Fri·Apr 7, 2023Friday·April 7, 2023

1. 01*

   Precise probing and discrimination of third-generation scalar leptoquarks

   Anupam Ghosh🇮🇳 · Partha Konar🇮🇳 · Debashis Saha🇮🇳 · Satyajit Seth🇮🇳

   We explore the pair production of third-generation scalar leptoquark at the Large Hadron Collider to next-to-leading order accuracy in QCD, matched to parton shower for a precise probing of the stemming model. We propose to tag two boosted top-like fatjets produced from the decay of heavy leptoquarks in association with notably large missing transverse momentum and consider them as the potential signal. Such a signal demonstrates the capability of a robust discovery prospect in the multivariate analysis with different high-level observables, including jet substructure variables. Various scalar leptoquark models predict different chirality of the top quark appearing from the decay of the leptoquark carrying same electromagnetic charge. We make use of the polarization variables sensitive to the top quark polarization in order to identify the underlying theory.

   hep-phPRD(2023)·12 citations
2. 02*

   Freeze-in Dark Matter via Lepton Portal: Hubble Tension and Stellar Cooling

   Zixuan Xu🇨🇳 · Shuai Xu🇨🇳 · Ruopeng Zhang🇨🇳 · Sibo Zheng🇨🇳

   We propose a new freeze-in dark matter candidate which feebly couples to the standard model charged leptons. The feeble interactions allow it (i) to freeze-in from the Standard Model thermal bath with its relic density being either a fraction or the entirety of the observed dark matter density and (ii) to radiatively decay to two photons in the dark matter mass ranges of order keV scale with lifetime larger than the age of Universe. These features make this model a realistic realization of dark matter with late-time decay to reduce Hubble tension. We show the best-fit value of H_{0}=68.31(69.34) km s^{-1}Mpc^{-1} in light of Planck 2018+BAO(+LSS)+Pantheon data sets. We then use stellar cooling data to place constraints on the parameter space favored by the Hubble tension. While the universal coupling scenario is excluded, the hierarchical coupling scenario can be tested by future observations of white dwarfs after a careful look into photon inverse decay, Primakoff and Bremsstrahlung emission of the dark matter in various stellar systems. The viable parameter space may be linked to anomalies in future X-ray telescopes.

   hep-phastro-ph.COJHEP(2023)·2 citations
3. 03*

   Possible molecular dibaryons with $csssqq$ quarks and their baryon-antibaryon partners

   Shu-Yi Kong🇨🇳 · Jun-Tao Zhu🇨🇳 · Jun He🇨🇳

   In this work, we systematically investigate the charmed-strange dibaryon systems with $csssqq$ quarks and their baryon-antibaryon partners from the interactions ${\Xi }_c^{{(}^{\prime },\ast )}{\Xi }^{(\ast )}$, ${\Omega }_c^{(\ast )}\Lambda$, ${\Omega }_c^{(\ast )}{\Sigma }^{(\ast )}$, ${\Lambda }_c\Omega$ and ${\Sigma }_c^{(\ast )}\Omega$ and their baryon-antibaryon partners from interactions ${\Xi }_c^{{(}^{\prime },\ast )}{\bar{\Xi }}^{(\ast )}$, ${\Omega }_c^{(\ast )}\bar{\Lambda }$, ${\Omega }_c^{(\ast )}{\bar{\Sigma }}^{(\ast )}$, ${\Lambda }_c\bar{\Omega }$ and ${\Sigma }_c^{(\ast )}\bar{\Omega }$. The potential kernels are constructed with the help of effective Lagrangians under SU(3), heavy quark, and chiral symmetries to describe these interactions. To search for possible molecular states, the kernels are inserted into the quasipotential Bethe-Salpeter equation, which is solved to find poles from scattering amplitude. The results suggest that 36 and 24 bound states can be found in the baryon-baryon and baryon-antibaryon interactions, respectively. However, much large values of parameter $\alpha$ are required to produce the bound states from the baryon-antibaryon interactions, which questions the existence of these bound states. Possible coupled-channel effect are considered in the current work to estimate the couplings of the molecular states to the channels considered.

