Thu·May 26, 2022Thursday·May 26, 2022

1. 01*

   A triplet gauge boson with hypercharge one

   Renato M. Fonseca🇪🇸

   A vector boson $W_1^{\mu }$ with the quantum numbers $\left(3,1\right)$ under $SU{\left(2\right)}_L\times U(1{)}_Y$ could in principle couple with the Higgs field via the renormalizable term $W_1^{\mu \ast }H{D}_{\mu }H$. This interaction is known to affect the $T$ parameter and, in so doing, it could potentially explain the recent CDF measurement of the W-boson mass. As it is often the case with vectors, building a viable model with a $W_1$ gauge boson is non-trivial. In this work I will describe two variations of a minimal setup containing this field; they are based on an extended $SO(5)\times SU\left(2\right)\times U(1)$ electroweak group. I will nevertheless show that interactions such as $W_1^{\mu \ast }H{\partial }_{\mu }H$ are never generated in a Yang-Mills theory. A coupling between $W_1$, $H$ and another Higgs doublet $H^{\prime }$ is possible though. Finally, I will provide an explicit recipe for the construction of viable models with gauge bosons in arbitrary representations of the Standard Model group; depending on the quantum numbers, they may couple to pairs of Standard Model fermions, or to a Standard Model fermion and an exotic one.

   hep-phPRD(2023)·5 citations
2. 02*

   Constraints on energy scales from dark matter decay in a gauged $B-L$ model

   Guillermo Gambini🇧🇷 · Pedro C. de Holanda🇧🇷 · Saulo Carneiro🇧🇷

   Popular extensions of the standard model of particle physics feature new fields and symmetries which could, for example, dynamically generate neutrino masses from $B-L$ spontaneous symmetry breaking. If a new light scalar that decays into dark radiation appears in the spectrum of the theory, it could significantly modify the cosmological observables. In this case, cold dark matter could have a stable and a decaying component and limits on its decay rate ${\Gamma }_{\mathrm{dcdm}}$ can be used to put constraints on the new energy scales of a given model. We illustrate this idea using a gauged $B-L$ model where the dark radiation is in the form of light neutrinos.

   hep-phBraz.J.Phys.(2026)·2 citations
3. 03*

   One-loop matching for gluon lattice TMDs

   Stella T. Schindler🇺🇸 · Iain W. Stewart🇺🇸 · Yong Zhao🇺🇸

   Transverse-momentum-dependent parton distributions (TMDs) can be calculated from first principles by computing a related set of Euclidean lattice observables and connecting them via a factorization formula. This work focuses on the leading-power factorization formula connecting the lattice quasi-TMD and continuum Collins TMD for gluons. We calculate the one-loop gluon matching coefficient, which is known to be independent of spin and exhibits no mixing with quarks. We demonstrate that this coefficient satisfies Casimir scaling with respect to the quark matching coefficient at one-loop order. Our result facilitates reliable lattice QCD calculations of gluon TMDs.

   hep-phhep-latnucl-thJHEP(2022)·24 citations
4. 04*

   Designing Observables for Quantum Interference in Jets at Subleading Color

   Andrew J. Larkoski🇺🇸

   The large-$N_c$ or topologically planar limit of gauge theories can be considered as a classical limit because all gauge bosons are distinguishable particles and therefore cannot exhibit interference. Quantum effects due to the flow of color therefore arise starting at subleading in $1/N_c$. We introduce kinematic observables explicitly sensitive to effects at subleading color formed from the ratio of interfering to squared color-ordered amplitudes. Such observables are in general not infrared and collinear safe, so we introduce angular observables defined from appropriate multi-point energy correlators motivated by the form of color-ordered amplitudes. We demonstrate that color interference effects are manifest as sinusoidal oscillation in the simplest system, a collinear jet with three particles, and show the limitations of predicting this observable in all-purpose, leading-color parton shower Monte Carlos.

