Mon·Sep 30, 2019Monday·September 30, 2019

1. 01*

   Explaining Dijet Mass Excesses in ALEPH LEP2 Four-Jet Events with 2HDMs

   Abdesslam Arhrib🇲🇦 · Rachid Benbrik🇲🇦 · William Klemm🇸🇪 · Stefano Moretti🇬🇧 · Abdessamad Rouchad🇲🇦

   In this paper, we address the observability of four-jet signatures from light neutral and charged Higgs bosons at LEP2 energies in the framework of 2-Higgs Doublet Models (2HDMs). The main signal production channels are via $e^{+}{e}^{-}\to Ah$ and $H^{+}{H}^{-}$ with subsequent quark decays of such final states into four-jets. Specifically, Type-I and -III realizations of a generic 2HDM (2HDM-I and -III, respectively) are adopted to show that there exist points (under the assumption that the heavy Higgs state $H$ is SM-like) for which $(m_h,m_A,m_{H^{\pm }})\approx (80,30,55)$ GeV that can yield observable rates at LEP2 energies that can potentially explain the di-jet mass excesses seen recently in ALEPH data in a re-analysis of their four-jet samples, particularly so for the 2HDM-III.

   hep-ph1 citation
2. 02*

   An innovative approach for sketching the QCD phase diagram within the NJL model using Lagrange Multipliers

   Angelo Martínez🇲🇽 · Alfredo Raya🇲🇽

   We develop a new approach for sketching the quantum chromodynamics phase-diagram within the Nambu--Jona-Lasinio model for arbitrarily large values of the coupling constant, temperature and chemical potential based upon the strategy of Lagrange multipliers that constrains the corresponding gap equation and its mass gradient. Our approach distinguishes continuous from discountinuous phase transitions and thus is capable of locating the position of the Critical End Point from the thermodynamical parameters of the model alone, without direct reference to the chiral susceptibility or any other observable. The approach can be straightforwardly extended to those effective chiral quark models with a momentum independent constituent quark mass.

   hep-ph2 citations
3. 03*

   Study on possible molecular states composed of ${\Lambda }_c\bar{D}$ (${\Lambda }_{b}B$) and ${\Sigma }_c\bar{D}$ (${\Sigma }_{b}B$) within the Bethe-Salpeter framework

   Hong-Wei Ke🇨🇳 · Mei Li · Xiao-Hai Liu🇨🇳 · Xue-Qian Li🇨🇳

   $P_c(4312)$ observed by the LHCb collaboration is confirmed as a pentaquark and its structure, production, and decay behaviors attract great attention from theorists and experimentalists. Since its mass is very close to sum of ${\Sigma }_c$ and $\bar{D}$ masses, it is naturally tempted to be considered as a molecular state composed of ${\Sigma }_c$ and $\bar{D}$. Moreover, $P_c(4312)$ is observed in the channel with $J/\psi p$ final state, requiring that isospin conservation $P_c(4312)$ is an isospin-1/2 eigenstate. In literature, several groups used various models to estimate its spectrum. We systematically study the pentaquarks within the framework of the Bethe-Salpeter equation; thus $P_c(4312)$ is an excellent target because of the available data. We calculate the spectrum of $P_c(4312)$ in terms of the Bethe-Salpter equations and further study its decay modes. Some predictions on other possible pentaquark states that can be tested in future experiments are made.

   hep-phhep-exPRD(2020)·18 citations
4. 04*

   Correlations of conserved charges and QCD phase structure

   Rui Wen🇨🇳 · Wei-jie Fu🇨🇳

   Correlations of conserved charges, i.e., the baryon number, electric charge and the strangeness, have been calculated at finite temperature and chemical potential up to the fourth order. The calculations are done in a 2+1 flavor low energy effective theory, where quantum and thermal fluctuations are encoded through the evolution of flow equations within the functional renormalization group approach. Strangeness neutrality and a fixed ratio of the electric charge to the baryon number density are implemented throughout the computation. We find that higher-order correlations carry more sensitive critical dynamics in comparison to the quadratic ones, and a non-monotonic dependence of the fourth-order correlations between the baryon number and strangeness, $-{\chi }_{31}^{BS}/{\chi }_2^S$ and ${\chi }_{22}^{BS}/{\chi }_2^S$, on the collision energy is found.

