evolution, with with the most recent lattice calculations at the scale $\mu \sim 2$ GeV for various values of the lattice pion mass. Comparisons are made as functions of the Ioffe time variable. We also comment on the information on the lowest moments in the momentum fraction $x$, generically extractable from such analyses, as well as on the inaccessibility of the $x\to 1$ limit from the present data.

   hep-phhep-latPLB(2020)·4 citations
3. 03*

   Study of the ground state energies of some nuclei using hybrid model

   R. Hussien🇪🇬 · Sh. M. Sewailem🇪🇬 · L. I. Abou-Salem🇪🇬

   The quark-quark QQ interaction as a perturbed term to the nucleon-nucleon interaction NN without any coupling between them is studied in a hybrid model. This model is used to calculate the ground-state energies of 2H1 and 4He2 nuclei. In a semi-relativistic framework, this model is encouraged for light nuclei and the instanton induced interaction by using the QQ potential and the NN interaction for a small scale around the hadron boundaries. This hybrid model depends on two theories, the one-boson exchange potential OBEP and the Cornell-dressed potential CDP for QQ. A small effect of quark-quark interaction is obtained on the values of the ground state energies, around 6.7 for 2H1 and 1.2 for 4He2 by using the considered hybrid model.

   hep-phnucl-thAdv.High Energy Phys.(2021)·0 citations
4. 04*

   Bounds on the triplet fermions in type-III seesaw and implications for collider searches

   Arindam Das🇯🇵 · Sanjoy Mandal🇪🇸

   Type-III seesaw is a simple extension of the Standard Model~(SM) with the SU$(2{)}_{\text{L}}$ triplet fermion with zero hypercharge. It can explain the origin of the tiny neutrino mass and flavor mixing. After the electroweak symmetry breaking the light neutrino mass is generated by the seesaw mechanism which further ensures the mixings between the light neutrino and heavy neutral lepton mass eigenstates. If the triplet fermions are around the electroweak scale having sizable mixings with the SM sector allowed by the correct gauge symmetry, they can be produced at the high energy colliders leaving a variety of characteristic signatures. Based on a simple and concrete realizations of the model we employ a general parametrization for the neutrino Dirac mass matrix and perform a parameter scan to identify the allowed regions satisfying the experimental constraints from the neutrino oscillation data, the electroweak precision measurements and the lepton-flavor violating processes, respectively considering the normal and inverted neutrino mass hierarchies. These parameter regions can be probed at the different collider experiments.

   hep-phhep-exNPB(2021)·47 citations
5. 05*

   MiNNLO${}_{\mathrm{PS}}$: Optimizing $2\to 1$ hadronic processes

   Pier Francesco Monni🇨🇭 · Emanuele Re🇫🇷 · Marius Wiesemann🇩🇪

   We consider the MiNNLO${}_{\mathrm{PS}}$ method to consistently combine next-to-next-to-leading order (NNLO) QCD calculations with parton-shower simulations. We identify the main sources of differences between MiNNLO${}_{\mathrm{PS}}$ and fixed-order NNLO predictions for inclusive observables due to corrections beyond NNLO accuracy and present simple prescriptions to either reduce or remove them. Refined predictions are presented for Higgs, charged- and neutral-current Drell Yan production. The agreement with fixed-order NNLO calculations is considerably improved for inclusive observables and scale uncertainties are reduced. The codes are released within the POWHEG-BOX.

   hep-phhep-exEPJC(2020)·147 citations
6. 06*

   MasterTwo: A Mathematica Package for the Automated Calculation of Two Loop Diagrams in the Standard Model and Beyond

   Sabine Schilling🇨🇭

   The calculation of rare loop decays in the Standard Model of Particle Physics and its extensions is an extremely tedious work. The Mathematica package MasterTwo facilitates this task. It automatically calculates all loop integrals reducible to scalar integrals depending on up to two different masses independent of external momenta. MasterTwo consists of two sub packages, Fermions and Integrals. Whereas Fermions covers the standard Dirac Algebra, Integrals performs the Taylor expansion, partial fraction, tensor reduction and the integration of the thus achieved scalar integrals. The package works completely inside Mathematica and can be easily customised for both educational and research purposes.

   hep-ph0 citations
7. 07*

   Thermodynamic and Transport Properties of Matter Formed in $pp$, $p$-Pb, Xe-Xe and Pb-Pb Collisions at the Large Hadron Collider using Color String Percolation Model

   Dushmanta Sahu🇮🇳 · Raghunath Sahoo🇮🇳

   To have a better understanding of the matter formed in ultra-relativistic collisions, using the Color String Percolation Model (CSPM), we have estimated initial energy density, mean free path, squared speed of sound, shear viscosity to entropy density ratio ($\eta /s$), bulk viscosity to entropy density ratio and bulk modulus for $pp$, $p$-Pb, Xe-Xe and Pb-Pb collisions at the Large Hadron Collider (LHC). These observables are studied as a function of final state charged particle multiplicity density and initial state percolation temperature. The results from this work are compared with the results from well known QCD models and with the transport properties of matter found in day-to-day life. These observables allow us to conclude an array of important findings about the matter formed in high energy collisions at the LHC. This work gives a threshold of charged particle multiplicity $⟨d{N}_{ch}/d\eta ⟩\simeq$ 20, after which there are indications of change in the dynamics of the systems. The critical initial energy density and temperature as estimated by lattice QCD, are observed to be achieved for events with final state multiplicity $⟨d{N}_{ch}/d\eta ⟩\ge$ 20. In addition, for these high-multiplicity events, the estimated $\eta /s$ are comparable with that is observed for heavy-ion collisions, which is an indication of a strongly coupled Quark Gluon Plasma. This makes LHC high-multiplicity $pp$ collision events as probable candidates for the search of QGP droplets.

   hep-phhep-exnucl-exnucl-thJ.Phys.G(2021)·23 citations
8. 08*

   On the new LHCb angular analysis of $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$: Hadronic effects or New Physics?