   hep-phnucl-thEPJC(2023)·7 citations
4. 04*

   How baryons appear in low-energy QCD: Domain-wall Skyrmion phase in strong magnetic fields

   Minoru Eto🇯🇵 · Kentaro Nishimura🇯🇵 · Muneto Nitta🇯🇵

   Low-energy dynamics of QCD can be described by pion degrees of freedom in terms of the chiral perturbation theory(ChPT). A chiral soliton lattice(CSL), an array of solitons, is the ground state due to the chiral anomaly in the presence of a magnetic field larger than a certain critical value at finite density. Here, we show in a model-independent and fully analytic manner (at the leading order of ChPT) that the CSL phase transits to a {\it domain-wall Skyrmion phase} when the chemical potential is larger than the critical value ${\mu }_{\mathrm{c}}=16\pi f_{\pi }^2/3m_{\pi }\sim 1.03\mathrm{GeV}$ with the pion's decay constant $f_{\pi }$ and mass $m_{\pi }$, which can be regarded as the nuclear saturation density. There spontaneously appear stable two-dimensional Skyrmions or lumps on a soliton surface, which can be viewed as three-dimensional Skyrmions carrying even baryon numbers from the bulk despite no Skyrme term. They behave as superconducting rings with persistent currents due to a charged pion condensation, and areas of the rings' interiors are quantized. This phase is in scope of future heavy-ion collider experiments.

   hep-phcond-mat.supr-conhep-thnucl-th22 citations
5. 05*

   B meson production in Pb+Pb at 5.02 ATeV at LHC: estimating the diffusion coefficient in the infinite mass limit

   Maria Lucia Sambataro (1 and 2)🇮🇹 · Vincenzo Minissale (2)🇮🇹 · Salvatore Plumari (1 and 2)🇮🇹 · Vincenzo Greco (1 and 2) ((1) Department of Physics and Astronomy 'E. Majorana', University of Catania, Via S. Sofia 64, 1-95123 Catania, Italy, (2) Laboratori Nazionali del Sud, INFN-LNS, Via S. Sofia 62, I-95123 Catania, Italy)🇮🇹

   In the last decade a Quasi-Particle Model (QPM) has been developed to study charm quark dynamics in ultra-relativistic heavy-ion collisions supplying a satisfactory description of the main observables for $D$ meson and providing an estimate of the space-diffusion coefficient $D_s(T)$ from the phenomenology. In this paper, we extend the approach to bottom quarks describing their propagation in the quark-gluon plasma within an event-by-event full Boltzmann transport approach followed by a coalescence plus fragmentation hadronization. We find that QPM approach is able to correctly predict the first available data on $R_{AA}(p_T)$ and $v_2(p_T)$ of single-electron from B decays without any parameter modification w.r.t. the charm. We show also predictions for centralities where data are not yet available for both $v_2(p_T)$ and $v_3(p_T)$. Moreover, we discuss the significant breaking of the expected scaling of the thermalization time ${\tau }_{th}$ with $M_Q/T$, discussing the evolution with mass of $D_s(T)$ to better assess the comparison to lQCD calculations. We find that at $T=T_c$ charm quark $D_s(T)$ is about a factor of 2 larger than the asymptotic value for $M\to \infty$, while bottom $D_s(T)$ is only a $20-25\%$ higher. This implies a $D_s(T)$ which is consistent within the current uncertainty to the most recent lattice QCD calculations with dynamical quarks for $M\to \infty$.

   hep-phnucl-thPLB(2024)·35 citations
6. 06*

   Light-Cone Sum Rules for $S$-wave $B\to K\pi$ Form Factors

   Sébastien Descotes-Genon🇫🇷 · Alexander Khodjamirian🇩🇪 · Javier Virto🇪🇸 · K. Keri Vos🇳🇱