   hep-phhep-exnucl-exnucl-thSciPost Phys.(2023)·4 citations
5. 05*

   Looking forward to forward physics at the CERN's LHC

   Luis A. Anchordoqui🇺🇸

   For decades, new physics searches in collider experiments have focused on the high-$p_T$ region. However, it has recently become evident that the LHC physics potential has not been fully exploited. To be specific, forward collisions, which produce particles along the beamline with enormous rates, have been almost completely ignored. For all practical purposes, these collisions are a treasure trove of physics, containing the highest-energy neutrinos ever produced by humans, as well as possible evidence for dark matter, light and weakly-coupled particles, and new forces. In the upcoming LHC Run 3 the ForwArd Search ExpeRiment (FASER) and its cousin FASER$\nu$ will extend the LHC's physics potential. A continuation of this forward physics program for the HL-LHC aims at the Forward Physics Facility (FPF), with larger scale experiments. In this report, I give an overview of the physics motivations for FASER, FASER$\nu$, and the FPF experiments, including both Standard Model and beyond Standard Model physics.

   hep-phSciPost Phys.Proc.(2023)·6 citations
6. 06*

   Quark unitarity triangles

   S. Rebeca Juárez Wysozka🇲🇽 · Piotr Kielanowski🇲🇽 · Liliana Vazquez Mercado🇲🇽

   The angles of all unitarity triangles of the Cabibbo-Kobayashi-Maskawa matrix are determined from the experimental data. Our analysis is independent of the parameterization of the CKM matrix and it is based on the predictions of the unitarity for the angles and the areas of the unitarity triangles. We note that the lengths of the sides of the four unitarity triangles determined from the experimental data do not form a triangle. We resolve this incompatibility by performing a constrained fit, assuming the equality of the area of the unitarity triangles. We demonstrate that the measured data are compatible with the predictions of the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, but there is a $2\sigma$ tension for one of the triangles. We show that the angles of the unitarity triangles obtained by the multiplication of the rows of the CKM matrix can be obtained from the angles obtained by the multiplication of the columns. The equality of those two types of the angles is a simple, but a very powerful test of the general structure of the Standard Model.

   hep-phInt.J.Mod.Phys.A(2022)·0 citations
7. 07*

   New aspect of chiral and axial breaking in QCD

   Chuan-Xin Cui🇨🇳 · Mamiya Kawaguchi🇨🇳 · Jin-Yang Li🇨🇳 · Shinya Matsuzaki🇨🇳 · Akio Tomiya🇯🇵

   Violation of the $U(1)$ axial symmetry in QCD is stricter than the chiral $SU(2)$ breaking, simply because of the presence of the quantum axial anomaly. If the QCD gauge coupling is sent to zero, the strength of the $U(1)$ axial breaking coincides with that of the chiral $SU(2)$ breaking, which we shall in short call an axial-chiral coincidence. This coincidence is trivial since QCD then becomes a non-interacting theory. Actually, there exists another limit in the QCD parameter space, where an axial-chiral coincidence occurs even with nonzero QCD gauge coupling, that can be dubbed a nontrivial coincidence: it is the case with the massive light quarks $(m_l\ne 0)$ and the massless strange quark ($m_s=0$), due to the flavor-singlet nature of the topological susceptibility. This coincidence is robust and tied to the anomalous chiral Ward-Takahashi identity, which is operative even at hot QCD. This implies that the chiral $SU(2)$ symmetry is restored simultaneously with the $U(1)$ axial symmetry at high temperatures. This simultaneous restoration is independent of $m_l(\ne 0)$, hence is irrespective to the order of the chiral phase transition. In this paper, we discuss how the real-life QCD can be evolved from the nontrivial chiral-axial coincidence limit, by working on a Nambu-Jona-Lasinio model with the $U(1)$ axial anomaly contribution properly incorporated. It is shown that at high temperatures the large differences between the restorations of the chiral $SU(2)$ symmetry and the $U(1)$ axial symmetry for two light quarks and a sufficiently large current mass for the strange quark is induced by a significant interference of the topological susceptibility. Thus the deviation from the nontrivial coincidence, which is monitored by the strange quark mass controlling the topological susceptibility, provides a new way of understanding the chiral $SU(2)$ and $U(1)$ axial breaking in QCD.