   T. Hurth🇩🇪 · F. Mahmoudi🇫🇷 · S. Neshatpour🇫🇷

   The new angular analysis of the decay $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ recently presented by the LHCb Collaboration still indicates some tensions with the Standard Model predictions. There are several ongoing analyses to solve the problem of separating hadronic and New Physics effects in this decay, but the significance of the observed tensions in the angular observables in $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ is still dependent on a theory guesstimate of the hadronic contributions to these decays. Using the new data from LHCb we offer two tests which make a statistical comparison to determine whether the most favoured explanation of the anomalies is New Physics or underestimated hadronic effects. We then analyse the usefulness of these tests in two future scenarios. Finally, we update our global fits to all available $b\to s$ data and discuss the impact of the new LHCb measurements.

   hep-phPRD(2020)·56 citations
9. 09*

   Probing the sensitivity to leptonic ${\delta }_{CP}$ in presence of invisible decay of ${\nu }_3$ using atmospheric neutrinos

   Lakshmi.S.Mohan

   One of the main neutrino oscillation parameters whose value has not been determined very precisely is the leptonic ${\delta }_{CP}$ phase. Since neutrinos have a tiny but finite mass they can undergo decay both visibly and invisibly. The effect of invisible decay of the third mass eigen state ${\nu }_3$ on the sensitivity to ${\delta }_{CP}$ is analysed here using atmospheric neutrino and anti-neutrino events. Effects of detector resolutions and systematic uncertainties are studied to identify the optimum resolutions and efficiencies required by a detector to obtain a significant sensitivity even in presence of decay.

   hep-phJ.Phys.G(2020)·4 citations
10. 10*

    Non-linear Breit-Wheeler process with linearly polarized beams

    Alexander I. Titov🇷🇺 · Burkhard Kampfer🇩🇪

    We study the non-linear Breit-Wheeler process ${\vec{\gamma }}^{\prime }+\vec{L}\to e^{+}+e^{-}$ in the interaction of linearly polarized probe photons (${\vec{\gamma }}^{\prime }$) with a linearly polarized laser beam ($\vec{L}$). In particular, we consider the asymmetry of the total cross section and the azimuthal electron distributions when the polarizations of the photon and laser beams in the initial state are mutually perpendicular or parallel. Considering intense laser beams and the strong field asymptotic we explore essentially the multi-photon dynamics. The asymmetry exhibits some non-monotonic behavior depending on initial kinematic conditions; it depends sensitively on the laser pulse duration. Our results provide additional knowledge for studying non-linear multi-photon effects in quantum electrodynamics and may be used in planning experiments in upcoming laser facilities.

    hep-phEur.Phys.J.D(2020)·29 citations
11. 11*

    Novel sum rules for the three-point sector of QCD

    A. C. Aguilar🇧🇷 · M. N. Ferreira🇧🇷 · J. Papavassiliou🇪🇸

    For special kinematic configurations involving a single momentum scale, certain standard relations, originating from the Slavnov-Taylor identities of the theory, may be interpreted as ordinary differential equations for the ``kinetic term'' of the gluon propagator. The exact solutions of these equations exhibit poles at the origin, which are incompatible with the physical answer, known to diverge only logarithmically; their elimination hinges on the validity of two integral conditions that we denominate ``asymmetric'' and ``symmetric'' sum rules, depending on the kinematics employed in their derivation. The corresponding integrands contain components of the three-gluon vertex and the ghost-gluon kernel, whose dynamics are constrained when the sum rules are imposed. For the numerical treatment we single out the asymmetric sum rule, given that its support stems predominantly from low and intermediate energy regimes of the defining integral, which are physically more interesting. Adopting a combined approach based on Schwinger-Dyson equations and lattice simulations, we demonstrate how the sum rule clearly favors the suppression of an effective form factor entering in the definition of its kernel. The results of the present work offer an additional vantage point into the rich and complex structure of the three-point sector of QCD.

    hep-phhep-lathep-thEPJC(2020)·16 citations
12. 12*

    Discriminating the HTM and MLRSM models in collider studies via doubly charged Higgs boson pair production and the subsequent leptonic decays

