HEP Phenomenology·hep-ph

Fri·Jun 18, 2021Friday·June 18, 2021

25 papers—13 primary·12 cross-listed·reconstructed*

01*
Super-Soft CP Violation
Alessandro Valenti🇮🇹 · Luca Vecchi🇮🇹
Solutions of the Strong CP Problem based on the spontaneous breaking of CP must feature a non-generic structure and simultaneously explain a coincidence between a priori unrelated CP-even and CP-odd mass scales. We show that these properties can emerge from gauge invariance and a CP-conserving, but otherwise generic, physics at the Planck scale. In our scenarios no fundamental scalar is introduced beyond the Standard Model Higgs doublet, and CP is broken at naturally small scales by a confining non-abelian dynamics. This approach is remarkably predictive: robustness against uncontrollable UV corrections to the QCD topological angle requires one or more families of vector-like quarks below a few $10$ 's of TeV, hence potentially accessible at colliders. Because CP violation is communicated to the SM at these super-soft scales, our solution of the Strong CP Problem is not spoiled by the presence of heavy new states motivated by other puzzles in physics beyond the Standard Model. In addition, these models generically predict a dark sector that may lead to interesting cosmological signatures.
hep-phJHEP(2021)·35 citations
02*
Dispersion relation analysis of the radiative corrections to $g_{A}$ in the neutron $β$ -decay
Mikhail Gorchtein🇩🇪 · Chien-Yeah Seng🇩🇪
We present the first and complete dispersion relation analysis of the inner radiative corrections to the axial coupling constant $g_{A}$ in the neutron $β$ -decay. Using experimental inputs from the elastic form factors and the spin-dependent structure function $g_{1}$ , we determine the contribution from the $γ W$ -box diagram to a precision better than $1 0^{- 4}$ . Our calculation indicates that the inner radiative corrections to the Fermi and the Gamow-Teller matrix element in the neutron $β$ -decay are almost identical, i.e. the ratio $λ = g_{A} / g_{V}$ is almost unrenormalized. With this result, we predict the bare axial coupling constant to be { $g ˚_{A} = - 1.2754 (13)_{exp} (2)_{RC}$ } based on the PDG average $λ = - 1.2756 (13)$
hep-phhep-latnucl-exnucl-thJHEP(2021)·45 citations
03*
Comagnetometer probes of dark matter and new physics
W. A. Terrano🇺🇸 · M. V. Romalis🇺🇸
We discuss the use of comagnetometry in studying new physics that couples to fermionic spin. Modern comagnetometry is -- in absolute energy units -- the most sensitive experimental technique for measuring the energy difference between quantum states, reaching sensitivities in the $1 0^{- 26}$ eV range. The technique suppresses the magnetic interactions of the spins, making searches for non-standard-model interactions possible. Many implementations have been developed and optimized for various uses. New physics scenarios which can be probed with comagnetometers include: EDMs, violations of Lorentz invariance, Goldstone bosons of new high-energy symmetries, CP-violating long-range forces, and axionic dark matter. We consider the prospects for improvements in the technique, and show -- based purely on signal-to-noise ratio with existing technology -- that there is room for several orders of magnitude in further improvement. We also evaluate several sources of systematic error and instability that may limit improvements.
hep-phphysics.atom-phQuantum Sci.Technol.(2022)·58 citations
04*
Recent highlights from GENIE v3
Luis Alvarez-Ruso🇪🇸 · Costas Andreopoulos🇬🇧 · Adi Ashkenazi🇺🇸 · Christopher Barry🇬🇧 · Steve Dennis🇬🇧 · Steve Dytman🇺🇸 · Hugh Gallagher🇺🇸 · Alfonso Andres Garcia Soto🇺🇸 · Steven Gardiner🇺🇸 · Walter Giele🇺🇸 · Robert Hatcher🇺🇸 · Or Hen🇺🇸 and 13 other authors
The release of GENIE v3.0.0 was a major milestone in the long history of the GENIE project, delivering several alternative comprehensive neutrino interaction models, improved charged-lepton scattering simulations, a range of beyond the Standard Model simulation capabilities, improved experimental interfaces, expanded core framework capabilities, and advanced new frameworks for the global analysis of neutrino scattering data and tuning of neutrino interaction models. Steady progress continued following the release of GENIE v3.0.0. New tools and a large number of new physics models, comprehensive model configurations, and tunes have been made publicly available and planned for release in v3.2.0. This article highlights some of the most recent technical and physics developments in the GENIE v3 series.