   We derive a set of light-cone sum rules relating the $S$-wave $B\to K\pi$ hadronic form factors to the $B$-meson light-cone distribution amplitudes (LCDAs), taking into account the complete set of LCDAs up to and including twist four. These results complement the sum rules for the $P$-wave $B\to K\pi$ form factors obtained earlier. We then use the new sum rules to estimate the $S$-wave contributions to $B\to K\pi \ell \ell$ decays as a function of the $K\pi$ invariant mass. We pay particular attention to the fact that the $S$-wave $K\pi$ spectrum cannot be modelled by a sum of Breit-Wigner resonances, and employ a more consistent dispersive coupled-channel approach. We compare our predictions for branching ratios and angular observables with LHCb measurements in two different kinematic regions, around $K^{\ast }(892)$ and $K_0^{\ast }(1430)$. We observe an overall compatibility and discuss possible improvements of our model to obtain a better description of the $B\to K\pi$ form factors over a large kinematic range.

   hep-phhep-latJHEP(2023)·16 citations
7. 07*

   Azimuthal fluctuations and number of muons at the ground in muon-depleted proton air showers at PeV energies

   A. Bakalová🇨🇿 · R. Conceição🇵🇹 · L. Gibilisco🇵🇹 · V. Novotný🇨🇿 · M. Pimenta🇵🇹 · B. Tomé🇵🇹 · J. Vícha🇨🇿

   Muon counting is an effective strategy for discriminating between gamma and hadron-initiated air showers. However, their detection, which requires shielded detectors, is highly expensive and challenging to implement across large, environmentally sensitive areas. This work allowed to establish for the first time that at PeV energies the gamma/hadron discriminator based on the new $LCm$ variable have proton rejection levels of the order of $10^{-4}$, outperforming the discrimination power based on the counting of the number of muons. A thorough examination of muon depleted showers at the PeV energies and the simulation strategy devised to achieve the required $\mathcal{O}(10^6)$ simulated showers is presented.

   hep-phastro-ph.HEhep-exPRD(2025)·7 citations
8. 08*

   Right-Handed Neutrino Dark Matter with Forbidden Annihilation

   Yu Cheng🇨🇳 · Shao-Feng Ge🇨🇳 · Jie Sheng🇨🇳 · Tsutomu T. Yanagida🇨🇳

   The seesaw mechanism with three right-handed neutrinos has one as a well-motivated dark matter candidate if stable and the other two can explain baryon asymmetry via the thermal leptogenesis scenario. We explore the possibility of introducing additional particles to make the right-handed neutrino dark matter in thermal equilibrium and freeze out through a forbidden annihilation channel. Nowadays in the Universe, this forbidden channel can be reactivated by a strong gravitational potential such as the supermassive black hole in our galaxy center. The Fermi-LAT gamma ray data and dark matter relic density require this right-handed neutrino dark matter to have mass below $100$GeV and the existence of an additional boson $\varphi$ that can be tested at future lepton colliders.

   hep-phastro-ph.GAastro-ph.HEhep-exPRD(2023)·13 citations
9. 09*

   Lepton universality violation in the MF331 model

   P. N. Thu🇻🇳 · N. T. Duy🇻🇳 · A. E. Carcamo Hernandez🇨🇱 · D. T. Huong🇻🇳

   We perform a detailed study of the $\text{b}\to \text{c}\tau \nu$ and $\text{b}\to \text{s}{l}^{+}{l}^{-}$ processes in a minimal flipped 331 model based on the $SU(3{)}_C\times SU(3{)}_L\times U(1{)}_N$ gauge symmetry. The non universal $SU(3{)}_L\times U(1{)}_N$ symmetry in the lepton sector gives rise to non universal neutral and charged currents involving heavy non SM gauge bosons and SM leptons that yield radiative contributions to the $b\to s$, $b\to c$, $s\to u$ and $d\to u$ transitions arising from one loop level penguin and box diagrams. We found that the observables related to these transitions agree with their experimental values in a region of parameter space that includes TeV scale exotic up type quarks, within the LHC's reach.

