Thu·Apr 29, 2021Thursday·April 29, 2021

1. 01*

   The simplest scoto-seesaw model: WIMP dark matter phenomenology and Higgs vacuum stability

   Sanjoy Mandal🇪🇸 · Rahul Srivastava🇮🇳 · José W. F. Valle🇪🇸

   We analyze the consistency of electroweak breaking, neutrino and dark matter phenomenology within the simplest scoto-seesaw model. By adding the minimal dark sector to the simplest "missing partner" type-I seesaw one has a physical picture for the neutrino oscillation lengths: the "atmospheric" mass scale arises from the tree-level seesaw, while the "solar" scale is induced radiatively, mediated by the dark sector. We identify parameter regions consistent with theoretical constraints, as well as dark matter relic abundance and direct detection searches. Using two-loop renormalization group equations we explore the stability of the vacuum and the consistency of the underlying dark parity symmetry. One also has a lower bound for the neutrinoless double beta decay amplitude.

   hep-phhep-exPLB(2021)·44 citations
2. 02*

   Dark Matter Phenomenology: Sterile Neutrino Portal and Gravitational Portal in Extra-Dimensions

   Miguel G. Folgado🇪🇸

   The Standard Model of Fundamental Interactions (SM) represents one of the most precise theories in physics. Among the predictions of the SM we find, for instance, the anomalous magnetic moment of the electron $a_e=0.001159652181643(764)$. This prediction agrees with the experimental results to more than ten significant digits, the most accurate prediction in the history of physics. However, nowadays we have several evidences that the SM only explains $5\%$ of the matter content of the Universe. The other $95\%$ are composed by the so-called Dark Energy and Dark Matter. As their names suggest, the nature of these two components of the energy/matter content of the Universe is still unclear and represents one of the most important challenges for the particle physicists. In this Thesis we have focused in the study of the phenomenology of one of these mysterious components of the Universe, the Dark Matter. Although we have many evidences of its existence, this new type of matter has not been detected yet. As a consequence, the landscape of the models that can explain the Dark Matter properties is huge. In the present work we propose and study several Dark Matter models, setting limits by using experimental results.

   hep-phastro-ph.HE0 citations
3. 03*

   Transverse momentum dependent parton densities in processes with heavy quark generations

   A.V. Kotikov🇷🇺 · A.V. Lipatov🇷🇺 · P. Zhang🇨🇳

   To study the heavy quark production processes, we use the transverse momentum dependent (TMD, or unintegrated) gluon distribution function in a proton obtained recently using the Kimber-Martin-Ryskin prescription from the Bessel-inspired behavior of parton densities at small Bjorken $x$ values. We obtained a good agreement of our results with the latest HERA experimental data for reduced cross sections ${\sigma }_{\mathrm{red}}^{c\overline{c}}(x,Q^2)$ and ${\sigma }_{\mathrm{red}}^{b\overline{b}}(x,Q^2)$, and also for deep inelastic structure functions $F_2^c(x,Q^2)$ and $F_2^b(x,Q^2)$ in a wide range of $x$ and $Q^2$ values. Comparisons with the predictions based on the Ciafaloni-Catani-Fiorani-Marchesini evolution equation and with the results of conventional pQCD calculations performed at first three orders of perturbative expansion are presented.

   hep-phPRD(2021)·22 citations
4. 04*

   Radial oscillations in neutron stars from QCD

   José C. Jiménez🇧🇷 · Eduardo S. Fraga🇧🇷

   We study the stability against infinitesimal radial oscillations of neutron stars generated by a set of equations of state obtained from first-principle calculations in cold and dense QCD and constrained by observational data. We consider mild and large violations of the conformal bound, $c_s=1/\sqrt{3}$, in stars that can possibly contain a quark matter core. Some neutron star families in the mass-radius diagram become dynamically unstable due to large oscillation amplitudes near the core.