hep-phhep-exEur.Phys.J.ST(2021)·152 citations
05*
Inclusive Production of Heavy Quarkonia in pNRQCD
Nora Brambilla🇩🇪 · Hee Sok Chung🇩🇪 · Antonio Vairo🇩🇪
We develop a formalism for computing inclusive production cross sections of heavy quarkonia based on the nonrelativistic QCD and the potential nonrelativistic QCD effective field theories. Our formalism applies to strongly coupled quarkonia, which include excited charmonium and bottomonium states. Analogously to heavy quarkonium decay processes, we express nonrelativistic QCD long-distance matrix elements in terms of quarkonium wavefunctions at the origin and universal gluonic correlators. Our expressions for the long-distance matrix elements are valid up to corrections of order $1/ N_{c}^{2}$ . These expressions enhance the predictive power of the nonrelativistic effective field theory approach to inclusive production processes by reducing the number of nonperturbative unknowns, and make possible first-principle determinations of long-distance matrix elements once the gluonic correlators are known. Based on this formalism, we compute the production cross sections of $P$ -wave charmonia and bottomonia at the LHC, and find good agreement with measurements.
hep-phhep-exhep-latnucl-thJHEP(2021)·34 citations
06*
Deeply Virtual Compton Scattering in Improved Holographic QCD
Artur Amorim🇵🇹 · Miguel S. Costa🇵🇹 · Robert C. Quevedo🇵🇹
We present our current progress in the holographic computation of the scattering amplitude for Deeply Virtual Compton Scattering (DVCS) processe, as a function of the Mandelstam invariant $t$ . We show that it is possible to describe simultaneously the differential cross-section and total cross-section of DVCS data with a single holographic model for the pomeron. Using data from H1-ZEUS we obtained a $χ_{d o f}^{2} \sim 1.5$ for the best fit to the data.
hep-phhep-thPLB(2021)·1 citation
07*
Lepton mass effects in exclusive semileptonic $B_{c}$ -meson decays
Lopamudra Nayak🇮🇳 · Sonali Patnaik🇮🇳 · P. C. Dash🇮🇳 · Susmita Kar🇮🇳 · N. Barik🇮🇳
In this work, we discuss exclusive semileptonic $B_{c}$ -meson decays: $B_{c} \to η_{c} (J / ψ) l ν$ and $B_{c} \to D (D^{*}) l ν$ in the framework of the relativistic independent quark(RIQ) model based on an average flavor independent confining potential in equally mixed scalar-vector harmonic form. We calculate the invariant form factors representing decay amplitudes from the overlapping integrals of meson wave functions derivable in the RIQ model. To evaluate the lepton mass effects in the semileptonic decays, we first study the $q^{2}$ -dependence of the form factors in the accessible kinematic range of $q^{2}$ involved in the decay process in its $e^{-}$ and $τ^{-}$ mode separately. Similar studies on helicity amplitudes, $q^{2} -$ spectra for different helicity contributions, and total $q^{2}$ -spectra for each decay process are carried out separately in their $e^{-}$ and $τ^{-}$ modes. We predict the decay rates/ branching fractions, forward-backward asymmetry, and the asymmetry parameter in reasonable agreement with other model predictions, which can hopefully be tested in future experiments at the Tevatron and LHC. We also predict the observable $^{'} R^{'}$ which corresponds to the ratio of branching fractions for the decay process in its $e^{-}$ mode to its corresponding value in the $τ^{-}$ mode. Our results are comparable to another standard model(SM) predictions which highlight the failure of the lepton flavor universality hinting at new physics beyond SM for the explanation of the observed deviation of observable $^{'} R^{'}$ value from the corresponding SM predictions.