   hep-phPTEP(2023)·7 citations
10. 10*

    Femtoscopic signatures of the lightest S-wave scalar open-charm mesons

    Miguel Albaladejo🇪🇸 · Juan Nieves🇪🇸 · Enrique Ruiz-Arriola🇪🇸

    We predict femtoscopy correlation functions for $S$--wave $D_{(s)}\varphi$ pairs of lightest pseudoscalar open charm mesons and Goldstone bosons from next-to-leading order unitarized heavy-meson chiral perturbation theory amplitudes. The effect of the two-state structure around $2300\text{MeV}$ can be clearly seen in the $(S,I)=(0,1/2)$ $D\pi$, $D\eta$, $D_s\overline{K}$ correlation functions, while in the scalar-strange $(1,0)$ sector, the $D_{s0}^{\ast }(2317{)}^{\pm }$ state lying below the $DK$ threshold produces a depletion of the correlation function near threshold. These exotic states owe their existence to the nonperturbative dynamics of Goldstone-boson scattering off $D_{(s)}$. The predicted correlation functions could be experimentally measured and will shed light into the hadron spectrum confirming that it should be viewed as more than a collection of quark model states.

    hep-phPRD(2023)·52 citations
11. 11*

    Probing Dark QCD Sector through the Higgs Portal with Machine Learning at the LHC

    Chih-Ting Lu🇨🇳 · Huifang Lv🇨🇳 · Wei Shen🇨🇳 · Lei Wu🇨🇳 · Jia Zhang🇨🇳

    The QCD-like dark sector with GeV-scale dark hadrons has the potential to generate new signatures at the Large Hadron Collider (LHC). In this paper, we consider a singlet scalar mediator in the tens of GeV-scale that connects the dark sector and the Standard Model (SM) sector via the Higgs portal. We focus on the Higgs-strahlung process, $q{\overline{q}}^{\prime }\to W^{\ast }\to WH$, to produce a highly boosted Higgs boson. Our scenario predicts two different processes that can generate dark mesons: (1) the cascade decay from the Higgs boson to two light scalar mediators and then to four dark mesons; (2) the Higgs boson decaying to two dark quarks, which then undergo a QCD-like shower and hadronization to produce dark mesons. We apply machine learning techniques, such as Convolutional Neural Network (CNN) and Energy Flow Network (EFN), to the fat jet structure to distinguish these signal processes from large SM backgrounds. We find that the branching ratio of the Higgs boson to two light scalar mediators can be constrained to be less than $10\%$ at 14 TeV LHC with $\mathcal{L}=3000f{b}^{-1}$.

    hep-phJHEP(2023)·11 citations
12. 12*

    Exploring fully heavy scalar tetraquarks $QQ\overline{Q}\overline{Q}$

    S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · B. Barsbay🇹🇷 · H. Sundu🇹🇷

    The masses, current couplings and widths of the fully heavy scalar tetraquarks $X_{4Q}=QQ\overline{Q}\overline{Q}$, $Q=c,b$ are calculated by modeling them as four-quark systems composed of axial-vector diquark and antidiquark. The masses $m^{(\prime )}$ and couplings $f^{(\prime )}$ of these tetraquarks are computed in the context of the QCD sum rule method by taking into account a nonperturbative term proportional to the gluon condensate $⟨{\alpha }_s{G}^2/\pi ⟩$. Results $m=(6570\pm 55)\mathrm{MeV}$ and $m^{\prime }=(18540\pm 50)\mathrm{MeV}$ are used to fix kinematically allowed hidden-flavor decay channels of these states. It turns out that, the processes $X_{4c}\to J/\psi J/\psi$, $X_{4c}\to {\eta }_c{\eta }_c$, and $X_{4c}\to {\eta }_c{\chi }_{c1}(1P)$ are possible decay modes of $X_{4c}$. The partial widths of these channels are evaluated by means of the couplings $g_i,i=1,2,3$ which describe strong interactions of tetraquark $X_{4c}$ and mesons at relevant vertices. The couplings $g_i$ are extracted from the QCD three-point sum rules by extrapolating corresponding form factors $g_i(Q^2)$ to the mass-shell of a final meson. The mass of the scalar tetraquark $X_{4b}$ is below the ${\eta }_b{\eta }_b$ and ${\rm Y}(1S){\rm Y}(1S)$ thresholds, therefore it does not fall apart to these bottomonia, but transforms to conventional particles through other mechanisms. Comparing $m=(6570\pm 55)\mathrm{MeV}$ and ${\Gamma }_{4c}=(110\pm 21)\mathrm{MeV}$ with parameters of structures observed by the LHCb, ATLAS and CMS collaborations, we interpret $X_{4c}$ as the resonance $X(6600)$ reported by CMS. Comparisons are made with other theoretical predictions.