   hep-phCPC(2021)·14 citations
5. 05*

   Evolution of magnetic fields in a transversely expanding highly conductive fluid

   M. Shokri🇮🇷 · N. Sadooghi🇮🇷

   Due to the absence of a transverse expansion with respect to the beam direction, the Bjorken flow is unable to describe certain observables in heavy ion collisions. This caveat has motivated the introduction of analytical relativistic hydrodynamics (RH) solutions with transverse expansion, in particular, the 3+1 self-similar (SSF) and Gubser flows. Inspired by recent generalizations of the Bjorken flow to the relativistic magnetohydrodynamics (RMHD), we present a procedure for a generalization of RH solutions to RMHD. Our method is mainly based on symmetry arguments. Using this method, we find the relation between RH degrees of freedom and the magnetic field evolution in the ideal limit for an infinitely conductive fluid, and determine the proper time dependence of the magnetic field in aforementioned flows. In the case of SSF, a family of solutions are found that are related through a certain differential equation. To find the magnetic field evolution in the Gubser flow, we solve RMHD equations for a stationary fluid in a conformally flat $d{S}^3\times E^1$ spacetime. The result is then Weyl transformed back into the Minkowski spacetime. In this case, the temporal evolution of the magnetic field exhibits a transmission between $1/t$ to $1/t^3$ near the center of the collision. The longitudinal component of the magnetic field is found to be sensitive to the transverse size of the fluid. We also find the radial evolution of the magnetic field for both flows. The radial domain of validity in the case of SSF is highly restricted, in contrast to the Gubser flow. A comparison of the results suggests that the Gubser RMHD may give a more appropriate qualitative picture of the magnetic field decay in the quark-gluon plasma (QGP).

   hep-phhep-thnucl-thPoS(2019)·1 citation
6. 06*

   On large mass $\gamma \gamma$ and $\gamma$-meson photoproduction

   L. Szymanowski🇵🇱 · B. Pire🇫🇷 · S. Wallon🇫🇷

   Enlarging the set of hard exclusive reactions to be studied in the framework of QCD collinear factorization opens new possibilities to access generalized parton distributions (GPDs). We studied the photoproduction of a large invariant mass photon-photon or photon-meson pair in the generalized Bjorken regime which may be accessible both at JLab and at the EIC.

   hep-phhep-exnucl-exnucl-th0 citations
7. 07*

   Non-standard interactions versus planet-scale neutrino oscillations

   Wei-Jie Feng🇨🇳 · Jian Tang🇨🇳 · Tse-Chun Wang🇨🇳 · Yi-Xing Zhou🇨🇳

   The low-energy threshold and the large detector size of Precision IceCube Next Generation Upgrade (PINGU) can make the study on neutrino oscillations with a planet-scale baseline possible. In this task, we consider the configuration that neutrinos are produced at CERN and detected in the PINGU detector, as a benchmark. We discuss its sensitivity of measuring the size of non-standard interactions (NSIs) in matter, which can be described by the parameter ${ϵ}_{\alpha \beta }$ ($\alpha$ and $\beta$ are flavors of neutrinos). We find that the CERN-PINGU configuration improves ${\widetilde{ϵ}}_{\mu \mu }\equiv {ϵ}_{\mu \mu }-{ϵ}_{\tau \tau }$ and ${ϵ}_{\mu \tau }$ significantly compared to the next-generation accelerator neutrino experiments. Most of degeneracy problems in the precision measurements can be resolved, except the one for ${\widetilde{ϵ}}_{\mu \mu }\sim -0.035$. Moreover, we point out that this configuration can also be used to detect the CP violation brought by NSIs. Finally, we compare the physics potential in this configuration to that for DUNE, T2HK and P2O, and find that the CERN-PINGU configuration can significantly improve the sensitivity to NSIs.