    Janusz Gluza🇵🇱 · Magdalena Kordiaczynska🇵🇱 · Tripurari Srivastava🇮🇳

    We present a case study for the doubly charged Higgs bosons $H^{\pm \pm }$ pair production in $e^{+}{e}^{-}$ and $pp$ colliders with their subsequent decays to four charged leptons. We consider the Higgs Triplet Model (HTM) not restricted by the custodial symmetry and the Minimal Left-Right Symmetric Model (MLRSM). The models include scalar triplets with different complexity of scalar potentials and, due to experimental restrictions, completely different scales of non-standard triplet vacuum expectation values. In both models, a doubly charged Higgs boson $H^{\pm \pm }$ can acquire a mass of hundreds of gigaelectronvolts, which can be probed at HL-LHC, future $e^{+}{e}^{-}$, and hadron colliders. We take into account a comprehensive set of constraints on the parameters of both models coming from neutrino oscillations, LHC, $e^{+}{e}^{-}$ and low-energy lepton flavour violating data and assume the same mass of $H^{\pm \pm }$. Our finding is that the $H^{\pm \pm }$ pair production in lepton and hadron colliders is comparable in both models, though more pronounced in MLRSM. We show that the decay branching ratios can be different within both models, leading to distinguishable four lepton signals and that the strongest are $4\mu$ events yielded by MLRSM. Typically we find that MLRSM signals are one order of magnitude larger that in HTM. For example, the $pp\to 4\mu$ MLRSM signal for 1 TeV $H^{\pm \pm }$ mass results in a clearly detectable significance of $S\simeq 11$ for HL-LHC and $S\simeq 290$ for FCC-hh. Finally we provide quantitative predictions for the dilepton invariant mass distributions and lepton separations which help to identify non-standard signals.

    hep-phhep-exCPC(2021)·11 citations
13. 13*

    Searching in the dark: the hunt for the dark photon

    Alessandra Filippi🇮🇹 · Marzio De Napoli🇮🇹

    The existence of Dark Matter (DM) is a well established fact since many decades, thanks to the observation of the effects of its gravitational interaction with the ordinary matter in the Universe. However, our knowledge of the Dark Matter features is still rather scarce. Indeed, one of the biggest quests in fundamental science today is the investigation of Dark Matter nature, from its origin to its composition, and the way its constituents interact with the ordinary matter, apart from gravity. Huge and ambitious efforts have been spent in the last years into its identification, concentrating especially on the search of viable Weakly Interacting Massive Particle candidates. However, no positive results have been achieved so far along this direction. On the other hand, many fascinating new ideas and models for its interpretation have been blooming: among them, an intriguing hypothesis is that the Dark Matter constituents could be neutral under Standard Model interactions, but they could interact through a new, still unknown, force under a "hidden" charge. This new hidden symmetry would be mediated by a massive gauge boson, the dark photon, which is expected to couple to the Standard Model via a kinetic mixing. The search for such a massive mediator has been pursued with large enthusiasm and dedication in the latest years, as its observation could be within the reach of many already existing experimental facilities, both based on accelerators

    hep-phRev.Phys.(2020)·95 citations
14. 14*

    Lorentz Group Equivariant Neural Network for Particle Physics

    Alexander Bogatskiy🇺🇸 · Brandon Anderson🇺🇸 · Jan T. Offermann🇺🇸 · Marwah Roussi🇺🇸 · David W. Miller🇺🇸 · Risi Kondor🇺🇸

    We present a neural network architecture that is fully equivariant with respect to transformations under the Lorentz group, a fundamental symmetry of space and time in physics. The architecture is based on the theory of the finite-dimensional representations of the Lorentz group and the equivariant nonlinearity involves the tensor product. For classification tasks in particle physics, we demonstrate that such an equivariant architecture leads to drastically simpler models that have relatively few learnable parameters and are much more physically interpretable than leading approaches that use CNNs and point cloud approaches. The competitive performance of the network is demonstrated on a public classification dataset [27] for tagging top quark decays given energy-momenta of jet constituents produced in proton-proton collisions.

    hep-phcs.LGhep-exphysics.comp-ph+173 citations
15. 15*

    Predictions for Axion Couplings from ALP Cogenesis

    Raymond T. Co🇺🇸 · Lawrence J. Hall🇺🇸 · Keisuke Harigaya🇺🇸

    Adding an axion-like particle (ALP) to the Standard Model, with a field velocity in the early universe, simultaneously explains the observed baryon and dark matter densities. This requires one or more couplings between the ALP and photons, nucleons, and/or electrons that are predicted as functions of the ALP mass. These predictions arise because the ratio of dark matter to baryon densities is independent of the ALP field velocity, allowing a correlation between the ALP mass, $m_a$, and decay constant, $f_a$. The predicted couplings are orders of magnitude larger than those for the QCD axion and for dark matter from the conventional ALP misalignment mechanism. As a result, this scheme, ALP cogenesis, is within reach of future experimental ALP searches from the lab and stellar objects, and for dark matter.

    hep-phastro-ph.COhep-exJHEP(2021)·124 citations
16. 16*

    BBN constraints on universally-coupled ultralight scalar dark matter

    Sergey Sibiryakov🇨🇭 · Philip Sørensen🇩🇪 · Tien-Tien Yu🇺🇸

    Ultralight scalar dark matter can interact with all massive Standard Model particles through a universal coupling. Such a coupling modifies the Standard Model particle masses and affects the dynamics of Big Bang Nucleosynthesis. We model the cosmological evolution of the dark matter, taking into account the modifications of the scalar mass by the environment as well as the full dynamics of Big Bang Nucleosynthesis. We find that precision measurements of the helium-4 abundance set stringent constraints on the available parameter space, and that these constraints are strongly affected by both the dark matter environmental mass and the dynamics of the neutron freeze-out. Furthermore, we perform the analysis in both the Einstein and Jordan frames, the latter of which allows us to implement the model into numerical Big Bang Nucleosynthesis codes and analyze additional light elements. The numerical analysis shows that the constraint from helium-4 dominates over deuterium, and that the effect on lithium is insufficient to solve the lithium problem. Comparing to several other probes, we find that Big Bang Nucleosynthesis sets the strongest constraints for the majority of the parameter space.