   hep-phastro-ph.HEgr-qcnucl-thPRD(2021)·15 citations
5. 05*

   Pseudo-Nambu-Goldstone Dark Matter Model Inspired by Grand Unification

   Yoshihiko Abe🇯🇵 · Takashi Toma🇯🇵 · Koji Tsumura🇯🇵 · Naoki Yamatsu🇯🇵

   A pseudo-Nambu-Goldstone boson (pNGB) is an attractive candidate for dark matter (DM) due to the simple evasion of the current severe limits of DM direct detection experiments. One of the pNGB DM models has been proposed based on a {\it gauged} $U(1{)}_{B-L}$ symmetry. The pNGB has long enough lifetime to be a DM and thermal relic abundance of pNGB DM can be fit with the observed value against the constraints on the DM decays from the cosmic-ray observations. The pNGB DM model can be embedded into an $SO(10)$ pNGB DM model in the framework of an $SO(10)$ grand unified theory, whose $SO(10)$ is broken to the Pati-Salam gauge group at the unified scale, and further to the Standard Model gauge group at the intermediate scale. Unlike the previous pNGB DM model, the parameters such as the gauge coupling constants of $U(1{)}_{B-L}$, the kinetic mixing parameter of between $U(1{)}_Y$ and $U(1{)}_{B-L}$ are determined by solving the renormalization group equations for gauge coupling constants with appropriate matching conditions. From the constraints of the DM lifetime and gamma-ray observations, the pNGB DM mass must be less than $\mathcal{O}(100)$GeV. We find that the thermal relic abundance can be consistent with all the constraints when the DM mass is close to half of the CP even Higg masses.

   hep-phPRD(2021)·32 citations
6. 06*

   CP violation in quasi-two-body $D\to VP$ decays and three-body $D$ decays mediated by vector resonances

   Hai-Yang Cheng🇹🇼 · Cheng-Wei Chiang🇹🇼

   We re-examine direct CP violation in the quasi-two-body $D\to VP$ decays and study CP asymmetries in three-body $D$ decays proceeding through intermediate vector resonances within the framework of the topological amplitude approach for tree amplitudes and the QCD factorization approach for penguin amplitudes. Using the same mechanism of incorporating long-distance penguin-exchange amplitude induced from final-state rescattering that nicely accounts for the CP asymmetry difference between $D^0\to K^{+}{K}^{-}$ and ${\pi }^{+}{\pi }^{-}$ modes, we find that CP asymmetry can also occur at the per mille level in many of the $D\to VP$ channels or otherwise be negligibly small. We point out six golden modes which have sufficiently large branching fractions and direct CP violation of order $10^{-3}$. In particular, the direct CP asymmetry difference $\Delta a_{CP}^{VP}$ between $D^0\to K^{+}{K}^{\ast -}$ and ${\pi }^{+}{\rho }^{-}$ is predicted to be $(-1.61\pm 0.33)\times 10^{-3}$, very similar to the counterpart in the $PP$ sector. Besides, we find a positive and large CP asymmetry of order $10^{-3}$ in $D^0\to K_S{K}^{\ast 0}$, an example of the asymmetry induced at the tree level. We take into account the flavor-singlet QCD-penguin contributions to calculate their effects on the modes such as $D\to \pi \varphi$ and $D\to \eta \varphi$. We compare our results with the other approach in detail. For three-body $D$ decays, we perform the Dalitz plot analysis of those decays mediated by several vector resonances with the same mass but different electric charges. Local CP asymmetry varies in magnitude and sign from region to region and can reach the percent level in certain local regions of phase space due to interference.

   hep-phhep-exPRD(2021)·45 citations
7. 07*

   Veltman, renormalizability, calculability

   Giampiero Passarino🇮🇹

   Dedicated to the memory of Prof. Veltman, one of the founding fathers of our discipline: his legacy lives on. Many times we have to turn back and follow his footprints to find the right path. After reviewing general aspects of high energy physics where he gave a seminal contribution we will introduce recent developments in the standard model effective field theory, showing how the whole movement from renormalization to predictions plays from Veltman to SMEFT.

   hep-phhep-thActa Phys.Polon.B(2021)·8 citations
8. 08*

   Displaced Neutrino Jets at the LHeC

   Giovanna Cottin🇨🇱 · Oliver Fischer🇬🇧 · Sanjoy Mandal🇪🇸 · Manimala Mitra🇮🇳 · Rojalin Padhan🇮🇳