   hep-phPRD(2019)·10 citations
8. 08*

   Exploring the Tan contact term in Yang-Mills theory

   Ouraman Hajizadeh🇦🇹 · Markus Q. Huber🇩🇪 · Axel Maas🇦🇹 · Jan M. Pawlowski🇩🇪

   Reliably computing the free energy in a gauge theory like QCD is a challenging and resource-demanding endeavor. As an alternative, we explore here the possibility to obtain the associated thermodynamic anomaly by exploiting its relation to the Tan contact. Optimally, this would reduce the determination of the free energy to a high-precision calculation of two-point correlators. We study this possibility using the lattice and functional methods and compare them to the expected behavior for the SU(2) Yang-Mills case.

   hep-phhep-latPRD(2021)·5 citations
9. 09*

   Baryon modes in string breaking from gauge/string duality

   Oleg Andreev🇷🇺

   We consider the string breaking phenomenon within effective string models which purport to mimic QCD with two light flavors, with a special attention to baryon modes. We make some estimates of the string breaking distances at zero and non-zero baryon chemical potentials. Our estimates point towards the enhancement of baryon production in strong decays of heavy mesons in dense baryonic matter. We also suggest that the enhanced production of ${\Lambda }_c^{+}$ baryons in PbPb collisions is mainly due to larger values of chemical potential.

   hep-phhep-lathep-thnucl-thPLB(2020)·24 citations
10. 10*

    Top polarisation as a probe of CP-mixing top-Higgs coupling in $tjh$ signals

    Riley Patrick🇦🇺 · Andre Scaffidi🇦🇺 · Pankaj Sharma🇦🇺

    In this letter we explore beyond the Standard Model top-Higgs Yukawa couplings as a function of a CP-mixing parameter ${\xi }_t$ at the 14 TeV HL-LHC in the process $pp\to thj$. We observe that angular variables of the decay products of the top are non-trivially sensitive to ${\xi }_t$. This fact is exploited in a full detector level analysis that employs machine learning techniques to optimize signal sensitivity on a suite of variables, including lepton azimuthal angle. The key result of this study is an improved projected exclusion limit on ${\xi }_t$ even when including the realistic effects of detector smearing and a conservative estimate of systematic error.

    hep-phPRD(2020)·7 citations
11. 11*

    Dense two-color QCD from Dyson-Schwinger equations

    Romain Contant🇦🇹 · Markus Q. Huber🇩🇪

    We investigate quantum chromodynamics with two colors at nonvanishing density using Dyson-Schwinger equations. Lattice methods do not have a complex action problem in this theory. Thus, we can benchmark our results and the effect of truncations directly by comparing with the corresponding lattice results. We do so for the gluon propagator, the chiral condensate, and the quark number density and test variations of the employed truncation to improve the agreement. Finally, we compare the effect of a truncation on the chiral and confinement/deconfinement transitions in the phase diagrams of QCD and QCD with the gauge groups $SU(2)$ and $G_2$.

    hep-phhep-lathep-thPRD(2020)·31 citations
12. 12*

    Probing muonic forces with neutron star binaries

    Jeff A. Dror🇺🇸 · Ranjan Laha🇨🇭 · Toby Opferkuch🇨🇭

    We show that gravitational wave emission from neutron star binaries can be used to discover any generic long-ranged muonic force due to the large inevitable abundance of muons inside neutron stars. As a minimal consistent example, we focus on a gauged U(1)${}_{L_{\mu }-L_{\tau }}$ symmetry. In pulsar binaries, such U(1)${}_{L_{\mu }-L_{\tau }}$ vectors induce an anomalously fast decay of the orbital period through the emission of dipole radiation. We study a range of different pulsar binaries, finding the most powerful constraints for vector masses below $\mathcal{O}(10^{-18}\mathrm{eV})$. For merging binaries the presence of muons in neutron stars can result in dipole radiation as well as a modification of the chirp mass during the inspiral phase. We make projections for a prospective search using both the GW170817 and S190814bv events and find that current data can discover light vectors with masses below $\mathcal{O}(10^{-10}\mathrm{eV})$. In both cases, the limits attainable with neutron stars reach gauge coupling $g^{\prime }\lesssim 10^{-20}$, which are many orders of magnitude stronger than previous constraints. We also show projections for next generation experiments, such as Einstein Telescope and Cosmic Explorer.