    hep-phhep-exhep-latPLB(2023)·47 citations
13. 13*

    Chromoelectric field correlator for quarkonium transport in the strongly coupled $\mathcal{N}=4$ Yang-Mills plasma from AdS/CFT

    Govert Nijs🇺🇸 · Bruno Scheihing-Hitschfeld🇺🇸 · Xiaojun Yao🇺🇸

    Previous studies have shown that a gauge-invariant correlation function of two chromoelectric fields connected by a straight timelike adjoint Wilson line encodes crucial information about quark-gluon plasma (QGP) that determines the dynamics of small-sized quarkonium in the medium. Motivated by the successes of holographic calculations to describe strongly coupled QGP, we calculate the analog gauge-invariant correlation function in strongly coupled $\mathcal{N}=4$ supersymmetric Yang-Mills theory at finite temperature by using the AdS/CFT correspondence. Our results indicate that the transition processes between bound and unbound quarkonium states are suppressed in strongly coupled plasmas, and moreover, the leading contributions to these transition processes vanish in both the quantum Brownian motion and quantum optical limits of open quantum system approaches to quarkonia.

    hep-phhep-thnucl-thJHEP(2023)·19 citations
14. 14*

    TMD Handbook

    Renaud Boussarie🇫🇷 · Matthias Burkardt🇺🇸 · Martha Constantinou🇺🇸 · William Detmold🇺🇸 · Markus Ebert🇩🇪 · Michael Engelhardt🇺🇸 · Sean Fleming🇺🇸 · Leonard Gamberg🇺🇸 · Xiangdong Ji🇺🇸 · Zhong-Bo Kang🇺🇸 · Christopher Lee🇺🇸 · Keh-Fei Liu🇺🇸 and 17 other authors

    This handbook provides a comprehensive review of transverse-momentum-dependent parton distribution functions and fragmentation functions, commonly referred to as transverse momentum distributions (TMDs). TMDs describe the distribution of partons inside the proton and other hadrons with respect to both their longitudinal and transverse momenta. They provide unique insight into the internal momentum and spin structure of hadrons, and are a key ingredient in the description of many collider physics cross sections. Understanding TMDs requires a combination of theoretical techniques from quantum field theory, nonperturbative calculations using lattice QCD, and phenomenological analysis of experimental data. The handbook covers a wide range of topics, from theoretical foundations to experimental analyses, as well as recent developments and future directions. It is intended to provide an essential reference for researchers and graduate students interested in understanding the structure of hadrons and the dynamics of partons in high energy collisions.

    hep-phhep-latnucl-th264 citations
15. 15*

    Back-to-back inclusive dijets in DIS at small $x$: Gluon Weizsäcker-Williams distribution at NLO

    Paul Caucal🇫🇷 · Farid Salazar🇺🇸 · Björn Schenke🇺🇸 · Tomasz Stebel🇵🇱 · Raju Venugopalan🇺🇸