   hep-phhep-lathep-thnucl-thParticles(2024)·10 citations
8. 08*

   Boosted displaced decay of right-handed neutrinos at CMS, ATLAS and MATHUSLA

   Priyotosh Bandyopadhyay🇮🇳 · Eung Jin Chun🇰🇷 · Chandrima Sen🇮🇳

   We investigate boosted displaced signatures in the Type-I seesaw mechanism associated with the $B-L$ gauge symmetry. Such events arise from decays of right-handed neutrinos depending on their Yukawa couplings and masses. Considering two scenarios: (a) three degenerate right-handed neutrinos whose Yukawa couplings are reconstructed from the observed neutrino masses and mixing; (b) only one right-handed neutrino which decouples from the observed neutrino mass generation and thus its coupling can be arbitrarily small, a detailed PYTHIA based simulation is performed to determine the parameter regions of the $B-L$ gauge boson mass, the neutrino Yukawa couplings, and the right-handed neutrino mass sensitive to CMS, ATLAS, proposed FCC-hh detector and MATHUSLA at the centre of mass energies of 14, 27 and 100 TeV via displaced signatures. We also show in detail how the boost effect enhances the displaced decay lengths, especially for the longitudinal ones, and hinders the probe of Majorana nature of neutrinos.

   hep-phJHEP(2023)·9 citations
9. 09*

   Faddeev fixed-center approximation to the $D\bar{D}K$ system and the hidden charm $K_{c\bar{c}}(4180)$ state

   Xiang Wei🇨🇳 · Qing-Hua Shen🇨🇳 · Ju-Jun Xie🇨🇳

   We perform a theoretical study on the $D\bar{D}K$ three body system, using the fixed center approximation to the Faddeev equations, considering the interaction between $D$ and $K$, $D$ and $\bar{D}$ from the chiral unitary approach. We assume the scattering of $K$ meson on a clusterized system $D\bar{D}$, where a scalar meson $X(3720)$ could be formed. Thanks to the strong $DK$ interaction, where the scalar $D_{s0}^{\ast }(2317)$ meson is dynamically generated, a resonance structure shows up in the modulus squared of the three body $K$-$(D\bar{D}{)}_{X(3720)}$ scattering amplitude and supports that a $D\bar{D}K$ bound state can be formed. The result is in agreement with previous theoretical studies, which claim a new excited hidden charm $K$ meson, $K_{c\bar{c}}(4180)$ with quantum numbers $I(J^P)=\frac{1}{2}(0^{-})$ and mass about $4180$ MeV. It is expected that these theoretical results motivate its search in experimental measurements.

   hep-phhep-exnucl-exnucl-thEPJC(2022)·19 citations
10. 10*

    Exact strangeness conservation in heavy ion collisions

    Krzysztof Redlich🇵🇱 · Natasha Sharma🇮🇳

    We investigate the increase in strangeness production with charged particle multiplicity ($d{N}_{ch}/dy$) seen by the ALICE collaboration at CERN in p-p, p-Pb and Pb-Pb collisions using the hadron resonance gas model. The strangeness canonical ensemble is used taking into account the interactions among hadrons using S-matrix corrections based on known phase shift analyses. We show the essential role of constraints due to the exact conservation of strangeness which is instrumental to describing observed features of strange particle yields and their scaling with $d{N}_{ch}/dy$. Furthermore, the results on comparing the hadron resonance gas model with and without S-matrix corrections, are presented. We observe that the interactions introduced by the phase shift analysis via the S-matrix formalism are essential for a better description of the yields data independent of collision system. This work is based on our long-lasting collaboration and most recent publications with Jean Cleymans.

    hep-phEPJ Web Conf.(2022)·2 citations
11. 11*

    Stability of non-topological string in supersymmetric $SU(2)\times U(1)$ gauge theory