    hep-phastro-ph.COastro-ph.HEPRD(2020)·60 citations
13. 13*

    Continuous Gravitational Waves and Magnetic Monopole Signatures from Single Neutron Stars

    P.V.S. Pavan Chandra🇮🇳 · Mrunal Korwar🇺🇸 · Arun M. Thalapillil🇮🇳

    Future observations of continuous gravitational waves from single neutron stars, apart from their monumental astrophysical significance, could also shed light on fundamental physics and exotic particle states. One such avenue is based on the fact that magnetic fields cause deformations of a neutron star, which results in a magnetic-field-induced quadrupole ellipticity. If the magnetic and rotation axes are different, this quadrupole ellipticity may generate continuous gravitational waves which may last decades, and may be observable in current or future detectors. Light, milli-magnetic monopoles, if they exist, could be pair-produced non-perturbatively in the extreme magnetic fields of neutron stars, such as magnetars. This non-perturbative production furnishes a new, direct dissipative mechanism for the neutron star magnetic fields. Through their consequent effect on the magnetic-field-induced quadrupole ellipticity, they may then potentially leave imprints in the early stage continuous gravitational wave emissions. We speculate on this possibility in the present study, by considering some of the relevant physics and taking a very simplified toy model of a magnetar as the prototypical system. Preliminary indications are that new-born millisecond magnetars could be promising candidates to look for such imprints. Deviations from conventional evolution, and comparatively abrupt features in the early stage gravitational waveforms, distinct from other astrophysical contributions, could be distinguishable signatures for these exotic monopole states.

    hep-phastro-ph.HEgr-qchep-thPRD(2020)·9 citations
14. 14*

    Physics Potential of ESS$\nu$SB in the presence of a Light Sterile Neutrino

    Sanjib Kumar Agarwalla🇮🇳 · Sabya Sachi Chatterjee🇬🇧 · Antonio Palazzo🇮🇹

    ESS$\nu$SB is a proposed neutrino super-beam project at the ESS facility. We study the performance of this setup in the presence of a light eV-scale sterile neutrino, considering 540 km baseline with 2 years (8 years) of $\nu$ ($\bar{\nu }$) run-plan. This baseline offers the possibility to work around the second oscillation maximum, providing high sensitivity towards CP-violation (CPV). We explore in detail its capability in resolving CPV generated by the standard CP phase ${\delta }_{13}$, the new CP phase ${\delta }_{14}$, and the octant of ${\theta }_{23}$. We find that the sensitivity to CPV induced by ${\delta }_{13}$ deteriorates noticeably when going from $3\nu$ to 4$\nu$ case. The two phases ${\delta }_{13}$ and ${\delta }_{14}$ can be reconstructed with a 1$\sigma$ uncertainty of $\sim 15^0$ and $\sim 35^0$ respectively. Concerning the octant of ${\theta }_{23}$, we find poor sensitivity in both $3\nu$ and $4\nu$ schemes. Our results show that a setup like ESS$\nu$SB working around the second oscillation maximum with a baseline of 540 km, performs quite well to explore CPV in 3$\nu$ scheme, but it is not optimal for studying CP properties in 3+1 scheme.

    hep-phhep-exJHEP(2019)·20 citations
15. 15*

    The proton structure via double parton scattering

    Matteo Rinaldi🇮🇹

    In this talk we present the results of the investigation on the so called double parton distribution functions (dPDFs), accessible quantities in high energy proton-proton and proton nucleus collisions, in double parton scattering processes (DPS). These new and almost unknown distributions encode information on how partons inside a proton are correlated among each other and represent a new tool to explore the three dimensional partonic structure of hadrons. In the present contribution, results of the calculations of dPFDs are presented also including phenomenological investigations on the impact of double correlations in experimental observables, showing how the latter could be observed in the next LHC run. In addition we discuss how present information on experimental observables could be related to the transverse proton structure.