hep-phPRD(2021)·16 citations
08*
Optimising simulations for diphoton production at hadron colliders using amplitude neural networks
Joseph Aylett-Bullock🇬🇧 · Simon Badger🇮🇹 · Ryan Moodie🇬🇧
Machine learning technology has the potential to dramatically optimise event generation and simulations. We continue to investigate the use of neural networks to approximate matrix elements for high-multiplicity scattering processes. We focus on the case of loop-induced diphoton production through gluon fusion and develop a realistic simulation method that can be applied to hadron collider observables. Neural networks are trained using the one-loop amplitudes implemented in the NJet C++ library and interfaced to the Sherpa Monte Carlo event generator where we perform a detailed study for $2 \to 3$ and $2 \to 4$ scattering problems. We also consider how the trained networks perform when varying the kinematic cuts effecting the phase space and the reliability of the neural network simulations.
hep-phcs.AIcs.LGJHEP(2021)·54 citations
09*
A Model of Gravitational Leptogenesis
Graham M Shore🇬🇧
Gravitational leptogenesis is an elegant way of explaining the matter-antimatter asymmetry in the universe. This paper is a review of the recently proposed mechanism of radiatively-induced gravitational leptogenesis (RIGL), in which loop effects in QFT in curved spacetime automatically generate an asymmetry between leptons and antileptons in thermal quasi-equilibrium in the early universe. The mechanism is illustrated in a simple see-saw BSM model of neutrinos, where the lepton-number violating interactions required by the Sakharov conditions are mediated by right-handed neutrinos with Majorana masses of O(10^10) GeV. The Boltzmann equations are extended to include new, loop-induced gravitational effects and solved to describe the evolution of the lepton number asymmetry in the early universe. With natural choices of neutrino parameters, the RIGL mechanism is able to generate the observed baryon-to-photon ratio in the universe today.
hep-phgr-qcPeter Suranyi 87th Birthday Festschrift, …·2 citations
10*
Analytical Green's Functions for Continuum Spectra
Eugenio Megias🇪🇸 · Mariano Quiros🇪🇸
Green's functions with continuum spectra are a way of avoiding the strong bounds on new physics from the absence of new narrow resonances in experimental data. We model such a situation with a five-dimensional model with two branes along the extra dimension $z$ , the ultraviolet (UV) and the infrared (IR) one, such that the metric between the UV and the IR brane is AdS $_{5}$ , thus solving the hierarchy problem, and beyond the IR brane the metric is that of a linear dilaton model, which extends to $z \to \infty$ . This simplified metric, which can be considered as an approximation of a more complicated (and smooth) one, leads to analytical Green's functions (with a mass gap $m_{g} \sim TeV$ and a continuum for $s > m_{g}^{2}$ ) which could then be easily incorporated in the experimental codes. The theory contains Standard Model gauge bosons in the bulk with Neumann boundary conditions in the UV brane. To cope with electroweak observables the theory is also endowed with an extra custodial gauge symmetry in the bulk, with gauge bosons with Dirichlet boundary conditions in the UV brane, and without zero (massless) modes. All Green's functions have analytical expressions and exhibit poles in the second Riemann sheet of the complex plane at $s = M_{n}^{2} - i M_{n} Γ_{n}$ , denoting a discrete (infinite) set of broad resonances with masses ( $M_{n}$ ) and widths ( $Γ_{n}$ ). For gauge bosons with Neumann or Dirichlet boundary conditions, the masses and widths of resonances satisfy the (approximate) equation $s = - 4 m_{g}^{2} W_{n}^{2} [\pm (1 + i) /4]$ , where $W_{n}$ is the $n$ -th branch of the Lambert function.
hep-phhep-thJHEP(2021)·11 citations
11*
The Forward-Backward Asymmetry in $B \to D^{*} ℓ ν$ : One more hint for Scalar Leptoquarks?