    In JHEP 11 (2022) 169, we performed the first complete computation of the back-to-back inclusive di-jet cross-section in Deeply Inelastic Scattering (DIS) at small $x_{\mathrm{Bj}}$ to next-to-leading order (NLO) in the Color Glass Condensate effective field theory (CGC EFT). We demonstrate here that for di-jets with relative transverse momentum $P_{\perp }$ and transverse momentum imbalance $q_{\perp }$, to leading power in $q_{\perp }/P_{\perp }$, the cross-section for longitudinally polarized photons can be fully factorized into the product of a perturbative impact factor and the nonperturbative Weizsäcker-Williams (WW) transverse momentum dependent (TMD) gluon distribution to NLO accuracy. The impact factor can further be expressed as the product of a universal soft factor which resums Sudakov double and single logs in $P_{\perp }/q_{\perp }$ and a coefficient function given by a remarkably compact analytic expression. We show that in the CGC EFT the WW TMD satisfies a kinematically constrained JIMWLK renormalization group evolution in rapidity. This factorization formula is valid to all orders in $Q_s/q_{\perp }$ for $q_{\perp },Q_s\ll P_{\perp }$, where $Q_s$ is the semi-hard saturation scale that grows with rapidity.

    hep-phnucl-thJHEP(2023)·69 citations
16. 16*

    Impact of dimension-eight SMEFT operators in the EWPO and Triple Gauge Couplings analysis in Universal SMEFT

    Tyler Corbett🇦🇹 · Jay Desai🇺🇸 · O. J. P. Eboli🇧🇷 · M. C. Gonzalez-Garcia🇺🇸 · Matheus Martines🇧🇷 · Peter Reimitz🇧🇷

    We perform a complete study of the electroweak precision observables and electroweak gauge boson pair production in terms of the SMEFT up to $\mathcal{O}(1/{\Lambda }^4)$ under the assumption of universal, C and P conserving new physics. We show that the analysis of data from those two sectors allows us to obtain closed constraints in the relevant parameter space in this scenario. In particular we find that the Large Hadron Collider data can independently constrain the Wilson coefficients of the dimension-six and -eight operators directly contributing to the triple gauge boson vertices. Our results show that the impact of dimension-eight operators in the study of triple gauge couplings is small.

    hep-phPRD(2023)·41 citations
17. 17*

    Anisotropic Distance Ladder in Pantheon+ Supernovae

    Ruairí McConville · Eoin Ó Colgáin🇮🇪

    We decompose Pantheon+ Type Ia supernovae (SN) in hemispheres on the sky finding angular variations up to $4$ km/s/Mpc in the Hubble constant $H_0$ both in the SH0ES redshift range $0.0233<z<0.15$ and in extended redshift ranges. The variations are driven largely by variations in absolute magnitude from SN in Cepheid hosts, but are reinforced by SN in the Hubble flow. $H_0$ is larger in a hemisphere encompassing the CMB dipole direction. The variations we see exceed the errors on the recent SH0ES determination, $H_0=73.04\pm 1.04$ km/s/Mpc, but are not large enough to explain early versus late Universe discrepancies in the Hubble constant. Nevertheless, the Cepheid-SN distance ladder is anisotropic at current precision. The anisotropy may be due to a breakdown in the Cosmological Principle, or mundanely due to a statistical fluctuation in a small sample of SN in Cepheid host galaxies.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2023)·64 citations
18. 18*

    Electric-charge-dependent directed flow splitting of produced quarks in Au+Au collisions

    STAR Collaboration

    We report directed flow ($v_1$) of multistrange baryons ($\Xi$ and $\Omega$) and improved $v_1$ data for $K^{-}$, $\bar{p}$, $\bar{\Lambda }$ and $\varphi$ in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=$27 and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). We focus on particles whose constituent quarks are not transported from the incoming nuclei but instead are produced in the collisions. At intermediate impact parameters, we examine quark coalescence behavior for particle combinations with identical quark content, and search for any departure from this behavior (``splitting'') for combinations having non-identical quark content. Under the assumption of quark coalescence for produced quarks, the splitting strength appears to increase with the electric charge difference of the constituent quarks in the combinations, consistent with electromagnetic effect expectations.