    Yukihiro Kanda🇯🇵 · Nobuhiro Maekawa🇯🇵

    We construct a non-topological string solution for a supersymmetric gauge theory with $SU(2)\times U(1)$ gauge symmetry which is spontaneously broken to $U(1)$ by developing the vacuum expectation value of two doublet Higgses. It is a supersymmetric extension of the electroweak string while supersymmetry is unbroken. We discuss the classical stability of the non-topological string by perturbations. We show that the classical stability are determined only by two parameters, and that the allowed region becomes essentially the same as in the electroweak string.

    hep-phInt.J.Mod.Phys.A(2022)·3 citations
12. 12*

    Flavon Signatures at the HL-LHC

    Marco A. Arroyo-Ureña🇲🇽 · Amit Chakraborty🇮🇳 · J. Lorenzo Díaz-Cruz🇲🇽 · Dilip Kumar Ghosh🇮🇳 · Najimuddin Khan🇮🇳 · Stefano Moretti🇬🇧

    The detection of a single Higgs boson at the Large Hadron Collider (LHC) has allowed one to probe some properties of it, including the Yukawa and gauge couplings. However, in order to probe the Higgs potential, one has to rely on new production mechanisms, such as Higgs pair production. In this paper, we show that such a channel is also sensitive to the production and decay of a so-called `Flavon' field ($H_F$), a new scalar state that arises in models that attempt to explain the hierarchy of the Standard Model (SM) fermion masses. Our analysis also focuses on the other decay channels involving the Flavon particle, specifically the decay of the Flavon to a pair of $Z$ bosons ($H_F\to ZZ$) and the concurrent production of a top quark and charm quark ($H_F\to tc$), having one or more leptons in the final states. In particular, we show that, with 3000 fb${}^{-1}$ of accumulated data at 14 TeV (the Run 3 stage) of the LHC an heavy Flavon $H_F$ with mass $M_{H_F}\simeq 2m_t$ can be explored with $3\sigma -5\sigma$ significance through these channels.

    hep-phPRD(2023)·11 citations
13. 13*

    Production of three isolated photons in the parton Reggeization approach at high energies

    Anton Karpishkov🇷🇺 · Vladimir Saleev🇷🇺

    We study a large-$p_T$ three-photon production in proton-proton collisions at the LHC. We use the leading order (LO) approximation of the parton Reggeization approach consistently merged with the next-to-leading order corrections originated from the emission of additional jet. For numerical calculations we use the parton-level generator KaTie and modified KMR-type unintegrated parton distribution functions which satisfy exact normalization conditions for arbitrary $x$. We compare our prediction with data from ATLAS collaboration at the center-of-mass energy $\sqrt{s}=8$ TeV. We find that the inclusion of the real next-to-leading-order corrections leads to a good agreement between our predictions and data with the same accuracy as for the next-to-next-to-leading calculations based on the collinear parton model of QCD. At higher energies ($\sqrt{s}=13$ and 27 TeV) parton Reggeization approach predicts larger cross sections, up to $\sim 15$ \% and $\sim 30$ \%, respectively.

    hep-phPRD(2022)·3 citations
14. 14*

    Nonlocal gluon condensates in QCD sum rules

    Alexandr V. Pimikov🇷🇺

    Nonlocal gluon condensates are vacuum expectations of the product of gluon field strength tensors. Short-distance expansions of two-, three-, and four-gluon condensates are presented up to dimension-8 local operators. We propose a method for calculating the Wilson coefficients based on the presented expansions and the Feynman diagram technique in the background field approach. The method is demonstrated using the glueball current correlators as examples. Methodological aspects of the background field approach are discussed in relation to glueball studies within QCD sum rules. We confirm the results for Operator Product Expansion (OPE) of the two-gluon $0^{\pm +}$ glueball current correlators and calculate additional contributions coming from dimension-6 four-quark condensate and dimension-8 mixed quark-gluon condensates. The OPEs used in QCD sum rules for three-gluon $0^{\pm +}$ glueballs are revisited up to dimension-6 order.