Alexandre Carvunis🇫🇷 · Andreas Crivellin🇨🇭 · Diego Guadagnoli🇫🇷 · Shireen Gangal🇫🇷
Experimental data have provided intriguing hints for the violation of lepton flavour universality (LFU), including $B \to D^{(*)} τ ν / B \to D^{(*)} ℓ ν$ , the anomalous magnetic moment of the muon and $b \to s ℓ^{+} ℓ^{-}$ with a significance of $> 3 σ$ , $> 4 σ$ and $> 5 σ$ , respectively. Furthermore, in a recent re-analysis of 2018 Belle data, it was found that the forward-backward asymmetry ( $Δ A_{FB}$ ) of $B \to D^{*} μ ν ˉ$ vs $B \to D^{*} e ν ˉ$ disagrees with the SM prediction by $\approx 4 σ$ , providing an additional sign of LFU violation. We show that a tensor operator is necessary to significantly improve the agreement with data in $Δ A_{FB}$ while respecting the bounds from other $b \to c ℓ ν$ observables. Importantly, this tensor operator can only be induced (at tree-level within renormalizable models) by a scalar leptoquark. Furthermore, among the two possible representations, the $S U (2)_{L}$ -singlet $S_{1}$ and the doublet $S_{2}$ , which can interestingly both also account for the anomalous magnetic moment of the muon, only $S_{1}$ can provide a good fit. Even though the constraints from (differences of) other angular observables prefer a smaller value of $Δ A_{FB}$ than the current central one, this scenario is significantly preferred (nearly $4 σ$ ) over the SM hypothesis, and is compatible with constraints such as $B \to K^{*} ν ν$ and electroweak precision bounds. Therefore, if the $Δ A_{FB}$ anomaly is confirmed, it would provide circumstantial evidence for scalar leptoquarks and pave the way for a natural connection with all other anomalies pointing towards LFU violation.
hep-phhep-exhep-latPRD(2022)·36 citations
12*
Observing $t t ˉ Z$ spin correlations at the LHC
Baptiste Ravina🇬🇧 · Ethan Simpson🇬🇧 · James Howarth🇬🇧
Spin correlations in the production of top-antitop quark ( $t t ˉ$ ) pairs at the Large Hadron Collider (LHC) are an experimentally verified prediction of the Standard Model. In this paper, we compute the full spin density matrix for $t t ˉ Z$ production at next-to-leading order precision in QCD, for center-of-mass energies of 13 and 14 TeV. We find that the additional emission of a $Z$ boson leads to significantly different spin correlations with respect to the $t t ˉ$ case, and induces small longitudinal polarisations of the top quarks. We further propose an analysis strategy that could lead to the observation of spin correlations in $t t ˉ Z$ events at the end of Run 3 of the LHC, or possibly earlier by combining the ATLAS and CMS datasets. In addition, we show that the pure angular information contained in the spin density matrix provides novel constraints on the dimension-6 effective field theory (EFT) operators relevant to the $t$ - $Z$ interaction, without any reference to the total production rates.
hep-phhep-exEPJC(2021)·12 citations
13*
Indirect Detection of Secluded Supersymmetric Dark Matter
Patrick Barnes🇺🇸 · Zachary Johnson🇺🇸 · Aaron Pierce🇺🇸 · Bibhushan Shakya🇩🇪
Weak-scale secluded sector dark matter can reproduce the observed dark matter relic density with thermal freeze-out within that sector. If nature is supersymmetric, three portals to the visible sector - a gauge portal, a Higgs portal, and a gaugino portal - are present. We present gamma ray spectra relevant for indirect detection of dark matter annihilation in such setups. Since symmetries in the secluded sector can stabilize dark matter, $R$ -parity is unnecessary, and we investigate the impact of $R$ -parity violation on annihilation spectra. We present limits from the Fermi Large Area Telescope observations of dwarf galaxies and projections for Cherenkov Telescope Array observations of the galactic center. Many of our results are also applicable to generic, non-supersymmetric setups.
hep-phastro-ph.COPRD(2022)·7 citations
14*
Diquark properties from full QCD lattice simulations
Anthony Francis🇨🇭 · Philippe de Forcrand🇨🇭 · Randy Lewis🇨🇦 · Kim Maltman🇨🇦
We study diquarks on the lattice in the background of a static quark, in a gauge-invariant formalism with quark masses down to almost physical $m_{π}$ . We determine mass differences between diquark channels as well as diquark-quark mass differences. The lightest and next-to-lightest diquarks have "good" scalar, $3 ˉ_{F}$ , $3 ˉ_{c}$ , $J^{P} = 0^{+}$ , and "bad" axial vector, $6_{F}$ , $3 ˉ_{c}$ , $J^{P} = 1^{+}$ , quantum numbers, and a bad-good mass difference for $u d$ flavors, $198 (4) MeV$ , in excellent agreement with phenomenological determinations. Quark-quark attraction is found only in the "good" diquark channel. We extract a corresponding diquark size of $\sim 0.6 fm$ and perform a first exploration of the "good" diquark shape, which is shown to be spherical. Our results provide quantitative support for modeling the low-lying baryon spectrum using good light diquark effective degrees of freedom.
