Thu·May 28, 2020Thursday·May 28, 2020

1. 01*

   Nucleon and dinucleon decays to leptonic final states in a left-right symmetric model with large extra dimensions

   Sudhakantha Girmohanta🇺🇸

   We consider baryon-number-violating nucleon and dinucleon decays to leptonic final states in the context of a left-right symmetric (LRS) model with large extra dimensions. Specifically, we study (a) nucleon to trilepton decays with $\Delta B=-1$ and $\Delta L=-3$, and (b) dinucleon to dilepton decays with $\Delta B=-2$ and $\Delta L=-2$. In the LRS model, $B-L$ is gauged and is spontaneously broken by a Higgs vacuum expectation value $v_R$, which characterizes the scale at which processes violating $B-L$ occur. We show that together with the lower bound on $v_R$ from experimental limits on $n$-$\bar{n}$ oscillations, constraints from searches for other nucleon decay modes imply sufficient suppression of these nucleon to trilepton and dinucleon to dilepton decay modes in this model to agree with experimental bounds.

   hep-phEPJC(2021)·10 citations
2. 02*

   $J/\psi$ meson production in association with an open charm hadron at the LHC: A reappraisal

   Hua-Sheng Shao🇫🇷

   We critically (re)examine the associated production process of a $J/\psi$ meson plus an open charm hadron at the LHC in the proton-proton ($pp$) and proton-lead ($p\mathrm{Pb}$) collisions. Such a process is very intriguing in the sense of tailoring to explore the double parton structure of nucleons and to determine the geometry of partons in nuclei. In order to interpret the existing $pp$ data with the LHCb detector at the center-of-mass energy $\sqrt{s}=7$ TeV, we introduce two overlooked mechanisms for the double parton scattering (DPS) and single parton scattering (SPS) processes. Besides the conventional DPS mode, where the two mesons are produced almost independently in the two separate scattering subprocesses, we propose a novel DPS mechanism that the two constituent (heavy) quarks stemming from two hard scatterings can form into a composite particle, like the $J/\psi$ meson, during the hadronization phase. However, it turns out the corresponding contribution is small in $J/\psi +c\bar{c}$ hadroproduction. On the contrary, we point out that the resummation of the initial state logarithms due to gluon splitting into a charm quark pair is crucial to understand the LHCb measurement, which was overlooked in the literature. We perform a proper matching between the perturbative calculations in different initial-quark flavor number schemes, generically referring to the variable flavor number scheme. The new variable flavor number scheme calculation for the process strongly enhance the SPS cross sections, almost closing the discrepancies between theory and experiment. Finally, we present our predictions for the forthcoming LHCb measurement in $p\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=8.16$ TeV. Some interesting observables are exploited to set up the control regions of the DPS signal and to probe the impact-parameter dependent parton densities in lead.

   hep-phhep-exnucl-exnucl-thPRD(2020)·18 citations
3. 03*

   Study of Jet Quenching in Relativistic Heavy-Ion Collisions

   Fabio Canedo🇧🇷

   In this work, we investigate possible impacts that the behavior of the Quark-Gluon Plasma might have on Jet Observables. We choose JEWEL (Jet Evolution With Energy Loss) for this study. We have coupled JEWEL with ${\mathrm{T}}_{\mathrm{R}}\mathrm{ENTo}$ and also with MC-KLN+vUSPhydro for simulations. The simulations were performed for PbPb collisions at $\sqrt{s_{NN}}=2.76\mathrm{TeV}$ in the $0-10\%$ centrality class. We have found that jet shape observables are mainly unchanged by the inclusion of realistic hydrodynamics and initial conditions in these settings. We also made calculations for the jet $v_2$. In this case, we have found that initial conditions do not affect this observable. In the case of realistic hydrodynamics, there is an improvement in the description of data.

   hep-ph5 citations
4. 04*

   Rapidity Logarithms in SCET Without Modes

   Matthew Inglis-Whalen🇨🇦 · Michael Luke🇨🇦 · Aris Spourdalakis🇨🇦

   We re-examine observables with rapidity divergences in the context of a formulation of Soft-Collinear Effective Theory in which infrared degrees of freedom are not explicitly separated into modes. We consider the Sudakov form factor with a massive vector boson and Drell-Yan production of lepton pairs at small transverse momentum as demonstrative examples. In this formalism, rapidity divergences introduce a scheme dependence into the effective theory and are associated with large logarithms appearing in the soft matching conditions. This scheme dependence may be used to derive the corresponding rapidity renormalization group equations, and rates naturally factorize into hard, soft and jet contributions without the introduction of explicit modes.