    hep-phPRD(2022)·5 citations
15. 15*

    Data-driven evaluations of Euclidean windows to scrutinize hadronic vacuum polarization

    G. Colangelo🇨🇭 · A. X. El-Khadra🇺🇸 · M. Hoferichter🇨🇭 · A. Keshavarzi🇬🇧 · C. Lehner🇩🇪 · P. Stoffer🇨🇭 · T. Teubner🇬🇧

    In this paper, we discuss how windows in Euclidean time can be used to isolate the origin of potential conflicts between evaluations of the hadronic-vacuum-polarization (HVP) contribution to the anomalous magnetic moment of the muon in lattice QCD and from $e^{+}{e}^{-}\to \text{hadrons}$ cross-section data. We provide phenomenological comparison numbers evaluated from $e^{+}{e}^{-}\to \text{hadrons}$ data for the window quantities most commonly studied in lattice QCD, complete with the correlations among them. We discuss and evaluate modifications of window parameters that could be useful in dissecting the energy dependence of tensions in the HVP integral and emphasize that further optimizations require a precise knowledge of the full covariance matrix in lattice-QCD calculations as well.

    hep-phhep-latnucl-thPLB(2022)·145 citations
16. 16*

    The Mathematical Structure of $U$-Spin Amplitude Sum Rules

    Margarita Gavrilova🇺🇸 · Yuval Grossman🇺🇸 · Stefan Schacht🇬🇧

    We perform a systematic study of $SU(2)$ flavor amplitude sum rules with particular emphasis on $U$-spin. This study reveals a rich mathematical structure underlying the sum rules that allows us to formulate an algorithm for deriving all $U$-spin amplitude sum rules to any order of the symmetry breaking. This novel approach to deriving the sum rules does not require one to explicitly compute the Clebsch-Gordan tables, and allows for simple diagrammatic interpretation. Several examples that demonstrate the application of our novel method to systems that can be probed experimentally are provided.

    hep-phhep-exJHEP(2022)·24 citations
17. 17*

    Learning the EFT likelihood with tree boosting

    Suman Chatterjee🇦🇹 · Stefan Rohshap🇦🇹 · Robert Schöfbeck🇦🇹 · Dennis Schwarz🇦🇹

    We develop a tree boosting algorithm for collider measurements of multiple Wilson coefficients in effective field theories describing phenomena beyond the standard model of particle physics. The design of the discriminant exploits per-event information of the simulated data sets that encodes the predictions for different values of the Wilson coefficients. This ``Boosted Information Tree'' algorithm provides nearly optimal discrimination power order-by-order in the expansion in the Wilson coefficients and approaches the optimal likelihood ratio test statistic. As a proof-of-principle, we apply the algorithm to the $\text{pp}\to \text{Zh}$ process for different types of modeling.

    hep-ph24 citations
18. 18*

    Ultra-Light Pion and Baryon WIMPzilla Dark Matter

    Azadeh Maleknejad🇨🇭 · Evan McDonough🇨🇦

    We consider a dark confining gauge theory with millicharged Ultra-Light Pions (ULP) and heavy baryons as dark matter candidates. The model simultaneously realizes the ultra-light (STrongly-interacting Ultralight Millicharged Particle or "STUMP") and superheavy ("WIMPzilla") dark matter paradigms, connected by the confinement scale of the dark QCD. It is a realization of millicharged ULDM, very unlike conventional axions, and exhibits a mass splitting between the charged and neutral pions. ULPs can easily provide the observed density of the dark matter, and be cosmologically stable, for a broad range of dark QCD scales and quark masses. The dark baryons, produced via gravitational particle production or via freeze-in, provide an additional contribution to the dark matter density. Dark matter halos and boson stars in this context are generically an admixture of the three pions and heavy baryons, leading to a diversity of density profiles. That opens up the accessible parameter space of the model compared with the standard millicharged DM scenarios and can be probed by future experiments. We briefly discuss additional interesting phenomenology, such as ULP electrodynamics, and Cosmic ULP Backgrounds.