    hep-phastro-ph.COJHEP(2020)·41 citations
17. 17*

    The anomalous magnetic moment of the muon in the Standard Model

    T. Aoyama🇯🇵 · N. Asmussen🇬🇧 · M. Benayoun🇫🇷 · J. Bijnens🇸🇪 · T. Blum🇺🇸 · M. Bruno🇨🇭 · I. Caprini🇷🇴 · C. M. Carloni Calame🇮🇹 · M. Cè🇨🇭 · G. Colangelo🇨🇭 · F. Curciarello🇮🇹 · H. Czyż🇵🇱 and 120 other authors

    We review the present status of the Standard Model calculation of the anomalous magnetic moment of the muon. This is performed in a perturbative expansion in the fine-structure constant $\alpha$ and is broken down into pure QED, electroweak, and hadronic contributions. The pure QED contribution is by far the largest and has been evaluated up to and including $\mathcal{O}({\alpha }^5)$ with negligible numerical uncertainty. The electroweak contribution is suppressed by $(m_{\mu }/M_W{)}^2$ and only shows up at the level of the seventh significant digit. It has been evaluated up to two loops and is known to better than one percent. Hadronic contributions are the most difficult to calculate and are responsible for almost all of the theoretical uncertainty. The leading hadronic contribution appears at $\mathcal{O}({\alpha }^2)$ and is due to hadronic vacuum polarization, whereas at $\mathcal{O}({\alpha }^3)$ the hadronic light-by-light scattering contribution appears. Given the low characteristic scale of this observable, these contributions have to be calculated with nonperturbative methods, in particular, dispersion relations and the lattice approach to QCD. The largest part of this review is dedicated to a detailed account of recent efforts to improve the calculation of these two contributions with either a data-driven, dispersive approach, or a first-principle, lattice-QCD approach. The final result reads $a_{\mu }^{\text{SM}}=116591810(43)\times 10^{-11}$ and is smaller than the Brookhaven measurement by 3.7$\sigma$. The experimental uncertainty will soon be reduced by up to a factor four by the new experiment currently running at Fermilab, and also by the future J-PARC experiment. This and the prospects to further reduce the theoretical uncertainty in the near future-which are also discussed here-make this quantity one of the most promising places to look for evidence of new physics.

    hep-phhep-exhep-latnucl-ex+1Phys.Rept.(2020)·1886 citations
18. 18*

    New physics in $B$ meson mixing: future sensitivity and limitations

    J. Charles🇫🇷 · S. Descotes-Genon🇫🇷 · Z. Ligeti🇺🇸 · S. Monteil🇫🇷 · M. Papucci🇺🇸 · K. Trabelsi🇫🇷 · L. Vale Silva🇪🇸

    The mixing of neutral mesons is sensitive to some of the highest scales probed in laboratory experiments. In light of the planned LHCb Upgrade II, a possible upgrade of Belle II, and the broad interest in flavor physics in the tera-$Z$ phase of the proposed FCC-ee program, we study constraints on new physics contributions to $B_d$ and $B_s$ mixings which can be obtained in these benchmark scenarios. We explore the limitations of this program, and identify the measurement of $|V_{cb}|$ as one of the key ingredients in which progress beyond current expectations is necessary to maximize future sensitivity. We speculate on possible solutions to this bottleneck. Given the current tension with the standard model (SM) in semileptonic $B$ decays, we explore how its resolution may impact the search for new physics in mixing. Even if new physics has the same CKM and loop suppressions of flavor changing processes as the SM, the sensitivity will reach 2 TeV, and it can be much higher if any SM suppressions are lifted. We illustrate the discovery potential of this program.

    hep-phhep-exPRD(2020)·75 citations
19. 19*

    Probing a new decay of vector-like top partner mediated by heavy Majorana neutrino via single production

    Hang Zhou🇨🇳 · Ning Liu🇨🇳

    Models beyond the Standard Model have been proposed to simultaneously solve the problems of naturalness and neutrino mass, in which heavy Majorana neutrinos and vector-like top partners are usually predicted. A new decay channel of the top partner mediated by the heavy Majorana neutrino can thus appear: $T\to b{W}^{+}\to b{\ell }^{+}{\ell }^{+}q\overline{q^{\prime }}$. We study in this paper the observability of this decay process through single production of the top partner at the 14 TeV LHC: $pp\to T/\bar{T}$+jets$\to b/\bar{b}+{\mu }^{\pm }{\mu }^{\pm }$+jets. $2\sigma$ exclusion bounds on the top partner mass and mixing parameters are given by Monte-Carlo simulation, which surpass those from the search through VLT pair production in the mass range of $m_T>1.3$ TeV.