    hep-phnucl-thJ.Phys.Conf.Ser.(2020)·1 citation
16. 16*

    Witten-Veneziano mechanism and pseudoscalar glueball-meson mixing in holographic QCD

    Josef Leutgeb🇦🇹 · Anton Rebhan🇦🇹

    We revisit the $U(1{)}_A$ anomaly in the holographic model of low-energy QCD by Witten, Sakai, and Sugimoto, presenting a new and direct derivation of the Witten-Veneziano mechanism for generating the mass of the ${\eta }^{\prime }$ through an anomalous mixing of the Ramond-Ramond $C_1$ field with the singlet component of the pseudoscalar mesons. The latter turns out to have a kinetic mixing with the normalizable modes of the $C_1$ field representing pseudoscalar glueballs, yielding additional vertices for their production and their decay that dominate over those of the unmixed case considered previously in the Witten-Sakai-Sugimoto model. The leading channel is predicted to be decay into two vector mesons, followed in importance by decay into three pseudoscalar mesons. The issue of production of pseudoscalar glueballs in radiative $J/\psi$ decays and in double diffractive processes is also discussed briefly.

    ↳ hep-thhep-phPRD(2020)·21 citations
17. 17*

    Radio constraints on dark matter annihilation in Canes Venatici I with LOFAR

    Martin Vollmann🇩🇪 · Volker Heesen🇩🇪 · Timothy Shimwell🇳🇱 · Martin J. Hardcastle🇬🇧 · Marcus Brüggen🇩🇪 · Günter Sigl🇩🇪 · Huub Röttgering🇳🇱

    Dwarf galaxies are dark matter-dominated and therefore promising targets for the search for weakly interacting massive particles (WIMPs), which are well-known candidates for dark matter. Annihilation of WIMPs produce ultra-relativistic cosmic-ray electrons and positrons that emit synchrotron radiation in the presence of magnetic fields. For typical magnetic field strengths (few $\mu$G) and $\mathcal{O}$(GeV--TeV) WIMP masses, this emission peaks at hundreds of MHz. Here, we use the non-detection of 150-MHz radio continuum emission from the dwarf spheroidal galaxy Canes Venatici I with the LOw-Frequency ARray (LOFAR) to derive constraints on the annihilation cross section of WIMPs into primary electron-positron and other fundamental particle-antiparticle pairs. Our main underlying assumption is that the transport of the cosmic rays can be described by the diffusion approximation, thus requiring a non-zero magnetic field strength with small-scale structure. In particular, by adopting magnetic field strengths of $\mathcal{O}(1\mu$G) and diffusion coefficients $\sim 10^{27}\mathrm{c}{\mathrm{m}}^2{\mathrm{s}}^{-1}$, we obtain limits that are comparable with those set by \emph{Fermi} Large Area Telescope using gamma-ray observations of this particular galaxy. Assuming s-wave annihilation and WIMPs making up 100 per cent of the DM density, our benchmark limits exclude several thermal WIMP realisations in the $[2,20]$-GeV mass range. We caution, however, that our limits for the cross section are subject to enormous uncertainties which we also quantitatively assess. In particular, variations on the propagation parameters or on the DM halo can shift our limits up by several orders of magnitude (in the pessimistic scenario).

    ↳ astro-ph.HEhep-phMNRAS(2020)·23 citations
18. 18*

    Gravitational Wave Anisotropies from Primordial Black Holes

    N. Bartolo🇮🇹 · D. Bertacca🇮🇹 · V. De Luca🇨🇭 · G. Franciolini🇨🇭 · S. Matarrese🇮🇹 · M. Peloso🇮🇹 · A. Ricciardone🇮🇹 · A. Riotto🇨🇭 · G. Tasinato🇬🇧

    An observable stochastic background of gravitational waves is generated whenever primordial black holes are created in the early universe thanks to a small-scale enhancement of the curvature perturbation. We calculate the anisotropies and non-Gaussianity of such stochastic gravitational waves background which receive two contributions, the first at formation time and the second due to propagation effects. The former contribution can be generated if the distribution of the curvature perturbation is characterized by a local and scale-invariant shape of non-Gaussianity. Under such an assumption, we conclude that a sizeable magnitude of anisotropy and non-Gaussianity in the gravitational waves would suggest that primordial black holes may not comply the totality of the dark matter.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2020)·107 citations
19. 19*