   Extending the Standard Model with right-handed neutrinos (RHNs) is well motivated by the observation of neutrino oscillations. In the type-I seesaw model, the RHNs interact with the SM particles via tiny mixings with the active neutrinos, which makes their discovery in the laboratory, and in particular at collider experiments in general challenging. In this work we instead consider an extension of the type-I seesaw model with the addition of a leptoquark (LQ), and employ a non-minimal production mechanism of the RHN via LQ decay, which is unsuppressed by neutrino mixing. We focus on relatively light RHN with mass $\mathcal{O}(10)$ GeV and LQ with mass 1.0 TeV, and explore the discovery prospect of the RHN at the proposed Large Hadron electron Collider. In the considered mass range and with the given interaction strength, the RHN is long lived and, due to it stemming from the LQ decay, it is also heavily boosted, resulting in collimated decay products. The unique signature under investigation is thus a displaced fat jet. We use kinematic variables to separate signal from background, and demonstrate that the ratio variables with respect to energy/number of displaced and prompt tracks are useful handles in the identification of displaced decays of the RHN. We also show that employing a positron beam provides order of magnitude enhancement in the detection prospect of this signature.

   hep-phJHEP(2022)·20 citations
9. 09*

   Beyond freeze-in: Dark Matter via inverse phase transition and gravitational wave signal

   S. Ramazanov🇨🇿 · E. Babichev🇫🇷 · D. Gorbunov🇷🇺 · A. Vikman🇨🇿

   We propose a novel scenario of Dark Matter production naturally connected with generation of gravitational waves. Dark Matter is modelled as a real scalar, which interacts with the hot primordial plasma through a portal coupling to another scalar field. For a particular sign of the coupling, this system exhibits an inverse second order phase transition. The latter leads to an abundant Dark Matter production, even if the portal interaction is so weak that the freeze-in mechanism is inefficient. The model predicts domain wall formation in the Universe, long time before the inverse phase transition. These domain walls have a tension decreasing with time, and completely disappear at the inverse phase transition, so that the problem of overclosing the Universe is avoided. The domain wall network emits gravitational waves with characteristics defined by those of Dark Matter. In particular, the peak frequency of gravitational waves is determined by the portal coupling constant, and falls in the observable range for currently planned gravitational wave detectors.

   hep-phastro-ph.COgr-qchep-thPRD(2022)·51 citations
10. 10*

    Trimaximal mixing with one texture zero from type II seesaw and $\Delta (54)$ family symmetry

    M. A. Loualidi🇲🇦

    We propose a neutrino model based on a $\Delta (54)$ flavor symmetry suitable for explaining the current neutrino oscillation data. Neutrino masses arise from the type II seesaw mechanism where the $\Delta (54)$ field assignments has led to a simple neutrino mass matrix with one texture zero and which satisfies the magic symmetry consistent with the well-known trimaximal mixing matrix. We found interesting predictions concerning neutrino masses and mixing. In particular, only the normal neutrino mass hierarchy and the lower octant of the atmospheric angles are allowed in this model. The model predicts as well that the $CP$ conserving values for the Dirac $CP$ phase ${\delta }_{CP}$ are not allowed and thus, $CP$ is always violated in the neutrino sector. We have also investigated the sum of absolute neutrino masses from cosmological observations, the effective Majorana mass $m_{\beta \beta }$\ from neutrinoless double beta decay experiments, and the electron neutrino mass $m_{\beta }$\ from beta decays where we found that the obtained range of $m_{\beta \beta }$\ can be tested by several experiments in the near future.

    hep-ph9 citations
11. 11*

    Quarkonium interactions with (hot) hadronic matter

    Luciano M. Abreu🇧🇷 · Hildeson P. L. Vieira🇧🇷

    In this work, we present an updated study about the interactions of quarkonia with surrounding hadronic medium. The meson-meson interactions are described with a chiral effective Lagrangian within the framework of unitarized coupled channel amplitudes. In particular, we extend a previous work performed in the charmonium sector by calculating the cross-sections for ${\rm Y}$ scattering by light pseudoscalar mesons ($\pi ,K,\eta$) and vector mesons ($\rho ,K^{\ast },\omega$). We evaluate the relevant channels and compare the results with existing literature. The analysis is completed by including the finite-temperature effects in the unitarized scattering amplitudes for both quarkonium and bottomonium sectors.