    hep-phPRD(2020)·9 citations
20. 20*

    ${\gamma }^{\ast }\gamma$ and ${\gamma }^{\ast }p$ scattering in IHQCD

    Artur Amorim🇵🇹 · Miguel S. Costa🇵🇹

    We perform joint fits using measurements of the proton structure functions $F_2(x,Q^2)$ and $F_L(x,Q^2)$, of the photon structure function $F_2^{\gamma }(x,Q^2)$ and of the total cross-sections $\sigma \left(\gamma p\to X\right)$ and $\sigma \left(\gamma \gamma \to X\right)$. The data is gathered from several sources including HERA and LEP. The kinematical range considered is wide with a photon virtuality $Q^2\le 400{\mathrm{GeV}}^2$, Bjorken variable $x<0.01$ and $\sqrt{s}>4\mathrm{GeV}$. This is done by considering a $U\left(1\right)$ vector gauge field minimally coupled to the graviton Regge trajectory in improved holographic QCD. We find good agreement with the data for a joint fit of $F_2^{\gamma }$ and $\sigma \left(\gamma \gamma \to X\right)$ with a ${\chi }_{d.o.f.}^2=1.07$. For a joint fit of $F_2$, $F_L$ and $\sigma \left(\gamma p\to X\right)$ we find ${\chi }_{d.o.f.}^2=1.40$. A joint fit of all observables for both processes ${\gamma }^{\ast }\gamma$ and ${\gamma }^{\ast }p$ gives a ${\chi }_{d.o.f.}^2=1.38$. The gravitational couplings of the $U\left(1\right)$ vector gauge field and of the proton with the Reggeons of the graviton Regge trajectory are given as an output of the fitting procedure. An approximate relation between the structure functions, valid at NLO QCD, is used to estimate the parton distribution function of the gluon inside the proton.

    hep-phhep-th0 citations
21. 21*

    Two-current correlations in the pion in the Nambu and Jona-Lasinio model

    A.~Courtoy🇲🇽 · Santiago Noguera🇪🇸 · Sergio Scopetta🇮🇹

    We present an analysis of two-current correlations for the pion in the Nambu--Jona-Lasinio model, with Pauli--Villars regularization. We provide explicit expressions in momentum space for two-current correlations corresponding to the zeroth component of the vector Dirac bilinear in the quark vertices, which has been evaluated on the lattice. The numerical results show a remarkable qualitative agreement with recent lattice data. The factorization approximation into one-body currents is discussed.

    hep-phnucl-thEPJC(2020)·6 citations
22. 22*

    Constraints on Primordial Black Holes From Big Bang Nucleosynthesis Revisited

    Celeste Keith🇺🇸 · Dan Hooper🇺🇸 · Nikita Blinov🇺🇸 · Samuel D. McDermott🇺🇸

    As space expands, the energy density in black holes increases relative to that of radiation, providing us with motivation to consider scenarios in which the early universe contained a significant abundance of such objects. In this study, we revisit the constraints on primordial black holes derived from measurements of the light element abundances. Black holes and their Hawking evaporation products can impact the era of Big Bang Nucleosynthesis (BBN) by altering the rate of expansion at the time of neutron-proton freeze-out, as well as by radiating mesons which can convert protons into neutrons and vice versa. Such black holes can thus enhance the primordial neutron-to-proton ratio, and increase the amount of helium that is ultimately produced. Additionally, the products of Hawking evaporation can break up helium nuclei, which both reduces the helium abundance and increases the abundance of primordial deuterium. Building upon previous work, we make use of modern deuterium and helium measurements to derive stringent constraints on black holes which evaporate in $t_{\mathrm{evap}}\sim 10^{-1}$ s to $\sim 10^{13}$ s (corresponding to $M\sim 6\times 10^8$ g to $\sim 2\times 10^{13}$ g, assuming Standard Model particle content). We also consider how physics beyond the Standard Model could impact these constraints. Due to the gravitational nature of Hawking evaporation, the rate at which a black hole evaporates, and the types of particles that are produced through this process, depend on the complete particle spectrum. Within this context, we discuss scenarios which feature a large number of decoupled degrees-of-freedom (\ie~large hidden sectors), as well as models of TeV-scale supersymmetry.

    ↳ astro-ph.COastro-ph.HEhep-phPRD(2020)·100 citations
23. 23*

    Studying the parameters of the extended $\sigma$-$\omega$ model for neutron star matter

    David Alvarez-Castillo🇵🇱 · Alexander Ayriyan🇷🇺 · Gergely Gábor Barnaföldi🇭🇺 · Hovik Grigorian🇷🇺 · Péter Pósfay🇭🇺

    In this work we study the parameters of the extended $\sigma$-$\omega$ model for neutron star matter by a Bayesian analysis on state-of-the-art multi-messenger astronomy observations, namely mass, radius and tidal deformabilities. We have considered three parameters of the model, the Landau mass $m_L$, the nuclear compressibility $K_0$, and the value of the symmetry energy $S_0$, all at saturation density $n_0$. As a result, we are able to estimate the values of the Landau mass of f $m_L=739\pm 17$ MeV, whereas the values of $K_0$ and $S_0$ fall within already known empirical values. Furthermore, for neutron stars we find the most probable value of 13 km $<R_{1.4}<$ 13.5 km and the upper mass limit of $M_{max}\approx 2.2$ M${}_{\odot }$.