   hep-phNPA(2021)·7 citations
5. 05*

   The Constituent Counting Rule and Omega Photoproduction

   Trevor Reed🇺🇸 · Christopher Leon🇺🇸 · Frank Vera🇺🇸 · Lei Guo🇺🇸 · Brian Raue🇺🇸

   The constituent counting ruling (CCR) has been found to hold for numerous hard, exclusive processes. It predicts the differential cross section at high energies and fixed $\cos {\theta }_{c.m.}$ should follow $\frac{d\sigma }{dt}\sim \frac{1}{s^{n-2}}$, where $n$ is the minimal number of constituents involved in the reaction. Here we provide an in-depth analysis of the reaction $\gamma p\to \omega p$ at ${\theta }_{c.m.}\sim 90^{\circ }$ using CLAS data with an energy range of $s=5-8$ GeV${}^2$, where the CCR has been shown to work in other reactions. We argue for a stringent method to select data to test the CCR and utilize a Taylor-series expansion to take advantage of data from nearby angle bins in our analysis. Naïvely, this reaction would have $n=9$ (or $n=10$ if the photon is in a $q\bar{q}$ state) and we would expect a scaling of $\sim s^{-7}$ ($s^{-8}$). Instead, a scaling of $s^{-(9.08\pm 0.11)}$ was observed. Explanations for this apparent failure of the naïve CCR assumptions are examined.

   hep-phnucl-exnucl-thPRC(2021)·3 citations
6. 06*

   Supernovae neutrino detection via coherent scattering off silicon nuclei

   Ana Luisa Foguel🇧🇷 · Eduardo Souza Fraga🇧🇷 · Carla Bonifazi🇧🇷

   Low-energy neutrinos are clean messengers from supernovae explosions and probably carry unique insights into the process of stellar evolution. We estimate the expected number of events considering coherent elastic scattering of neutrinos off silicon nuclei, as would happen in Charge Coupled Devices (CCD) detectors. The number of expected events, integrated over a window of about 18 s, is $\sim$ 4 if we assume 10 kg of silicon and a supernovae 1 kpc away. For a distance similar to the red supergiant Betelgeuse, the number of expected events increases to $\sim$ 30 - 120, depending on the supernovae model. We argue that silicon detectors can be effective for supernovae neutrinos, and might possibly distinguish between models for certain target masses and distances.

   hep-phastro-ph.HEAstropart.Phys.(2021)·6 citations
7. 07*

   Modified MIT bag Models -- part I: Thermodynamic consistency, stability windows and symmetry group

   Luiz L. Lopes🇧🇷 · Carline Biesdorf🇧🇷 · Débora P. Menezes🇧🇷

   In this work we study different variations of the MIT bag model. We start with the so called non-ideal bag model and discuss it in detail. Then we implement a vector interaction in the MIT bag model that simulates a meson exchange interaction and fix the quark-meson coupling constants via symmetry group theory. At the end we propose an original model, inspired by the Boguta-Bodmer models, which allows us to control the repulsion interaction at high densities. For each version of the model we obtain a stability window as predicted by the Bodmer-Witten conjecture and discuss its thermodynamic consistency.

   hep-phastro-ph.HEnucl-thPhys.Scripta(2021)·73 citations
8. 08*

   Modified majoron model for cosmological anomalies

   Gabriela Barenboim🇪🇸 · Ulrich Nierste🇩🇪

   The vacuum expectation value $v_s$ of a Higgs triplet field $\Delta$ carrying two units of lepton number $L$ induces neutrino masses $\propto v_s$. The neutral component of $\Delta$ gives rise to two Higgs particles, a pseudoscalar $A$ and a scalar $S$. The most general renormalizable Higgs potential $V$ for $\Delta$ and the Standard-Model Higgs doublet $\Phi$ does not permit the possibility that the mass of either $A$ or $S$ is small, of order $v_s$, while the other mass is heavy enough to forbid the decay $Z\to AS$ to comply with LEP 1 data. We present a model with additional dimension-6 terms in $V$, in which this feature is absent and either $A$ or $S$ can be chosen light. Subsequently we propose the model as a remedy to cosmological anomalies, namely the tension between observed and predicted tensor-to-scalar mode ratios in the cosmic microwave background and the different values of the Hubble constant measured at different cosmological scales. Furthermore, if $\Delta$ dominantly couples to the third-generation doublet $L_{\tau }=({\nu }_{\tau },\tau )$, the deficit of ${\nu }_{\tau }$ events at IceCube can be explained. The singly and doubly charged triplet Higgs bosons are lighter than 280 GeV and 400 GeV respectively, and could be found at the LHC.