    hep-phEPJA(2021)·3 citations
12. 12*

    Light vector dark matter with scalar mediator and muon g-2 anomaly

    Karim Ghorbani🇮🇷

    We study a model with a vector dark matter (DM) candidate interacting with the SM charged leptons through a scalar portal. The dark matter candidate acquires mass when the complex scalar breaks an abelian gauge symmetry spontaneously. The scalar interacts with the SM charged leptons through a dimension-6 operator. The scalar mediator induces elastic scattering of dark matter with electrons at tree level and also DM-nucleon interaction when the effects from scalar-Higgs mixing are also taken into account. Given the recent results from Xenon1T upper bounds on DM-electron elastic scattering cross section where the strongest sensitivity lies in the range $\sim \mathcal{O}$(1) GeV, we find the viable space in the parameter space respecting constraints from the observed relic density, direct detection, muon $(g_{\mu }-2)$ anomaly, $e^{+}{e}^{-}$ colliders, electron beam-dump experiments and astrophysical observables. It is shown that the current upper bounds of Xenon1T on DM-electron interaction is partially sensitive to the regions in the viable parameter space which is already excluded by the electron beam-dump experiment, Orsay. We also find that there are viable DM particles with masses $\sim \mathcal{O}(1)$ GeV evading the direct detection but stand well above the neutrino floor. Almost the same viable regions are found when we apply the direct detection upper limits on the DM-proton spin-independent cross section.

    hep-phPRD(2021)·19 citations
13. 13*

    Novel Higgsino Dark Matter Signatures at the LHC

    Ernesto Arganda🇪🇸 · Antonio Delgado🇺🇸 · Roberto A. Morales🇪🇸 · Mariano Quirós🇪🇸

    In the LHC searches for gluinos it is usually assumed that they decay predominantly into the lightest neutralino plus jets. In this work we perform a proof-of-concept collider analysis of a novel supersymmetric signal in which gluinos decay mostly into jets and the bino-like neutralino (${\tilde{\chi }}_3^0$), which in turn decays into the lightest Higgsino-like neutralino (${\tilde{\chi }}_1^0$), considered the dark matter candidate, together with the SM-like Higgs boson ($h$). This new physics signal then consists of an LHC final state made up by four light jets, four $b$-jets, and a large amount of missing transverse energy. We identify $t\bar{t}$, $V$+jets ($V$= $W$, $Z$), and $t\bar{t}+X$ ($X$ = $W$, $Z$, ${\gamma }^{\ast }$, $h$) productions as the most problematic backgrounds, and develop a search strategy for the high luminosity phase of the LHC, reaching signal significances at the evidence level for a luminosity of 1000 fb${}^{-1}$. The prospects for a luminosity of 3000 fb${}^{-1}$ are even more promising, with discovery-level significances.

    hep-phhep-exPRD(2021)·5 citations
14. 14*

    Revisiting isocurvature bounds in models unifying the axion with the inflaton

    Guillermo Ballesteros🇪🇸 · Andreas Ringwald🇩🇪 · Carlos Tamarit🇩🇪 · Yvette Welling🇩🇪

    Axion scenarios in which the spontaneous breaking of the Peccei-Quinn symmetry takes place before or during inflation, and in which axion dark matter arises from the misalignment mechanism, can be constrained by Cosmic Microwave Background isocurvature bounds. Dark matter isocurvature is thought to be suppressed in models with axion-inflaton interactions, for which axion perturbations are assumed to freeze at horizon crossing during inflation. However, this assumption can be an oversimplification due to the interactions themselves. In particular, non-perturbative effects during reheating may lead to a dramatic growth of axion perturbations. We perform lattice calculations in two models in which the Peccei-Quinn field participates in inflation. We find that the growth of axion perturbations is such that the Peccei-Quinn symmetry is restored for an axion decay constant $f_A\lesssim 10^{16}$-$10^{17}$ GeV, leading to an over-abundance of dark matter, unless $f_A\lesssim 2\times 10^{11}$ GeV. For $f_A\gtrsim 10^{16}$-$10^{17}$ GeV we still find a large growth of axion perturbations at low momentum, such that a naive extrapolation to CMB scales suggests a violation of the isocurvature bounds.