    ↳ astro-ph.HEhep-phnucl-thEur.Phys.J.ST(2020)·13 citations
24. 24*

    Cosmological constraints on late-universe decaying dark matter as a solution to the $H_0$ tension

    Steven J. Clark🇺🇸 · Kyriakos Vattis🇺🇸 · Savvas M. Koushiappas🇺🇸

    It has been suggested that late-universe dark matter decays can alleviate the tension between measurements of $H_0$ in the local universe and its value inferred from cosmic microwave background fluctuations. It has been suggested that decaying dark matter can potentially account for this discrepancy as it reshuffles the energy density between matter and radiation and as a result allows dark energy to become dominant at earlier times. In this work, we show that the low multipole amplitude of the cosmic microwave background anisotropy power spectrum severely constrains the feasibility of late-time decays as a solution to the $H_0$ tension.

    ↳ astro-ph.COhep-phPRD(2021)·84 citations
25. 25*

    Constraining the onset density of the hadron-quark phase transition with gravitational-wave observations

    Sebastian Blacker🇩🇪 · Niels-Uwe F. Bastian🇵🇱 · Andreas Bauswein🇩🇪 · David B. Blaschke🇵🇱 · Tobias Fischer🇵🇱 · Micaela Oertel🇫🇷 · Theodoros Soultanis🇩🇪 · Stefan Typel🇩🇪

    We study the possible occurrence of the hadron-quark phase transition (PT) during the merging of neutron star binaries by hydrodynamical simulations employing a set of temperature dependent hybrid equations of state (EoSs). Following previous work we describe an unambiguous and measurable signature of deconfined quark matter in the gravitational-wave (GW) signal of neutron star binary mergers including equal-mass and unequal-mass systems of different total binary mass. The softening of the EoS by the PT at higher densities, i.e. after merging, leads to a characteristic increase of the dominant postmerger GW frequency f_peak relative to the tidal deformability Lambda inferred during the premerger inspiral phase. Hence, measuring such an increase of the postmerger frequency provides evidence for the presence of a strong PT. If the postmerger frequency and the tidal deformability are compatible with results from purely baryonic EoS models yielding very tight relations between f_peak and Lambda, a strong PT can be excluded up to a certain density. We find tight correlations of f_peak and Lambda with the maximum density during the early postmerger remnant evolution. These GW observables thus inform about the density regime which is probed by the remnant and its GW emission. Exploiting such relations we devise a directly applicable, concrete procedure to constrain the onset density of the QCD PT from future GW measurements. We point out two interesting scenarios: if no indications for a PT are inferred from a GW detection, our procedure yields a lower limit on the onset density of the hadron quark PT. On the contrary, if a merger event reveals evidence for the occurrence of deconfined quark matter, the inferred GW parameters set an upper limit on the PT onset density. (abridged)

    ↳ astro-ph.HEhep-phnucl-thPRD(2020)·119 citations
26. 26*

    Search for CP-violating nuclear magnetic quadrupole moment using the LuOH${}^{+}$ cation

    D.E. Maison🇷🇺 · L.V. Skripnikov🇷🇺 · V.V. Flambaum🇦🇺 · M. Grau🇨🇭

    The CP-violating interaction of the nuclear magnetic quadrupole moment (MQM) of the ${}^{175}$Lu nucleus with electrons in the molecular cation LuOH${}^{+}$ is studied. The resulting effect is expressed in terms of CP-odd parameters, such as quantum chromodynamics angle $\bar{\theta }$, quark electric dipole moment (EDM) and chromo-EDM. For this we have performed a calculation of the nuclear MQM as well as the molecular constant that characterises the interaction of this MQM of ${}^{175}$Lu with electrons. Additionally, we predict the hyperfine structure constants for the ground electronic state of LuOH${}^{+}$. We conclude that LuOH${}^{+}$ is a promising system to measure the nuclear MQM.

    ↳ physics.atom-phhep-phnucl-thJ.Chem.Phys.(2020)·23 citations
27. 27*

    Radiative pion photoproduction in covariant chiral perturbation theory

    J. Rijneveen🇩🇪 · N. Rijneveen🇩🇪 · H. Krebs🇩🇪 · A. M. Gasparyan🇩🇪 · E. Epelbaum🇩🇪

    We present a calculation of radiative pion photoproduction in the framework of covariant chiral perturbation theory with explicit $\Delta (1232)$ degrees of freedom. The analysis is performed employing the small scale expansion scheme adjusted for the $\Delta$ region. Depending on the channel, we include contributions up to next-to-next-to-leading order. We fit the available experimental data for the reaction $\gamma p\to \gamma p{\pi }^0$ and extract the value of the ${\Delta }^{+}$ magnetic moment. Errors from the truncation of the small scale expansion are estimated using the Bayesian approach. We compare our results both with the previous studies within the $\delta$-expansion scheme and with the $\Delta$-less theory. We also give predictions for radiative charged-pion photoproduction.

    ↳ nucl-thhep-phPRC(2021)·5 citations
28. 28*

    Response to a comment on Dessert et al. "The dark matter interpretation of the 3.5 keV line is inconsistent with blank-sky observations"

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

    The dark matter explanation of the 3.5 keV line is strongly disfavored by our work in Dessert et al. 2020. Boyarsky et al. 2020 questions that conclusion: modeling additional background lines is claimed to weaken the limit sufficiently to re-allow a dark matter interpretation. We respond as follows. 1) A more conservative limit is obtained by modeling additional lines; this point appeared in its entirety in our work in Dessert et al., though we also showed that the inclusion of such lines is not necessary. 2) Despite suggestions in Boyarsky et al., even the more conservative limits strongly disfavor a decaying dark matter origin of the 3.5 keV line.

