Mon·Jan 4, 2021Monday·January 4, 2021

1. 01*

   Triple Higgs Boson Production at the Large Hadron Collider with Two Real Singlet Scalars

   Andreas Papaefstathiou🇬🇧 · Tania Robens🇭🇷 · Gilberto Tetlalmatzi-Xolocotzi🇩🇪

   We investigate the production of three Higgs bosons in the Two Real Singlet extension of the Standard Model, where the scalar sector is augmented by two additional real scalar fields which are singlets under the Standard Model gauge group. The model contains three neutral CP-even scalars, allowing for resonant production and asymmetric decay chains. We focus on the signature $pp\to h_3\to h_1{h}_2\to h_1{h}_1{h}_1$, where we identify $h_3$ as the heaviest scalar state, $h_2$ as the second heaviest and the lightest, $h_1$, as the Standard Model-like Higgs boson discovered by the Large Hadron Collider experiments. The dominant final state occurs when all three Higgs bosons decay to bottom-anti-bottom quark pairs, $h_1\to b\bar{b}$, leading to 6 $b$-jets. Taking into account all current theoretical and experimental constraints, we determine the discovery prospects for this channel in future runs of the Large Hadron Collider, as well as in the high-luminosity phase.

   hep-phhep-exJHEP(2021)·40 citations
2. 02*

   Neutrino mass ordering obfuscated by the NSI

   Francesco Capozzi🇩🇪 · Sabya Sachi Chatterjee🇬🇧 · Antonio Palazzo🇮🇹

   Determination of the neutrino mass ordering (NMO) is one of the biggest priorities in the intensity frontier of high energy particle physics. To accomplish that goal a lot of efforts are being put together with the atmospheric, solar, reactor, and accelerator neutrinos. In the standard 3-flavor framework, NMO is defined to be normal if $m_1<m_2<m_3$, and inverted if $m_3<m_1<m_2$, where $m_1$, $m_2$, and $m_3$ are the masses of the three neutrino mass eigenstates ${\nu }_1$, ${\nu }_2$, and ${\nu }_3$ respectively. Interestingly, two long-baseline experiments T2K and NO$\nu$A are playing a leading role in this direction and provide a $\sim 2.4\sigma$ indication in favor of normal ordering (NO) which we find in this work. In addition, we examine how the situation looks like in presence of non-standard interactions (NSI) of neutrinos with a special focus on the non-diagonal flavor changing type ${\epsilon }_{e\tau }$ and ${\epsilon }_{e\mu }$. We find that the present indication of NO in the standard 3-flavor framework gets completely vanished in the presence of NSI of the flavor changing type involving the $e-\tau$ flavors.

   hep-phhep-exhep-thPoS(2021)·1 citation
3. 03*

   The Mystery of Bloom-Gilman Duality: A Light Front Holographic QCD Perspective

   Aiden B. Sheckler🇺🇸 · Gerald A. Miller🇺🇸

   Light front wave functions motivated by holographic constructions are used to study Bloom-Gilman duality of deep inelastic scattering. Separate expressions for structure functions in terms of quark and hadronic degrees of freedom are presented, with a goal of relating the two expressions. A two-parton model is defined and resonance transition form factors are computed using previously derived light front wave functions. A new form of global duality is derived from the valence quark-number sum rule. Using a complete set of hadronic states is necessary for this new global duality to be achieved. Previous original work does not provide such a set. This is remedied by amending the model to include a longitudinal confining potential, and the resulting complete set is sufficient to carry out the study of Bloom-Gilman duality. Expressions for transition form factors are obtained and all are shown to fall asymptotically as 1/Q2. The Feynman mechanism dominates the asymptotic behavior of the model. These transition form factors are used to assess the validity of the global and local duality sum rules, with the result that both neither are satisfied. Evaluations of the hadronic expression for q(x,Q2) provide more details about this lack. This result shows that the observed validity of both global and local forms of duality for deep inelastic scattering must be related to a feature of QCD that is deeper than completeness. Our simple present model suggests a prediction that Bloom-Gilman duality would not be observed if deep inelastic scattering experiments were to be made on the pion. The underlying origin of the duality phenomenon in deep inelastic scattering is deeply buried within the confinement aspects of QCD, and remains a mystery.

   hep-phnucl-exnucl-thPRD(2021)·7 citations
4. 04*

   Resonant Scattering between Dark Matter and Baryons: Revised Direct Detection and CMB Limits