    hep-phastro-ph.COJCAP(2021)·17 citations
15. 15*

    Millicharged Particles from the Heavens: Single- and Multiple-Scattering Signatures

    Carlos A. Argüelles🇺🇸 · Kevin J. Kelly🇺🇸 · Víctor M. Muñoz🇪🇸

    For nearly a century, studying cosmic-ray air showers has driven progress in our understanding of elementary particle physics. In this work, we revisit the production of millicharged particles in these atmospheric showers and provide new constraints for XENON1T and Super-Kamiokande and new sensitivity estimates of current and future detectors, such as JUNO. We discuss distinct search strategies, specifically studies of single-energy-deposition events, where one electron in the detector receives a relatively large energy transfer, as well as multiple-scattering events consisting of (at least) two relatively small energy depositions. We demonstrate that these atmospheric search strategies -- especially this new, multiple-scattering signature -- provide significant room for improvement in the next decade, in a way that is complementary to anthropogenic, beam-based searches for MeV-GeV millicharged particles. Finally, we also discuss the implementation of a Monte Carlo simulation for millicharged particle detection in large-volume neutrino detectors, such as IceCube.

    hep-phhep-exJHEP(2021)·61 citations
16. 16*

    Turbulent axion-photon conversions in the Milky-Way

    Pierluca Carenza🇮🇹 · Carmelo Evoli🇮🇹 · Maurizio Giannotti🇺🇸 · Alessandro Mirizzi🇮🇹 · Daniele Montanino🇮🇹

    The Milky-Way magnetic field can trigger conversions between photons and axion-like particles (ALPs), leading to peculiar features on the observable photon spectra. Previous studies considered only the regular component of the magnetic field. However, observations consistently show the existence of an additional turbulent component, with a similar strength and correlated on a scale of a few 10pc. We investigate the impact of the turbulent magnetic field on the ALP-photon conversions, characterizing the effects numerically and analytically. We show that the turbulent magnetic field can change the conversion probability by up to a factor of two and may lead to observable irregularities in the observable photon spectra from different astrophysical sources.

    hep-phastro-ph.HEPRD(2021)·42 citations
17. 17*

    Testing freeze-in with axial and vector $Z^{\prime }$ bosons

    Catarina Cosme🇨🇦 · Maíra Dutra🇨🇦 · Stephen Godfrey🇨🇦 · Taylor R. Gray🇨🇦

    The freeze-in production of Feebly Interacting Massive Particle (FIMP) dark matter in the early universe is an appealing alternative to the well-known - and constrained - Weakly Interacting Massive Particle (WIMP) paradigm. Although challenging, the phenomenology of FIMP dark matter has been receiving growing attention and is possible in a few scenarios. In this work, we contribute to this endeavor by considering a $Z^{\prime }$ portal to fermionic dark matter, with the $Z^{\prime }$ having both vector and axial couplings and a mass ranging from MeV up to PeV. We evaluate the bounds on both freeze-in and freeze-out from direct detection, atomic parity violation, leptonic anomalous magnetic moments, neutrino-electron scattering, collider, and beam dump experiments. We show that FIMPs can already be tested by most of these experiments in a complementary way, whereas WIMPs are especially viable in the $Z^{\prime }$ low mass regime, in addition to the $Z^{\prime }$ resonance region. We also discuss the role of the axial couplings of $Z^{\prime }$ in our results. We therefore hope to motivate specific realizations of this model in the context of FIMPs, as well as searches for these elusive dark matter candidates.