    ↳ astro-ph.COastro-ph.HEhep-phPhys.Dark Univ.(2020)·25 citations
29. 29*

    Photohadronic model for the neutrino and $\gamma$-ray emission from TXS 0506+056

    Sarira Sahu🇲🇽 · Carlos Eduardo Lopez Fortin🇲🇽 · Shigehiro Nagataki🇯🇵

    The detection of a high energy muon neutrino on 22 September 2017 by IceCube neutrino detector coincides with the multiwavelength flaring from the BL Lac object TXS 0506+056, most likely confirming AGN as a source of high energy cosmic rays and neutrinos. Using the photohadronic model, we have explained the very high energy $\gamma$-rays observed by MAGIC telescopes few days after the neutrino event and extend the model to calculate the neutrino flux at different windows consistent with the flaring period of TXS 0506+056 and compared with the IceCube and MAGIC estimates. We also use this model to estimate the neutrino flux from the flaring of FSRQ PKS B1424-418 which is believed to be associated with the 2 PeV neutrino event observed by IceCube.

    ↳ astro-ph.HEhep-phApJ(2020)·8 citations
30. 30*

    Linked vortices as baryons in the miscible BEC-Skyrme model

    Sven Bjarke Gudnason🇨🇳 · Muneto Nitta🇯🇵

    We introduce a variation of the Bose-Einstein condensate(BEC)-Skyrme model, with an altered potential for miscible BECs that gives rise to two physical vortex strings. In the ground state of each topological sector, the vortices are linked exactly $B$ times, due to a recently formulated theorem, with $B$ being the baryon number of the solution. The model also possesses metastable states, where the vortices are degenerate and do not lend the interpretation of the baryon number as the linking number of the vortices.

    ↳ hep-thcond-mat.quant-gashep-phPRD(2020)·5 citations
31. 31*

    The TeV gamma-ray luminosity of the Milky-Way and the contribution of H.E.S.S. unresolved sources to VHE diffuse emission

    Maddalena Cataldo🇮🇹 · Giulia Pagliaroli🇮🇹 · Vittoria Vecchiotti🇮🇹 · Francesco Lorenzo Villante🇮🇹

    H.E.S.S. has recently completed a systematic survey of the Galactic plane in the TeV energy domain. We analyze the flux, latitude and longitude distributions of $\gamma -$ray sources observed by H.E.S.S. in order to infer the properties of Galactic TeV source population. We show that the total Milky-Way luminosity in the 1-100 TeV energy range is $L_{\mathrm{MW}}=1.7_{-0.4}^{+0.5}\times 10^{37}\mathrm{ergs}{\sec }^{-1}$. Evaluating the cumulative flux expected at Earth by the considered population, we show that H.E.S.S. unresolved sources provide a relevant contribution to the diffuse Galactic emission. Finally, in the hypothesis that the majority of bright sources detected by H.E.S.S. are powered by pulsar activity, like e.g. Pulsar Wind Nebulae or TeV halos, we estimate the main properties of the pulsar population.

    ↳ astro-ph.HEhep-phApJ(2020)·28 citations
32. 32*

    Far From Equilibrium Hydrodynamics and the Beam Energy Scan

    Travis Dore🇺🇸 · Emma McLaughlin🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸

    The existence of hydrodynamic attractors in rapidly expanding relativistic systems has shed light on the success of relativistic hydrodynamics in describing heavy-ion collisions at zero chemical potential. As the search for the QCD critical point continues, it is important to investigate how out of equilibrium effects influence the trajectories on the QCD phase diagram. In this proceedings, we study a Bjorken expanding hydrodynamic system based on DMNR equations of motion with initial out of equilibrium effects and finite chemical potential in a system with a critical point. We find that the initial conditions are not unique for a specific freeze-out point, but rather the system can evolve to the same final state freeze-out point with a wide range of initial baryon chemical potential, ${\mu }_B$. For the same initial energy density and baryon density, depending on how far out of equilibrium the system begins, the initial ${\mu }_B$ can vary by $\Delta {\mu }_B\sim 350$ MeV. Our results indicate that knowledge of the out-of-equilibrium effects in the initial state provide vital information that influences the search for the QCD critical point.

    ↳ nucl-thhep-phnucl-exJ.Phys.Conf.Ser.(2020)·9 citations
33. 33*

    Charge separation measurements in $p$($d$)+Au and Au+Au collisions; implications for the chiral magnetic effect

    STAR Collaboration

    Charge separation ($\Delta S$) measurements, obtained relative to the $2^{\mathrm{nd}}$-order (${\Psi }_2$) and $3^{\mathrm{rd}}$-order (${\Psi }_3$) event planes with a new charge-sensitive correlator $R_{{\Psi }_m}(\Delta S)$, are presented for $p$($d$)+Au and Au+Au collisions at $\sqrt{s_{NN}}=200$~GeV. The correlator, which is sensitive to the hypothesized Chiral Magnetic Effect (CME), show the expected patterns of background-driven charge separation for the measurements relative to ${\Psi }_3$ and those relative to ${\Psi }_2$ for the $p$($d$)+Au systems. By contrast, the Au+Au measurements relative to ${\Psi }_2$, show event-shape-independent $R_{{\Psi }_2}(\Delta S)$ distributions consistent with a CME-driven charge separation, quantified by widths having an inverse relationship to the Fourier dipole coefficient ${\tilde{a}}_1$, which evaluates the CME. The extracted values of these widths and their dependencies on centrality and event-shape give new constraints for possible CME-driven charge separation in relativistic heavy-ion collisions.