↳ hep-lathep-phnucl-thJHEP(2022)·42 citations
15*
Hidden Sectors from Multiple Line Bundles for the $B - L$ MSSM
Anthony Ashmore🇺🇸 · Sebastian Dumitru🇺🇸 · Burt A. Ovrut🇺🇸
We give a formalism for constructing hidden sector bundles as extensions of sums of line bundles in heterotic $M$ -theory. Although this construction is generic, we present it within the context of the specific Schoen threefold that leads to the physically realistic $B - L$ MSSM model. We discuss the embedding of the line bundles, the existence of the extension bundle, and a number of necessary conditions for the resulting bundle to be slope-stable and thus $N = 1$ supersymmetric. An explicit example is presented, where two line bundles are embedded into the $S U (3)$ factor of the $E_{6} \times S U (3)$ maximal subgroup of the hidden sector $E_{8}$ gauge group, and then enhanced to a non-Abelian $S U (3)$ bundle by extension. For this example, there are in fact six inequivalent extension branches, significantly generalizing that space of solutions compared with hidden sectors constructed from a single line bundle.
↳ hep-thhep-phFortsch.Phys.(2022)·5 citations
16*
Continuous evolution of electromagnetic field in heavy-ion collisions
Evan Stewart🇺🇸 · Kirill Tuchin🇺🇸
In heavy-ion collisions the electromagnetic field exists before the hot nuclear matter emergence. Requiring the field continuity we compute it in the central rapidity region by taking into account the electromagnetic response of the Quark Gluon Plasma. We show that the electromagnetic field is nearly time-independent from about 1~fm/c after the collision until the freezeout.
↳ nucl-thhep-phNPA(2021)·26 citations
17*
Search for the $η_{c 2} (1 D)$ in $e^{+} e^{-} \to γ η_{c 2} (1 D)$ at $s$ near 10.6 GeV at Belle
Belle Collaboration: S. Jia · C. P. Shen · I. Adachi · H. Aihara · S. Al Said · D. M. Asner · T. Aushev · R. Ayad · V. Babu · P. Behera · K. Belous · J. Bennett and 188 other authors
For the first time we search for the $η_{c 2} (1 D)$ in $e^{+} e^{-} \to γ η_{c 2} (1 D)$ at $s$ = 10.52, 10.58, and 10.867 GeV with data samples of 89.5 fb $^{- 1}$ , 711 fb $^{- 1}$ , and 121.4 fb $^{- 1}$ , respectively, accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant $η_{c 2} (1 D)$ signal is observed in the mass range between 3.8 and 3.88 GeV/ $c^{2}$ . The upper limit at 90\% confidence level on the product of the Born cross section for $e^{+} e^{-} \to γ η_{c 2} (1 D)$ and branching fraction for $η_{c 2} (1 D) \to γ h_{c} (1 P)$ is determined to be $σ (e^{+} e^{-} \to γ η_{c 2} (1 D)) B (η_{c 2} (1 D) \to γ h_{c} (1 P))$ $<$ 4.9 fb at $s$ near 10.6 GeV.
↳ hep-exhep-phPRD(2021)·4 citations
18*
Tilted Dirac cone effects and chiral symmetry breaking in a planar four-fermion model
Y. M. P. Gomes🇧🇷 · Rudnei O. Ramos🇧🇷
We analyze the chiral symmetry breaking in a planar four-fermion model with non-null chemical potential, temperature and including the effect of the tilt of the Dirac cone. The system is modeled with a $(2 + 1)$ -dimensional Gross-Neveu-like interaction model in the context of the generalized Weyl Hamiltonian and its phase structure is studied in the mean-field and large- $N$ approximations. Possible applications of the results obtained, e.g., in connection to graphene, are discussed. We also discuss the effect of an external magnetic field applied to the system, which can give rise to the appearance of the anomalous Hall effect and that is expected to arise in connection with two-dimensional Weyl and Dirac semimetals.