    hep-phastro-ph.COastro-ph.HEhep-thJHEP(2021)·18 citations
18. 18*

    Towards massless and massive event shapes in the large-${\beta }_0$ limit

    Néstor G. Gracia🇪🇸 · Vicent Mateu🇪🇸

    We present results for SCET and bHQET matching coefficients and jet functions in the large-${\beta }_0$ limit. Our computations exactly predict all terms of the form ${\alpha }_s^{n+1}{n}_f^n$ for any $n\ge 0$, and we find full agreement with the coefficients computed in the full theory up to $\mathcal{O}({\alpha }_s^4)$. We obtain all-order closed expressions for the cusp and non-cusp anomalous dimensions (which turn out to be unambiguous) as well as matrix elements (with ambiguities) in this limit, which can be easily expanded to arbitrarily high powers of ${\alpha }_s$ using recursive algorithms to obtain the corresponding fixed-order coefficients. Examining the poles laying on the positive real axis of the Borel-transform variable $u$ we quantify the perturbative convergence of a series and estimate the size of non-perturbative corrections. We find a so far unknown $u=1/2$ renormalon in the bHQET hard factor $H_m$ that affects the normalization of the peak differential cross section for boosted top quark pair production. For ambiguous series the so-called Borel sum is defined with the principal value prescription. Furthermore, one can assign an ambiguity based on the arbitrariness of avoiding the poles by contour deformation into the positive or negative imaginary half-plane. Finally, we compute the relation between the pole mass and four low-scale short distance masses in the large-${\beta }_0$ approximation (MSR, RS and two versions of the jet mass), work out their $\mu$- and $R$-evolution in this limit, and study how their implementation improves the convergence of the position-space bHQET jet function, whose three-loop coefficient in full QCD is numerically estimated.

    hep-phJHEP(2021)·23 citations
19. 19*

    Quark masses using twisted mass fermion gauge ensembles

    C. Alexandrou🇨🇾 · S. Bacchio🇨🇾 · G. Bergner🇩🇪 · M. Constantinou🇺🇸 · M. Di Carlo🇬🇧 · P. Dimopoulos🇮🇹 · J. Finkenrath🇨🇾 · E. Fiorenza🇩🇰 · R. Frezzotti🇮🇹 · M. Garofalo🇩🇪 · K. Hadjiyiannakou🇨🇾 · B. Kostrzewa🇩🇪 and 15 other authors

    We present a calculation of the up, down, strange and charm quark masses performed within the lattice QCD framework. We use the twisted mass fermion action and carry out simulations that include in the sea two light mass-degenerate quarks, as well as the strange and charm quarks. In the analysis we use gauge ensembles simulated at three values of the lattice spacing and with light quarks that correspond to pion masses in the range from 350 MeV to the physical value, while the strange and charm quark masses are tuned approximately to their physical values. We use several quantities to set the scale in order to check for finite lattice spacing effects and in the continuum limit we get compatible results. The quark mass renormalization is carried out non-perturbatively using the RI'-MOM method converted into the $\overline{\mathrm{MS}}$ scheme. For the determination of the quark masses we use physical observables from both the meson and the baryon sectors, obtaining $m_{ud}=3.636(66){(}_{-57}^{+60})$~MeV and $m_s=98.7(2.4){(}_{-3.2}^{+4.0})$~MeV in the $\overline{\mathrm{MS}}(2\mathrm{GeV})$ scheme and $m_c=1036(17){(}_{-8}^{+15})$~MeV in the $\overline{\mathrm{MS}}(3\mathrm{GeV})$ scheme, where the first errors are statistical and the second ones are combinations of systematic errors. For the quark mass ratios we get $m_s/m_{ud}=27.17(32){(}_{-38}^{+56})$ and $m_c/m_s=11.48(12){(}_{-19}^{+25})$.

    ↳ hep-lathep-phPRD(2021)·97 citations
20. 20*

    Spectral representation of the shear viscosity for local scalar QFTs at finite temperature

    Peter Lowdon🇩🇪 · Ralf-Arno Tripolt🇦🇹 · Jan M. Pawlowski🇩🇪 · Dirk H. Rischke🇩🇪

    In local scalar quantum field theories (QFTs) at finite temperature correlation functions are known to satisfy certain non-perturbative constraints, which for two-point functions in particular implies the existence of a generalisation of the standard Källén-Lehmann representation. In this work, we use these constraints in order to derive a spectral representation for the shear viscosity arising from the thermal asymptotic states, ${\eta }_0$. As an example, we calculate ${\eta }_0$ in ${\varphi }^4$ theory, establishing its leading behaviour in the small and large coupling regimes.