    ↳ nucl-exhep-exhep-phnucl-th14 citations
34. 34*

    Gravitational waves of a first-order QCD phase transition at finite coupling from holography

    M. Ahmadvand🇮🇷 · K. Bitaghsir Fadafan🇮🇷 · S. Rezapour🇮🇷

    We consider a holographic study of coupling dependent gravitational waves produced by the cosmic first order QCD phase transition at finite baryochemical potential. In the dual description, the first-order QCD phase transition corresponds to the first-order Hawking-Page phase transition in Gauss-Bonnet gravity. At intermediate coupling, we obtain key quantities characterizing the gravitational wave energy density spectrum. We then find that the gravitational waves might be detected for sufficiently large Gauss-Bonnet coupling, while sound waves play an important role in the spectrum. We also consider a supercooling scenario during the QCD phase transition and show that the gravitational waves generated during this period can be detected by pulsar timing array experiments.

    ↳ hep-thgr-qchep-phAnnals Phys.(2022)·17 citations
35. 35*

    Brans-Dicke cosmology with a $\Lambda$- term: a possible solution to $\Lambda$CDM tensions

    Joan Sola🇪🇸 · Adria Gomez-Valent🇩🇪 · Javier de Cruz Perez🇪🇸 · Cristian Moreno-Pulido🇪🇸

    We present a full-fledged analysis of Brans-Dicke cosmology with a cosmological constant and cold dark matter (BD-$\Lambda$CDM for short). We extend the scenarios where the current cosmological value of the BD-field is restricted by the local astrophysical domain to scenarios where that value is fixed only by the cosmological observations, which should be more natural in view of the possible existence of local screening mechanims. Our analysis includes both the background and perturbations equations in different gauges. We find that the BD-$\Lambda$CDM is favored by the overall cosmological data as compared to the concordance GR-$\Lambda$CDM model, namely data on distant supernovae, cosmic chronometers, local measurements of the Hubble parameter, baryonic acoustic oscillations, Large-Scale Structure formation and the cosmic microwave background under full Planck 2018 CMB likelihood. We also test the impact of Strong and Weak-Lensing data on our results, which can be significant. We find that the BD-$\Lambda$CDM can mimic effective quintessence with a significance of about $3-3.5\sigma$ c.l. (depending on the lensing datasets). The fact that the BD-$\Lambda$CDM behaves effectively as a Running Vacuum Model (RVM) when viewed from the GR perspective helps to alleviate some of the existing tensions with the data, such as the ${\sigma }_8$ excess predicted by GR-$\Lambda$CDM. On the other hand, the BD-$\Lambda$CDM model has a crucial bearing on the acute $H_0$-tension with the local measurements, which is rendered virtually harmless owing to the small increase of the effective value of the gravitational constant with the expansion. The simultaneous alleviation of the two tensions is a most remarkable feature of BD-gravity with a cosmological constant in the light of the current observations, and hence goes in support of BD-$\Lambda$CDM against GR-$\Lambda$CDM

    ↳ astro-ph.COgr-qchep-phhep-thClass.Quant.Grav.(2020)·122 citations
36. 36*

    Thermostatistics of a q-deformed Relativistic Ideal Fermi Gas

    Xu-Yang Hou🇨🇳 · H. Yan🇨🇳 · Hao Guo🇨🇳

    In this paper, we formulate a q-deformed many-body theory for the relativistic Fermi gas and discuss the effects of the deformation parameter q on physical properties of such systems. Since antiparticle excitations appear in the relativistic regime, a suitable treatment to the choice of deformation parameters for both fermions and antifermions must be carefully taken in order to get a consistent theory. By applying this formulation, we further study the thermostatistic properties of a q-deformed ideal relativistic Fermi gas. It can be shown that even in the noninteracting scenario, the system exhibits interesting characteristics which are significantly different from ordinary Fermi gases. Explicitly, antiparticles may become dominant due to the shift of chemical potential by the deformation parameter q. This may build a solid foundation for the further studies of q-deformed relativistic interacting systems.

    ↳ hep-thhep-phJ.Stat.Mech.(2020)·6 citations
37. 37*

    The effect of anisotropy on phase transitions in graphene

    M.E. Carrington🇨🇦 · A.R. Frey🇨🇦 · B.A. Meggison🇨🇦

    We study the effect of anisotropy (strain) on dynamical gap generation in graphene. We work with a low energy effective theory obtained from a tight-binding Hamiltonian expanded around the Dirac points in momentum space. We use a non-perturbative Schwinger-Dyson approach and calculate a coupled set of five momentum dependent dressing functions. Our results show that the critical coupling depends only weakly on the anisotropy parameter, and increases with greater anisotropy.

    ↳ cond-mat.mes-hallhep-phPRB(2020)·7 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.