   hep-phastro-ph.COastro-ph.HEPRD(2021)·12 citations
9. 09*

   Precise predictions for double-Higgs production via vector-boson fusion

   Frédéric A. Dreyer🇬🇧 · Alexander Karlberg🇬🇧 · Jean-Nicolas Lang🇨🇭 · Mathieu Pellen🇬🇧

   Theoretical predictions with next-to-next-to-leading order (NNLO) QCD accuracy combined with the next-to-leading order (NLO) electroweak (EW) corrections are presented for differential observables of the double-Higgs production process via vector-boson fusion. While the QCD corrections were previously known, the EW ones are computed here for the first time. The numerical results are obtained for a realistic experimental set-up at the LHC and are presented in the form of fiducial cross sections and differential distributions. Within this setup we find that the VBF approximation employed in the NNLO QCD correction is accurate at the sub-percent level. We find that the NLO EW corrections within the fiducial volume are $-6.1\%$, making them of almost the same order as the NLO QCD corrections. In some kinematic regions they can grow as large as $-30\%$ making them the dominant radiative corrections. When the EW corrections are combined with the NNLO QCD corrections we find a total correction of $-14.8\%$. The results presented here thus comprise the state-of-the-art theoretical predicition for the double-Higgs production via vector-boson fusion, which will be of value to the high-luminosity programme at the LHC.

   hep-phhep-exEPJC(2020)·44 citations
10. 10*

    Dark Matter-Neutrino Interconversion at COHERENT, Direct Detection, and the Early Universe

    Nicholas Hurtado🇺🇸 · Hana Mir🇺🇸 · Ian M. Shoemaker🇺🇸 · Eli Welch🇺🇸 · Jason Wyenberg🇺🇸

    We study a Dark Matter (DM) model in which the dominant coupling to the standard model occurs through a neutrino-DM-scalar coupling. The new singlet scalar will generically have couplings to nuclei/electrons arising from renormalizable Higgs portal interactions. As a result the DM particle $X$ can convert into a neutrino via scattering on a target nucleus $\mathcal{N}$: $X+\mathcal{N}\to \nu +\mathcal{N}$, leading to striking signatures at direct detection experiments. Similarly, DM can be produced in neutrino scattering events at neutrino experiments: $\nu +\mathcal{N}\to X+\mathcal{N}$, predicting spectral distortions at experiments such as COHERENT. Furthermore, the model allows for late kinetic decoupling of dark matter with implications for small-scale structure. At low masses, we find that COHERENT and late kinetic decoupling produce the strongest constraints on the model, while at high masses the leading constraints come from DM down-scattering at XENON1T and Borexino. Future improvement will come from CE$\nu$NS data, ultra-low threshold direct detection, and rare kaon decays.

    hep-phastro-ph.COhep-exPRD(2020)·19 citations
11. 11*

    Light dark matter in a minimal extension with two additional real singlets

    Markos Maniatis🇨🇱

    The direct searches for heavy scalar dark matter with a mass of order 100 GeV are much more sensitive than for light dark matter of order 1 GeV. The question arises whether dark matter could be light and has escaped detection so far. We study a simple extension of the Standard Model with two additional real singlets. We show that this simple extension may provide the observed relic dark matter density, does neither disturb big-bang nucleosynthesis nor the cosmic microwave background radiation observations and fulfills the conditions of clumping behavior for different sizes of galaxies. The potential of one Standard Model-like Higgs-boson doublet and the two singlets gives rise to a changed Higgs phenomenology, in particular, an enhanced invisible Higgs-boson decay rate is expected, detectable by missing transversal momentum searches at the ATLAS and CMS experiments at CERN.