    Sp(4) gauge theories on the lattice: $N_f=2$ dynamical fundamental fermions

    Ed Bennett🇬🇧 · Deog Ki Hong🇰🇷 · Jong-Wan Lee🇰🇷 · C.-J. David Lin🇹🇼 · Biagio Lucini🇬🇧 · Maurizio Piai🇬🇧 · Davide Vadacchino🇮🇹

    We perform lattice studies of the gauge theory with Sp(4) gauge group and two flavours of (Dirac) fundamental matter. The global SU(4) symmetry is spontaneously broken by the fermion condensate. The dynamical Wilson fermions in the lattice action introduce a mass that breaks the global symmetry also explicitly. The resulting pseudo-Nambu-Goldstone bosons describe the SU(4)/Sp(4) coset, and are relevant, in the context of physics beyond the Standard Model, for composite Higgs models. We discuss scale setting, continuum extrapolation and finite volume effects in the lattice theory. We study mesonic composite states, which span representations of the unbroken Sp(4) global symmetry, and we measure masses and decay constants of the (flavoured) spin-0 and spin-1 states accessible to the numerical treatment, as a function of the fermion mass. With help from the effective field theory treatment of such mesons, we perform a first extrapolation towards the massless limit. We assess our results by critically comparing to the literature on other models and to the quenched results, and we conclude by outlining future avenues for further exploration. The results of our spectroscopic analysis provide new input data for future phenomenological studies in the contexts of composite Higgs models, and of dark matter models with a strongly coupled dynamical origin.

    ↳ hep-lathep-phJHEP(2019)·106 citations
20. 20*

    Total cross section and particle production in soft and hard processes at the LHC

    C. Royon🇺🇸

    We describe the most recent results at the Large Hadron Collider from the ALICE, ATLAS, CMS, LHCb and TOTEM experiments concerning the elastic, inelastic and total cross section measurements as well as particle production in soft and hard processes.

    ↳ hep-exhep-phPoS(2019)·1 citation
21. 21*

    Analytic integral solutions for induced gravitational waves

    Jinn-Ouk Gong🇰🇷

    We present analytic integral solutions for the second-order induced gravitational waves (GWs). After presenting all the possible second-order source terms, we calculate explicitly the solutions for the GWs induced by the linear scalar and tensor perturbations during matter- and radiation-dominated epochs.

    ↳ gr-qcastro-ph.COhep-phApJ(2022)·82 citations
22. 22*

    Pre-inflation and Trans-Planckian Censorship

    Yong Cai🇨🇳 · Yun-Song Piao🇨🇳

    We investigate the implication of Trans-Planckian Censorship Conjecture (TCC) for the initial state of primordial perturbations. It is possible to set the state of perturbation modes in the infinite past as the Minkowski vacuum, only if the pre-inflationary era is past-complete. We calculate the evolution of the perturbation modes in such a pre-inflationary era and show that at the beginning of inflation the perturbation modes with wavelengths much shorter than the Hubble scale (but still larger than the Planck length scale) will behave as they are in the Bunch-Davis state. Therefore, a past-complete pre-inflationary evolution may automatically prepare the initial state required for the inflationary perturbations at the CMB window while obeying the TCC.

    ↳ gr-qcastro-ph.COhep-phhep-thSCPMA(2020)·59 citations
23. 23*

    A DELPHES card for the CLIC detector

    Emilia Leogrande🇨🇭 · Philipp Roloff🇨🇭 · Ulrike Schnoor🇨🇭 · Matthias Weber🇨🇭

    The Compact Linear Collider, CLIC, is a multi-TeV electron-positron collider proposed for construction at CERN. A detector model, CLICdet, that is suited for the experimental conditions at CLIC and is based on realistic performance, has been developed. This paper describes the implementation of CLICdet in a fast simulation tool for particle physics collider experiments, DELPHES. The geometry of the detector concept as well as performance parameters extracted from full simulation studies are implemented in DELPHES parameter cards for CLICdet. Jet reconstruction for electron-positron colliders is added to the DELPHES analysis chain. Parameters for using DELPHES to simulate the detector effects of CLICdet are provided in three parameter cards, one for each energy stage of CLIC. The effects of beam-induced background at the higher-energy stages of CLIC are also incorporated. The results from the fast simulation with DELPHES are validated with respect to full detector simulation in a number of relevant processes.