   Xingchen Xu🇺🇸 · Glennys R. Farrar🇺🇸

   Traditional dark matter models, eg. WIMPs, assume dark matter is weakly coupled to the standard model so that elastic scattering between dark matter and baryons can be described perturbatively by Born approximation. Most direct detection experiments are analyzed according to that assumption. We show that when the fundamental DM-baryon interaction is attractive, dark matter-nucleus scattering is non-perturbative in much of the relevant parameter range. The cross section exhibits rich resonant behavior with a highly non-trivial dependence on atomic mass; furthermore, the extended rather than point-like nature of nuclei significantly impacts the cross sections. The repulsive case also requires full numerical calculation. These non-perturbative effects change existing constraints. Near a resonance value of the parameters, the cross section has non-trivial velocity dependence rather than the usual $\sigma \sim v^0$; we take the velocity dependence into account. (However doing so has little impact on current constraints.) We report the corrected exclusion regions superseding previous limits from XQC, CRESST Surface Run, CMB power spectrum and extensions with Lyman-$\alpha$ and Milky Way satellites, and Milky Way gas clouds. Some limits become weaker than previous bounds in the literature, while others become stronger. Gaps which open by correct treatment of some particular constraint can sometimes be closed using a different constraint. We also discuss the dependence on mediator mass and give approximate expressions for the velocity dependence near a resonance. Sexaquark ($uuddss$) DM with mass around 2 GeV, which exchanges QCD mesons with baryons, remains unconstrained for most of the parameter space of interest. A statement in the literature that a DM-nucleus cross section larger than $10^{-25}{\mathrm{cm}}^2$ implies dark matter is composite, is corrected.

   hep-phastro-ph.COastro-ph.HEhep-exPRD(2023)·34 citations
5. 05*

   The Sun: Light Dark Matter and Sterile Neutrinos

   Ilídio Lopes🇵🇹

   Next-generation experiments allow for the possibility to testing the neutrino flavor oscillation model to very high levels of accuracy. Here, we explore the possibility that the dark matter in the current universe is made of two particles, a sterile neutrino and a very light dark matter particle. By using a 3+1 neutrino flavor oscillation model, we study how such a type of dark matter imprints the solar neutrino fluxes, spectra, and survival probabilities of electron neutrinos. The current solar neutrino measurements allow us to define an upper limit for the ratio of the mass of a light dark matter particle $m_{\varphi }$ and the Fermi constant $G_{\varphi }$, such that $G_{\varphi }/m_{\varphi }$ must be smaller than $10^{30}{G}_{\mathrm{F}}e{V}^{-1}$ to be in agreement with current solar neutrino data from the Borexino, Sudbury Neutrino Observatory, and Super-Kamiokande detectors. Moreover, for models with a very small Fermi constant, the amplitude of the time variability must be lower than $3\%$ to be consistent with current solar neutrino data. We also found that solar neutrino detectors like Darwin, able to measure neutrino fluxes in the low energy-range with high accuracy, will provide additional constraints to this class of models that complement the ones obtained from the current solar neutrino detectors.

   hep-phastro-ph.COastro-ph.SRhep-ex+1ApJ(2020)·9 citations
6. 06*

   Neutrinoless double beta decay without Majorana neutrinos

   Pei-Hong Gu🇨🇳

   It is firmly believed that a signal of neutrinoless double beta decay can unquestionably confirm the Majorana nature of neutrinos. However we notice that a Majorana neutrino mass induced after some neutrinoless double beta decay processes can be accidentally cancelled by another Majorana neutrino mass induced before any neutrinoless double beta decay processes. This realistic cancellation can simultaneously allow an observable neutrinoless double beta decay and a vanishing Majorana neutrino mass. In consequence a future discovery of neutrinoless double beta decay cannot fully rule out the possibility of Dirac neutrinos.

   hep-phPLB(2021)·1 citation
7. 07*

   New phenomena in laser-assisted leptonic decays of the negatively charged boson $W^{-}$