↳ cond-mat.mes-hallhep-phhep-thPRB(2021)·15 citations
19*
Search for the chiral magnetic effect via charge-dependent azimuthal correlations relative to spectator and participant planes in Au+Au collisions at $s_{N N}$ = 200 GeV
STAR Collaboration: M. S. Abdallah · J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · I. Aggarwal · M. M. Aggarwal · Z. Ahammed · I. Alekseev · D. M. Anderson · A. Aparin and 377 other authors
The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field due to imbalanced chirality of quarks in local parity and charge-parity violating domains in quantum chromodynamics. The experimental measurement of the charge separation is made difficult by the presence of a major background from elliptic azimuthal anisotropy. This background and the CME signal have different sensitivities to the spectator and participant planes, and could thus be determined by measurements with respect to these planes. We report such measurements in Au+Au collisions at a nucleon-nucleon center-of-mass energy of 200 GeV at the Relativistic Heavy-Ion Collider. It is found that the charge separation, with the flow background removed, is consistent with zero in peripheral (large impact parameter) collisions. Some indication of finite CME signals is seen in mid-central (intermediate impact parameter) collisions. Significant residual background effects may, however, still be present.
↳ nucl-exhep-exhep-phnucl-thPRL(2022)·61 citations
20*
Precision Higgs Measurements at the 250 GeV ILC
Tomohisa Ogawa🇯🇵
The plan for the International Linear Collider (ILC) is now being prepared as a staged design, with the first stage of 2 $a b^{- 1}$ at 250GeV and later stages achieving the full project specifications with 4 $a b^{- 1}$ at 500 GeV. The talk presents the capabilities for precision Higgs boson measurements at 250 GeV. It is shown that the 250 GeV stage of the ILC will already provide many compelling results in Higgs physics, with new measurements unavailable at the Large Hadron Collider, model-independent determinations of key parameters, and possible discrimination of a variety of scenarios for new physics.
↳ hep-exhep-phPoS(2019)·1 citation
21*
Investigations of the linear and non-linear flow harmonics using the A Multi-Phase Transport model
Niseem Magdy🇺🇸
The Multi-Phase Transport model (AMPT) is used to study the effects of the parton-scattering cross-sections ( $σ_{pp}$ ) and hadronic re-scattering on the linear contributions to the flow harmonic $v_{4}$ , the non-linear response coefficients, and the correlations between different order flow symmetry planes in Au+Au collisions at 200~GeV. The model results, which agree with current experimental measurements, indicate that the higher-order flow harmonics are sensitive to the $σ_{pp}$ variations. However, the non-linear response coefficients and the correlations between different order flow symmetry planes are $σ_{pp}$ independent. These results suggest that further detailed experimental measurements which span a broad range of collision systems and beam energies could serve as an additional constraint for the theoretical models' calculations.
↳ nucl-thhep-phnucl-exJ.Phys.G(2022)·10 citations
22*
Some Aspects of the Tachyon Inflation with Superpotential in Confrontation with Planck2018 Data
Narges Rashidi🇮🇷
We study the tachyon inflation in the presence of the superpotential as an inflationary potential. We study the primordial perturbations and their non-gaussian feature in the equilateral configuration. We use the Planck2018 TT, TE, EE+lowE+lensing+BK14+BAO joint data at $68%$ CL and $95%$ CL, to perform numerical analysis on the scalar perturbations and seek for the observational viability of the tachyon inflation with superpotential. We also check the observational viability of the model by studying the tensor part of the perturbations and comparing the results with Planck2018 TT, TE, EE+lowE+lensing+BK14+BAO+ LIGO $&$ Virgo2016 joint data at $68%$ CL and $95%$ CL. By studying the phase space of the model's parameters, we predict the amplitude of the equilateral non-gaussianity in this model. The reheating phase after inflation is another issue that is explored in this paper. We show that, in some ranges of the model's parameters, it is possible to have an observationally viable tachyon model with superpotential.