    hep-phPRD(2021)·4 citations
12. 12*

    Extending Trinity to the Scalar Sector through Discrete Flavoured Symmetries

    João M. Alves🇵🇹 · Francisco J. Botella🇪🇸 · Gustavo C. Branco🇵🇹 · Miguel Nebot🇵🇹

    We conjecture the existence of a relation between elementary scalars and fermions, making it plausible the existence of three Higgs doublets. We introduce a Trinity Principle (TP) which, given the fact that there are no massless quarks, requires the existence of a minimum of three Higgs doublets. The TP states that each line of the mass matrix of a quark of a given charge should receive the contribution from one and only one scalar doublet and furthermore a given scalar doublet should contribute to one and only one line of the mass matrix of a quark of a given charge. This principle is analogous to the Natural Flavour Conservation (NFC) of Glashow and Weinberg with the key distinction that NFC required the introduction of a flavour blind symmetry, while the TP requires a flavoured symmetry, to be implemented in a natural way. We provide two examples which satisfy the Trinity Principle based on ${\mathbb{Z}}_3$ and ${\mathbb{Z}}_2\times {\mathbb{Z}}_2^{\prime }$ flavoured symmetries, and show that they are the minimal multi-Higgs extensions of the Standard Model where CP can be imposed as a symmetry of the full Lagrangian and broken by the vacuum, without requiring soft-breaking terms. We show that the vacuum phases are sufficient to generate a complex CKM matrix, in agreement with experiment. The above mentioned flavoured symmetries lead to a strong reduction in the number of parameters in the Yukawa interactions, enabling a control of the Scalar Flavour Changing Neutral Couplings (SFCNC). We analyse some of the other physical implications of the two models, including an estimate of the enhancement of the Baryon Asymmetry of the Universe provided by the new sources of CP violation, and a discussion of the the strength of their tree-level SFCNC.

    hep-phEPJC(2020)·9 citations
13. 13*

    Natural axion model from flavour

    Salvador Centelles Chuliá🇪🇸 · Christian Döring🇩🇪 · Werner Rodejohann🇩🇪 · Ulises J. Saldaña-Salazar🇩🇪

    We explore a common symmetrical origin for two long standing problems in particle physics: the strong CP and the fermion mass hierarchy problems. The Peccei--Quinn mechanism solves the former one with an anomalous global $U(1{)}_{\mathrm{PQ}}$ symmetry. Here we investigate how this $U(1{)}_{\mathrm{PQ}}$ could at the same time explain the fermion mass hierarchy. We work in the context of a four-Higgs-doublet model which explains all quark and charged fermion masses with natural, i.e.\ order $1$, Yukawa couplings. Moreover, the axion of the model constitutes a viable dark matter candidate and neutrino masses are incorporated via the standard type-I seesaw mechanism. A simple extension of the model allows for Dirac neutrinos.

    hep-phJHEP(2020)·17 citations
14. 14*

    Explaining $b\to s{\ell }^{+}{\ell }^{-}$ and the Cabibbo Angle Anomaly with a Vector Triplet

    Bernat Capdevila🇮🇹 · Andreas Crivellin🇨🇭 · Claudio Andrea Manzari🇨🇭 · Marc Montull🇨🇭

    The most statistically significant hints for new physics in the flavor sector are discrepancies between theory and experiment in $B$ decays to lepton pairs ($b\to s{\ell }^{+}{\ell }^{-}$) and a deficit in $1^{\mathrm{st}}$ row CKM unitarity (the Cabibbo Angle anomaly). We propose that these anomalies can be reconciled by a simplified model with massive gauge bosons transforming in the adjoint representation of $SU(2{)}_L$. After calculating the impact of this model on $B$ decays, observables testing charged current lepton flavor universality (LFU), electro-weak precision observables and LHC searches we perform a global fit to all available data. We find that our model can provide a consistent common explanation of both anomalies and that the fit to the data is more than $7\sigma$ better than the fit of the SM. The model also predicts interesting correlations between LFU violation in the charged current and $b\to s{\ell }^{+}{\ell }^{-}$ data which can be tested experimentally in the near future.