    ↳ hep-thhep-phnucl-thPRD(2021)·12 citations
21. 21*

    CNNs for enhanced background discrimination in DSNB searches in large-scale water-Gd detectors

    David Maksimović🇩🇪 · Michael Nieslony🇩🇪 · Michael Wurm🇩🇪

    Gadolinium-loading of large water Cherenkov detectors is a prime method for the detection of the Diffuse Supernova Neutrino Background (DSNB). While the enhanced neutron tagging capability greatly reduces single-event backgrounds, correlated events mimicking the IBD coincidence signature remain a potentially harmful background. Neutral-Current (NC) interactions of atmospheric neutrinos potentially dominate the DSNB signal especially in the low-energy range of the observation window that reaches from about 12 to 30 MeV. The present paper investigates a novel method for the discrimination of this background. Convolutional Neural Networks (CNNs) offer the possibility for a direct analysis and classification of the PMT hit patterns of the prompt events. Based on the events generated in a simplified SuperKamiokande-like detector setup, we find that a trained CNN can maintain a signal efficiency of 96 % while reducing the residual NC background to 2 % of the original rate. Comparing to recent predictions of the DSNB signal and measurements of the NC background levels in Super-Kamiokande, the corresponding signal-to-background ratio is about 4:1, providing excellent conditions for a DSNB discovery.

    ↳ physics.ins-detastro-ph.IMhep-exhep-phJCAP(2021)·20 citations
22. 22*

    Variational symmetries and superintegrability in multifield cosmology

    Alex Giacomini🇨🇱 · Esteban González🇨🇱 · Genly Leon🇨🇱 · Andronikos Paliathanasis🇿🇦

    We consider a spatially flat Friedmann--Lema\^ıtre--Robertson--Walker background space with an ideal gas and a multifield Lagrangian consisting of two minimally coupled scalar fields which evolve in a field space of constant curvature. For this cosmological model we classify the potential function for the scalar fields such that variational point symmetries exist. The corresponding conservation laws are calculated. Finally, analytic solutions are presented for specific functional forms of the scalar field potential in which the cosmological field equations are characterized as a Liouville integrable system by point symmetries. The free parameters of the cosmological model are constrained in order to describe analytic solutions for an inflationary epoch. Finally, stability properties of exact closed-form solutions are investigated. These solutions are scaling solutions with important physical properties for the cosmological model.

    ↳ gr-qchep-phmath-phmath.MPPRD(2022)·8 citations
23. 23*

    The sound speed and core of massive compact stars: A manifestation of hadron-quark duality

    Yong-Liang Ma🇨🇳 · Mannque Rho🇫🇷

    When baryon-quark continuity is formulated in terms of a topology change without invoking "explicit " QCD degrees of freedom at a density higher than twice the nuclear matter density $n_0$ the core of massive compact stars can be described in terms of fractionally charged particles, behaving neither like pure baryons nor deconfined quarks. Hidden symmetries, both local gauge and pseudo-conformal (or broken scale), lead to the pseudo-conformal (PC) sound velocity $v_{pcs}^2/c^2\approx 1/3$ at $\text{gsim}3n_0$ in compact stars. We argue these symmetries are "emergent" from strong nuclear correlations and conjecture that they reflect hidden symmetries in QCD proper exposed by nuclear correlations. We establish a possible link between the quenching of $g_A$ in superallowed Gamow-Teller transitions in nuclei and the precocious onset at $n\text{gsim}3n_0$ of the PC sound velocity predicted at the dilaton limit fixed point. We propose that bringing in explicit quark degrees of freedom as is done in terms of the "quarkyonic" and other hybrid hadron-quark structure and our topology-change strategy represent the "hadron-quark duality" formulated in terms of the Cheshire-Cat mechanism~\cite{CC} for the smooth cross-over between hadrons and quarks. Confrontation with currently available experimental observations is discussed to support this notion.