↳ astro-ph.COhep-phhep-thApJ(2021)·6 citations
23*
Escape from supercooling with or without bubbles: gravitational wave signatures
Marek Lewicki🇵🇱 · Oriol Pujolàs🇪🇸 · Ville Vaskonen🇪🇸
Quasi-conformal models are an appealing scenario that can offer naturally a strongly supercooled phase transition and a period of thermal inflation in the early Universe. A crucial aspect for the viability of these models is how the Universe escapes from the supercooled state. One possibility is that thermal inflation phase ends by nucleation and percolation of true vacuum bubbles. This route is not, however, always efficient. In such case another escape mechanism, based on the growth of quantum fluctuations of the scalar field that eventually destabilize the false vacuum, becomes relevant. We study both of these cases in detail in a simple yet representative model. We determine the duration of the thermal inflation, the curvature power spectrum generated for the scales that exit horizon during the thermal inflation, and the stochastic gravitational wave background from the phase transition. We show that these gravitational waves provide an observable signal from the thermal inflation in almost the entire parameter space of interest. Furthermore, the shape of the gravitational wave spectrum can be used to ascertain how the Universe escaped from supercooling.
↳ astro-ph.COhep-phhep-thEPJC(2021)·55 citations
24*
Stochastic Inflation at NNLO
Timothy Cohen🇺🇸 · Daniel Green🇺🇸 · Akhil Premkumar🇺🇸 · Alexander Ridgway🇺🇸
Stochastic Inflation is an important framework for understanding the physics of de Sitter space and the phenomenology of inflation. In the leading approximation, this approach results in a Fokker-Planck equation that calculates the probability distribution for a light scalar field as a function of time. Despite its successes, the quantum field theoretic origins and the range of validity for this equation have remained elusive, and establishing a formalism to systematically incorporate higher order effects has been an area of active study. In this paper, we calculate the next-to-next-to-leading order (NNLO) corrections to Stochastic Inflation using Soft de Sitter Effective Theory (SdSET). In this effective description, Stochastic Inflation manifests as the renormalization group evolution of composite operators. The leading impact of non-Gaussian quantum fluctuations appears at NNLO, which is presented here for the first time; we derive the coefficient of this term from a two-loop anomalous dimension calculation within SdSET. We solve the resulting equation to determine the NNLO equilibrium distribution and the low-lying relaxation eigenvalues. In the process, we must match the UV theory onto SdSET at one-loop order, which provides a non-trivial confirmation that the separation into Wilson-coefficient corrections and contributions to initial conditions persists beyond tree level. Furthermore, these results illustrate how the naive factorization of time and momentum integrals in SdSET no longer holds in the presence of logarithmic divergences. It is these effects that ultimately give rise to the renormalization group flow that yields Stochastic Inflation.
↳ hep-thastro-ph.COgr-qchep-phJHEP(2021)·82 citations
25*
The Gravitational-Wave Physics II: Progress
Ligong Bian🇨🇳 · Rong-Gen Cai🇨🇳 · Shuo Cao🇨🇳 · Zhoujian Cao🇨🇳 · He Gao🇨🇳 · Zong-Kuan Guo🇨🇳 · Kejia Lee🇨🇳 · Di Li🇨🇳 · Jing Liu🇨🇳 · Youjun Lu🇨🇳 · Shi Pi🇨🇳 · Jian-Min Wang🇨🇳 and 6 other authors
It has been a half-decade since the first direct detection of gravitational waves, which signifies the coming of the era of the gravitational-wave astronomy and gravitational-wave cosmology. The increasing number of the detected gravitational-wave events has revealed the promising capability of constraining various aspects of cosmology, astronomy, and gravity. Due to the limited space in this review article, we will briefly summarize the recent progress over the past five years, but with a special focus on some of our own work for the Key Project ``Physics associated with the gravitational waves'' supported by the National Natural Science Foundation of China. In particular, (1) we have presented the mechanism of the gravitational-wave production during some physical processes of the early Universe, such as inflation, preheating and phase transition, and the cosmological implications of gravitational-wave measurements; (2) we have put constraints on the neutron star maximum mass according to GW170817 observations; (3) we have developed a numerical relativity algorithm based on the finite element method and a waveform model for the binary black hole coalescence along an eccentric orbit.
↳ gr-qcastro-ph.COastro-ph.HEhep-phSCPMA(2021)·109 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.