    hep-phhep-exhep-latnucl-ex+1PRD(2021)·81 citations
15. 15*

    Gravitational waves and proton decay: complementary windows into GUTs

    Stephen F. King🇬🇧 · Silvia Pascoli🇬🇧 · Jessica Turner🇺🇸 · Ye-Ling Zhou🇬🇧

    Proton decay is a smoking gun signature of Grand Unified Theories (GUTs). Searches by Super-Kamiokande have resulted in stringent limits on the GUT symmetry breaking scale. The large-scale multipurpose neutrino experiments DUNE, Hyper-Kamiokande and JUNO will either discover proton decay or further push the symmetry breaking scale above $10^{16}$ GeV. Another possible observational consequence of GUTs is the formation of a cosmic string network produced during the breaking of the GUT to the Standard Model gauge group. The evolution of such a string network in the expanding Universe produces a stochastic background of gravitational waves which will be tested by a number of gravitational wave detectors over a wide frequency range. We demonstrate the non-trivial complementarity between the observation of proton decay and gravitational waves produced from cosmic strings in determining $SO(10)$ GUT breaking chains. We show that such observations could exclude $SO(10)$ breaking via flipped $SU(5)\times U(1)$ or standard $SU(5)$, while breaking via a Pati-Salam intermediate symmetry, or standard $SU(5)\times U(1)$, may be favoured if a large separation of energy scales associated with proton decay and cosmic strings is indicated. We note that recent results by the NANOGrav experiment have been interpreted as evidence for cosmic strings at a scale $\sim 10^{14}$ GeV. This would strongly point towards the existence of GUTs, with $SO(10)$ being the prime candidate. We show that the combination with already available constraints from proton decay allows to identify preferred symmetry breaking routes to the Standard Model.

    hep-phastro-ph.COhep-thPRL(2021)·93 citations
16. 16*

    Light Dark Matter Annihilation and Scattering in LHC Detectors

    Martin Bauer🇬🇧 · Patrick Foldenauer🇬🇧 · Peter Reimitz🇩🇪 · Tilman Plehn🇩🇪

    We systematically study models with light scalar and pseudoscalar dark matter candidates and their potential signals at the LHC. First, we derive cosmological bounds on models with the Standard Model Higgs mediator and with a new weak-scale mediator. Next, we study two processes inspired by the indirect and direct detection process topologies, now happening inside the LHC detectors. We find that LHC can observe very light dark matter over a huge mass range if it is produced in mediator decays and then scatters with the detector material to generate jets in the nuclear recoil.

    hep-phhep-exSciPost Phys.(2021)·15 citations
17. 17*

    Electroweak baryogenesis and gravitational waves in a composite Higgs model with high dimensional fermion representations

    Ke-Pan Xie🇰🇷 · Ligong Bian🇨🇳 · Yongcheng Wu🇨🇦

    We study electroweak baryogenesis in the $SO(6)/SO(5)$ composite Higgs model with the third generation quarks being embedded in the ${\text{20}}^{\prime }$ representation of $SO(6)$. The scalar sector contains one Higgs doublet and one real singlet, and their potential is given by the Coleman-Weinberg potential evaluated from the form factors of the lightest vector and fermion resonances. We show that the resonance masses at $\mathcal{O}(1\sim 10\mathrm{TeV})$ can generate a potential that triggers the strong first-order electroweak phase transition (SFOEWPT). The $CP$ violating phase arising from the dimension-6 operator in the top sector is sufficient to yield the observed baryon asymmetry of the universe. The SFOEWPT parameter space is detectable at the future space-based detectors.

    hep-phJHEP(2020)·51 citations
18. 18*

    An eV-scale sterile neutrino search using eight years of atmospheric muon neutrino data from the IceCube Neutrino Observatory

    M. G. Aartsen🇳🇿 · R. Abbasi🇺🇸 · M. Ackermann🇩🇪 · J. Adams🇳🇿 · J. A. Aguilar🇧🇪 · M. Ahlers🇩🇰 · M. Ahrens🇸🇪 · C. Alispach🇨🇭 · N. M. Amin🇺🇸 · K. Andeen🇺🇸 · T. Anderson🇺🇸 · I. Ansseau🇧🇪 and 365 other authors

    The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305,735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01\,eV${}^2$ and 100\,eV${}^2$. The best-fit point is found to be at ${\sin }^2(2{\theta }_{24})=0.10$ and $\Delta m_{41}^2=4.5{\mathrm{eV}}^2$, which is consistent with the no sterile neutrino hypothesis with a p-value of 8.0\%.