   S. Mouslih🇲🇦 · M. Jakha🇲🇦 · I. Dahiri🇲🇦 · S. Taj🇲🇦 · B. Manaut🇲🇦 · E. Siher🇲🇦

   In this paper and within the standard Glashow-Weinberg-Salam model of electroweak interactions, we study theoretically the leptonic decay of the $W^{-}$-boson $(W^{-}\to {\ell }^{-}{\bar{\nu }}_{\ell })$ in the presence of a circularly polarized electromagnetic field and we examine the laser effect, in terms of its field strength and frequency, on the leptonic decay rate and the phenomenon of multiphoton processes. The calculations are carried out using the exact relativistic wave functions of charged particles in an electromagnetic field. It was found that the laser significantly contributed to reducing the probability of $W^{-}$-boson decay. We show that the laser-assisted decay rate is equal to the laser-free one only when the famous Kroll-Watson sum rule is fulfilled. The notable effect of the laser on the leptonic decay rate was reasonably interpreted by the well-known quantum Zeno effect or by the opening of channels other than leptonic ones to decay. We hope that this article paved the way for an upcoming paper to study the hadronic decay of the $W^{-}$-boson and then explore the laser effect on its lifetime and branching ratios.

   hep-phPhys.Scripta(2022)·10 citations
8. 08*

   A matter of shape: seeing the deformation of atomic nuclei at high-energy colliders

   Giuliano Giacalone🇫🇷

   This work establishes a deep connection between two seemingly distant branches of nuclear physics: nuclear structure and relativistic heavy-ion collisions. At the heart of this connection is the recent discovery made at particle colliders that the elliptic flow of outgoing hadrons in central nucleus-nucleus collisions is strongly impacted by the quadrupole deformation of the colliding nuclear species. I review the physics of the soft sector of relativistic heavy-ion collisions, and I explain that the interpretation of elliptic flow data in central ${}^{197}$Au+${}^{197}$Au, ${}^{238}$U+${}^{238}$U, and ${}^{129}$Xe+${}^{129}$Xe collisions requires a deep understanding the structure of these ions. Subsequently, I introduce a technique that permits one to isolate collision configurations in which the deformed shapes of the colliding nuclei maximally break rotational (azimuthal) symmetry in the interaction region. This allows me to construct observables that possess an unparalleled sensitivity to the quadrupole deformation of the colliding ions, and thus to conclude that nuclear experiments at high energy can be used to place new quantitative constraints on the deformation of atomic nuclei. I emphasize the great opportunities offered by potential collider experiments aimed at the systematic study of nuclear deformation across the valley of stability.

   ↳ nucl-thhep-exhep-phnucl-ex24 citations
9. 09*

   Curing inflationary degeneracies using reheating predictions and relic gravitational waves

   Swagat S. Mishra🇮🇳 · Varun Sahni🇮🇳 · Alexei A. Starobinsky🇷🇺

   It is well known that the inflationary scenario often displays different sets of degeneracies in its predictions for CMB observables. These degeneracies usually arise either because multiple inflationary models predict similar values for the scalar spectral index $n_{{}_S}$ and the tensor-to-scalar ratio $r$, or because within the same model, the values of $\{n_{{}_S},r\}$ are insensitive to some of the model parameters, making it difficult for CMB observations alone to constitute a unique probe of inflationary cosmology. We demonstrate that by taking into account constraints on the post-inflationary reheating parameters such as the duration of reheating $N_{{}_{\mathrm{re}}}$, its temperature $T_{{}_{\mathrm{re}}}$ and especially its equation of state (EOS), $w_{{}_{\mathrm{re}}}$, it is possible to break this degeneracy in certain classes of inflationary models where identical values of $\{n_{{}_S},r\}$ can correspond to different reheating $w_{{}_{\mathrm{re}}}$. In particular, we show how reheating constraints can break inflationary degeneracies in the T-model and the E-model $\alpha$-attractors. Non-canonical inflation is also studied. The relic gravitational wave (GW) spectrum provides us with another tool to break inflationary degeneracies. This is because the GW spectrum is sensitive to the post-inflationary EOS of the universe. Indeed a stiff EOS during reheating $(w_{{}_{\mathrm{re}}}>1/3)$ gives rise to a small scale blue tilt in the spectral index $n_{{}_{\mathrm{GW}}}=\frac{d\log {\Omega }_{{}_{\mathrm{GW}}}}{d\log k}>0$, while a soft EOS $(w_{{}_{\mathrm{re}}}<1/3)$ results in a red tilt. Relic GWs therefore provide us with valuable information about the post-inflationary epoch, and their spectrum can be used to cure inflationary degeneracies in $\{n_{{}_S},r\}$.

   ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2021)·75 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.