    ↳ nucl-exhep-phnucl-thPLB(2025)·12 citations
19. 19*

    Minihalos as probes of the inflationary spectrum: accurate boost factor calculation and new CMB constraints

    Guillermo Franco Abellán🇳🇱 · Gaétan Facchinetti🇧🇪

    Although the spectrum of primordial fluctuations has been accurately measured on scales above $\sim 0.1\mathrm{Mpc}$, only upper limits exist on smaller scales. In this study, we investigate generic monochromatic enhancements to the $\Lambda$CDM spectrum that trigger the collapse of ultracompact minihalos (UCMHs) well before standard structure formation. We refine previous treatments by considering a mixed population of halos with different density profiles, that should realistically arise as a consequence of late-time accretion and mergers. Assuming that dark matter (DM) can self-annihilate, we find, as expected, that UCMHs can greatly enhance the annihilation rate around recombination, significantly imprinting the cosmic microwave background (CMB) anisotropies. However, we provide additional insight on the theoretical uncertainties that currently impact that boost and which may affect late-time probes such as the 21 cm line or $\gamma$-ray signals. We derive constraints on the primordial power spectrum on small scales using the ExoCLASS/HYREC codes and the Planck legacy data. We account for the velocity dependence of the DM annihilation cross-section ($s$- or $p$-wave), annihilation channel, the DM particle mass and the inclusion of late-time halo mergers. Our $s$-wave constraints are competitive with previous literature, excluding primordial amplitudes $A_{\star }\gtrsim 10^{-6.5}$ at wavenumbers $k\sim 10^4-10^7{\mathrm{Mpc}}^{-1}$. For the first time, we highlight that even $p$-wave processes have constraining power on the primordial spectrum for cross-sections still allowed by currently the strongest astrophysical constraints. Finally, we provide an up-to-date compilation of the most stringent limits on the primordial power spectrum across a wide range of scales.

    ↳ astro-ph.COgr-qchep-phJCAP(2023)·12 citations
20. 20*

    $B\to D^{\ast }$ vector, axial-vector and tensor form factors for the full $q^2$ range from lattice QCD

    Judd Harrison🇬🇧 · Christine T. H. Davies🇬🇧

    We compute the complete set of SM and tensor $B_{(s)}\to D_{(s)}^{\ast }\ell \bar{\nu }$ semileptonic form factors across the full kinematic range of the decay using second generation MILC $n_f=2+1+1$ HISQ gluon field configurations and HISQ valence quarks, with the heavy-HISQ method. Lattice spacings range from $0.09\mathrm{fm}$ to $0.044\mathrm{fm}$ with pion masses from $\approx 300\mathrm{MeV}$ down to the physical value and heavy quark masses ranging between $\approx 1.5m_c$ and $4.1m_c\approx 0.9m_b$; currents are normalised nonperturbatively. Using the recent $B_{(s)}\to D_{(s)}^{\ast }\ell {\bar{\nu }}_{\ell }$ data from Belle and LHCb together with our form factors we determine a model independent value of $V_{cb}=39.03(56{)}_{\exp }(67{)}_{\mathrm{latt}}\times 10^{-3}$, in agreement with previous exclusive determinations and in tension with the inclusive result at the level of $3.6\sigma$. We observe a $\approx 1\sigma$ tension between the shape of the differential decay rates computed using our form factors and those measured by Belle. We compute a lattice-only SM value for the ratio of semitauonic and semimuonic decay rates, $R(D^{\ast })=0.273(15)$, which we find to be closer to the recent Belle measurement and HFLAV average than theory predictions using fits to experimental differential rate data for $B\to D^{\ast }\ell {\bar{\nu }}_{\ell }$. Determining $V_{cb}$ using the total rate for $B\to D^{\ast }\ell \nu$ gives a value in agreement with inclusive results. We compute the longitudinal polarisation fraction for the semitauonic mode, $F_L^{D^{\ast }}=0.395(24)$, which is in tension at the level of $2.2\sigma$ with the recent Belle measurement. Our calculation combines $B\to D^{\ast }$ and $B_s\to D_s^{\ast }$ lattice results, and we provide an update which supersedes our previous lattice computation of the $B_s\to D_s^{\ast }$ form factors. We also give the chiral perturbation theory needed to analyse the tensor form factors.