    ↳ nucl-thastro-ph.SRhep-ph14 citations
24. 24*

    Passive low-energy nuclear recoil detection with color centers

    Bernadette K. Cogswell🇺🇸 · Apurva Goel🇺🇸 · Patrick Huber🇺🇸

    Crystal damage events such as tracks and point defects have been used to record and detect radiation for a long time and recently they have been proposed as a means for dark matter detection. Color centers can be read out optically and we propose a scheme based on selective plane illumination microscopy for sub-micron imaging of large volumes corresponding to kilogram mass detectors. This class of detectors would be passive and would operate at room temperature. We apply these concepts to the detection of reactor neutrinos using coherent elastic neutrino nucleus scattering (CEvNS). Crystal damage formation energies are intrinsically on the order of 25eV, resulting in similarly low nuclear recoil thresholds. This would enable the first observation of reactor neutrino CEvNS with detectors as small as 10g. Additionally, a competitive search for spin-dependent dark matter scattering down to a dark matter mass of 0.3GeV could be possible. Passive crystal detectors might also be attractive for nuclear non-proliferation safeguards if used to monitor reactor power and to put limits on plutonium production. The passive nature and small footprint of the proposed detectors implies that these might fit well within accepted reactor safeguards operations.

    ↳ physics.ins-dethep-exhep-phnucl-exPhys.Rev.Applied(2021)·21 citations
25. 25*

    Searching For Gravitational Waves From Cosmological Phase Transitions With The NANOGrav 12.5-year dataset

    Zaven Arzoumanian🇺🇸 · Paul T. Baker🇺🇸 · Harsha Blumer🇺🇸 · Bence Bécsy🇺🇸 · Adam Brazier🇺🇸 · Paul R. Brook🇺🇸 · Sarah Burke-Spolaor🇺🇸 · Maria Charisi🇺🇸 · Shami Chatterjee🇺🇸 · Siyuan Chen🇫🇷 · James M. Cordes🇺🇸 · Neil J. Cornish🇺🇸 and 53 other authors

    We search for a first-order phase transition gravitational wave signal in 45 pulsars from the NANOGrav 12.5 year dataset. We find that the data can be modeled in terms of a strong first order phase transition taking place at temperatures below the electroweak scale. However, we do not observe any strong preference for a phase-transition interpretation of the signal over the standard astrophysical interpretation in terms of supermassive black holes mergers; but we expect to gain additional discriminating power with future datasets, improving the signal to noise ratio and extending the sensitivity window to lower frequencies. An interesting open question is how well gravitational wave observatories could separate such signals.

    ↳ astro-ph.COhep-phPRL(2021)·161 citations
26. 26*

    Circuit Complexity as a novel probe of Quantum Entanglement: A study with Black Hole Gas in arbitrary dimensions

    Kiran Adhikari🇩🇪 · Sayantan Choudhury🇮🇳 · Satyaki Chowdhury🇮🇳 · K. Shirish🇮🇳 · Abinash Swain🇮🇳

    In this article, we investigate the quantum circuit complexity and entanglement entropy in the recently studied black hole gas framework using the two-mode squeezed states formalism written in arbitrary dimensional spatially flat cosmological Friedmann-Lema$\hat{i}$tre-Robertson-Walker (FLRW) background space-time. We compute the various complexity measures and study the evolution of these complexities by following two different prescriptions viz. Covariant matrix method and Nielsen's method. Independently, using the two-mode squeezed states formalism we also compute the Rényi and Von-Neumann entanglement entropy, which show an inherent connection between the entanglement entropy and quantum circuit complexity. We study the behaviour of the complexity measures and entanglement entropy separately for three different spatial dimensions and observe various significant different features in three spatial dimensions on the evolution of these quantities with respect to the scale factor. Furthermore, we also study the underlying behaviour of the equilibrium temperature with two of the most essential quantities i.e. rate of change of complexity with scale factor and the entanglement entropy. We observe that irrespective of the spatial dimension, the equilibrium temperature depends quartically on entanglement entropy.

    ↳ hep-thcond-mat.stat-mechgr-qchep-ph+1PRD(2021)·28 citations

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