    ↳ hep-exhep-ph48 citations
24. 24*

    Insights into the Origin of Mass

    Craig D. Roberts🇨🇳

    Atomic nuclei are the core of everything we can see. At the first level of approximation, their atomic weights are simply the sum of the masses of all the nucleons they contain. Each nucleon has a mass $m_N\approx 1$GeV, i.e. approximately 2000-times the electron mass. The Higgs boson produces the latter, but what produces the nucleon mass? This is the crux: the vast bulk of the mass of a nucleon is lodged with the energy needed to hold quarks together inside it; and that is supposed to be explained by quantum chromodynamics (QCD), the strong-interaction piece within the Standard Model. This contribution canvasses the potential for a coherent effort in QCD phenomenology and theory, coupled with experiments at existing and planned facilities, to reveal the origin and distribution of mass by focusing on the properties of the strong-interaction Nambu-Goldstone modes. Key experiments are approved at JLab 12; planned with COMPASS++/AMBER at CERN; and could deliver far-reaching insights by exploiting the unique capabilities foreseen at an electron ion collider.

    ↳ nucl-thhep-lathep-phnucl-exJ.Phys.Conf.Ser.(2020)·11 citations
25. 25*

    Constraining axion inflation with gravitational waves from preheating

    Peter Adshead🇺🇸 · John T. Giblin Jr🇺🇸 · Mauro Pieroni🇪🇸 · Zachary J. Weiner🇺🇸

    We study gravitational wave production from gauge preheating in a variety of inflationary models, detailing its dependence on both the energy scale and the shape of the potential. We show that preheating into Abelian gauge fields generically leads to a large gravitational wave background that contributes significantly to the effective number of relativistic degrees of freedom in the early universe, $N_{\mathrm{eff}}$. We demonstrate that the efficiency of gravitational wave production is correlated with the tensor-to-scalar ratio, $r$. In particular, we show that efficient gauge preheating in models whose tensor-to-scalar ratio would be detected by next-generation cosmic microwave background experiments ($r\gtrsim 10^{-3}$) will be either detected through its contribution to $N_{\mathrm{eff}}$ or ruled out. Furthermore, we show that bounds on $N_{\mathrm{eff}}$ provide the most sensitive probe of the possible axial coupling of the inflaton to gauge fields regardless of the potential.

    ↳ astro-ph.COhep-phPRD(2020)·142 citations
26. 26*

    Constraining axion inflation with gravitational waves across 29 decades in frequency

    Peter Adshead🇺🇸 · John T. Giblin Jr🇺🇸 · Mauro Pieroni🇪🇸 · Zachary J. Weiner🇺🇸

    We demonstrate that gravitational waves generated by efficient gauge preheating after axion inflation generically contribute significantly to the effective number of relativistic degrees of freedom $N_{\mathrm{eff}}$. We show that, with existing Planck limits, gravitational waves from preheating already place the strongest constraints on the inflaton's possible axial coupling to Abelian gauge fields. We demonstrate that gauge preheating can completely reheat the Universe regardless of the inflationary potential. Further, we quantify the variation of the efficiency of gravitational wave production from model to model and show that it is correlated with the tensor-to-scalar ratio. In particular, when combined with constraints on models whose tensor-to-scalar ratios would be detected by next-generation cosmic microwave background experiments, $r\gtrsim 10^{-3}$, constraints from $N_{\mathrm{eff}}$ will probe or rule out the entire coupling regime for which gauge preheating is efficient.

    ↳ astro-ph.COhep-phPRL(2020)·114 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.