    ↳ hep-lathep-phPRD(2024)·112 citations
21. 21*

    Searching for Primordial Black Holes with the Einstein Telescope: impact of design and systematics

    G. Franciolini🇮🇹 · F. Iacovelli🇨🇭 · M. Mancarella🇮🇹 · M. Maggiore🇨🇭 · P. Pani🇮🇹 · A. Riotto🇨🇭

    Primordial Black Holes (PBHs) have recently attracted much attention as they may explain some of the LIGO/Virgo/KAGRA observations and significantly contribute to the dark matter in our universe. The next generation of Gravitational Wave (GW) detectors will have the unique opportunity to set stringent bounds on this putative population of objects. Focusing on the Einstein Telescope (ET), in this paper we analyse in detail the impact of systematics and different detector designs on our future capability of observing key quantities that would allow us to discover and/or constrain a population of PBH mergers. We also perform a population analysis, with a mass and redshift distribution compatible with the current observational bounds. Our results indicate that ET alone can reach an exquisite level of accuracy on the key observables considered, as well as detect up to tens of thousands of PBH binaries per year, but for some key signatures (in particular high--redshift sources) the cryogenic instrument optimised for low frequencies turns out to be crucial, both for the number of observations and the error on the parameters reconstruction. As far as the detector geometry is concerned, we find that a network consisting of two separated L--shaped interferometers of 15 (20)~km arm length, oriented at $45^{\circ }$ with respect to each other performs better than a single triangular shaped instrument of 10 (15)~km arm length, for all the metrics considered.

    ↳ gr-qcastro-ph.COhep-phPRD(2023)·46 citations
22. 22*

    Mitigating Green's function Monte Carlo signal-to-noise problems using contour deformations

    Gurtej Kanwar🇨🇭 · Alessandro Lovato🇺🇸 · Noemi Rocco🇺🇸 · Michael Wagman🇺🇸

    The Green's function Monte Carlo (GFMC) method provides accurate solutions to the nuclear many-body problem and predicts properties of light nuclei starting from realistic two- and three-body interactions. Controlling the GFMC fermion-sign problem is crucial, as the signal-to-noise ratio decreases exponentially with Euclidean time, requiring significant computing resources. Inspired by similar scenarios in lattice quantum field theory and spin systems, in this work, we employ integration contour deformations to improve the GFMC signal-to-noise ratio. Machine learning techniques are used to select optimal contours with minimal variance from parameterized families of deformations. As a proof of principle, we consider the deuteron binding energies and Euclidean density response functions. We only observe mild signal-to-noise improvement for the binding energy case. On the other hand, we achieve an order of magnitude reduction of the variance for Euclidean density response functions, paving the way for computing electron- and neutrino-nucleus cross-sections of larger nuclei.

    ↳ nucl-thhep-lathep-phPRC(2024)·8 citations
23. 23*

    Glasma properties in small proper time expansion

    Margaret E. Carrington🇨🇦 · Wade N. Cowie🇨🇦 · Bryce T. Friesen🇨🇦 · Stanislaw Mrowczynski🇵🇱 · Doug Pickering🇨🇦

    In a series of works by two of us, various characteristics of the glasma from the earliest phase of relativistic heavy-ion collisions have been studied using a proper time expansion. These characteristics include: energy density, longitudinal and transverse pressures, collective flow, angular momentum and parameters of jet quenching. In this paper we extend the proper time interval where our results are reliable by working at higher order in the expansion. We also generalize our previous study of jet quenching by extending our calculations to consider inhomogeneous glasma. Inhomogeneities are an important aspect of physically realistic systems that are difficult to include in calculations and are frequently ignored.

    ↳ nucl-thhep-phPRC(2023)·9 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.