    ↳ hep-exhep-phPRL(2020)·127 citations
19. 19*

    Searching for eV-scale sterile neutrinos with eight years of atmospheric neutrinos at the IceCube neutrino telescope

    M. G. Aartsen🇳🇿 · R. Abbasi🇺🇸 · M. Ackermann🇩🇪 · J. Adams🇳🇿 · J. A. Aguilar🇧🇪 · M. Ahlers🇩🇰 · M. Ahrens🇸🇪 · C. Alispach🇨🇭 · N. M. Amin🇺🇸 · K. Andeen🇺🇸 · T. Anderson🇺🇸 · I. Ansseau🇧🇪 and 365 other authors

    We report in detail on searches for eV-scale sterile neutrinos, in the context of a 3+1 model, using eight years of data from the IceCube neutrino telescope. By analyzing the reconstructed energies and zenith angles of 305,735 atmospheric ${\nu }_{\mu }$ and ${\bar{\nu }}_{\mu }$ events we construct confidence intervals in two analysis spaces: ${\sin }^2(2{\theta }_{24})$ vs. $\Delta m_{41}^2$ under the conservative assumption ${\theta }_{34}=0$; and ${\sin }^2(2{\theta }_{24})$ vs. ${\sin }^2(2{\theta }_{34})$ given sufficiently large $\Delta m_{41}^2$ that fast oscillation features are unresolvable. Detailed discussions of the event selection, systematic uncertainties, and fitting procedures are presented. No strong evidence for sterile neutrinos is found, and the best-fit likelihood is consistent with the no sterile neutrino hypothesis with a p-value of 8\% in the first analysis space and 19\% in the second.

    ↳ hep-exhep-phPRD(2020)·103 citations
20. 20*

    Quasiparticle properties of a single alpha particle in cold neutron matter

    Eiji Nakano🇯🇵 · Kei Iida🇯🇵 · Wataru Horiuchi🇯🇵

    Light clusters such as alpha particles and deuterons are predicted to occur in hot nuclear matter as encountered in intermediate-energy heavy-ion collisions and protoneutron stars. To examine the in-medium properties of such light clusters, we consider a much simplified system in which like an impurity, a single alpha particle is embedded in a zero-temperature, dilute gas of non-interacting neutrons. By adopting a non-selfconsistent ladder approximation for the effective interaction between the impurity and the gas, which is often used for analyses of Fermi polarons in a gas of ultracold atoms, we calculate the quasiparticle properties of the impurity, i.e., the energy shift, effective mass, quasiparticle residue, and damping rate.

    ↳ nucl-thcond-mat.quant-gashep-phPRC(2020)·19 citations
21. 21*

    Conserved charges in general relativity

    Sinya Aoki🇯🇵 · Tetsuya Onogi🇯🇵 · Shuichi Yokoyama🇯🇵

    We present a precise definition of a conserved quantity from an arbitrary covariantly conserved current available in a general curved spacetime with Killing vectors. This definition enables us to define energy and momentum for matter by the volume integral. As a result we can compute charges of Schwarzschild and BTZ black holes by the volume integration of a delta function singularity. Employing the definition we also compute the total energy of a static compact star. It contains both the gravitational mass known as the Misner-Sharp mass in the Oppenheimer-Volkoff equation and the gravitational binding energy. We show that the gravitational binding energy has the negative contribution at maximum by 68% of the gravitational mass in the case of a constant density. We finally comment on a definition of generators associated with a vector field on a general curved manifold.

    ↳ gr-qchep-phhep-thnucl-thInt.J.Mod.Phys.A(2021)·35 citations
22. 22*

    Gravitational waves from vacuum first order phase transitions II: from thin to thick walls

    Daniel Cutting🇬🇧 · Elba Granados Escartin🇫🇮 · Mark Hindmarsh🇫🇮 · David J. Weir🇫🇮

    In a vacuum first-order phase transition, gravitational waves are generated from collision of bubbles of the true vacuum. The spectrum from such collisions takes the form of a broken power law. We consider a toy model for such a phase transition, where the dynamics of the scalar field depends on a single parameter $\overline{\lambda }$, which controls how thin the bubble wall is at nucleation and how close to degenerate the vacua are relative to the barrier. We extend on our previous work by performing a series of simulations with a range of $\overline{\lambda }$. The peak of the gravitational-wave power spectrum varies by up to a factor of $1.3$, which is probably an unobservable effect. We find that the ultraviolet (UV) power law in the gravitational-wave spectrum becomes steeper as $\overline{\lambda }\to 0$, varying between $k^{-1.4}$ and $k^{-2.2}$ for the $\overline{\lambda }$ considered. This provides some evidence that the form of the underlying effective potential of a vacuum first-order phase transition could be determined from the gravitational-wave spectrum it produces.

    ↳ astro-ph.COhep-phPRD(2021)·179 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.