    hep-phastro-ph.COgr-qchep-thPRD(2022)·28 citations
19. 19*

    The Dark Dimension and the Swampland

    Miguel Montero🇺🇸 · Cumrun Vafa🇺🇸 · Irene Valenzuela🇪🇸

    Motivated by principles from the Swampland program, which characterize requirements for a consistent UV completion of quantum gravity, combined with observational data, we are led to a unique corner of the quantum gravity landscape. In particular, using the Distance/Duality conjecture and the smallness of dark energy, we predict the existence of a light tower of states and a unique extra mesoscopic dimension of length $l\sim {\Lambda }^{-\frac{1}{4}}\sim 10^{-6}m$, with extra massless fermions propagating on it. This automatically leads to a candidate for a tower of sterile neutrinos, and an associated active neutrino mass scale $m_{\nu }\sim ⟨H{⟩}^2{\Lambda }^{-\frac{1}{12}}{M}_{pl}^{-\frac{2}{3}}$. Moreover, assuming the mechanism for stabilization of this dark dimension leads to similar masses for active and sterile neutrinos we are led to the prediction of a Higgs vev $⟨H⟩\sim {\Lambda }^{\frac{1}{6}}{M}_{pl}^{\frac{1}{3}}$. Another prediction of the scenario is a species scale $\hat{M}\sim {\Lambda }^{\frac{1}{12}}{M}_{pl}^{\frac{2}{3}}\sim 10^9-10^{10}GeV$, corresponding to the higher-dimensional Planck scale. This energy scale may be related to the resolution of the instability of the Higgs effective potential present at a scale of $\sim 10^{11}GeV$. We also speculate about the interplay between this energy scale and the GZK limit on ultra-high energy cosmic rays.

    ↳ hep-thhep-phJHEP(2023)·214 citations
20. 20*

    Electromagnetic measurement of the temperature of quark-gluon plasma produced in central ultrarelativistic nuclear collisions

    Jean-François Paquet🇺🇸 · Steffen A. Bass🇺🇸

    Ultrarelativistic collisions of large nuclei produce a short-lived plasma of deconfined quarks and gluons. Of all the GeV-energy photons detected in these nuclear collisions, only a small number are emitted directly by the quark-gluon plasma. The characteristic near-exponential energy spectrum of these photons is often associated with an effective temperature whose interpretation is complicated by spacetime averaging, Doppler shifts and other factors. We show that the Doppler shift's effect on the slope of the photon spectrum is generally modest and can either increase or decrease the slope, in contrast to the commonly assumed blue-shifting of the photon spectrum. We make the case that a minimal degree of modelling of quark-gluon plasma expansion provides a reasonable mapping between the slope of the photon energy spectrum and the maximum temperature of the plasma, as long as the slope is extracted at a reasonably high photon energy and thermal photons can be isolated from non-thermal sources. Validating our approach using state-of-the-art numerical calculations of photon production, we highlight the challenges of contamination from non-thermal sources.

    ↳ nucl-thhep-ph9 citations
21. 21*

    Machine-learning-based prediction of parameters of secondaries in hadronic showers using calorimetric observables

    M. Chadeeva🇷🇺 · S. Korpachev🇷🇺

    The paper describes a novel neural-network-based approach to study the distributions of secondaries produced in hadronic showers using observables provided by highly granular calorimeters. The response is analysed of the highly granular scintillator-steel hadron calorimeter to negative pions with momenta from 10 to 80 GeV simulated with two physics lists from the Geant4 package version 10.3. Several global observables, which characterise different aspects of hadronic shower development, are used as inputs for a deep neural network. The network regression model is trained using a supervised learning and exploiting true information from the simulations. The trained model is applied to predict a number of neutrons and energy of neutral pions produced within a hadronic shower. The achieved performance and possible application of the model to validation of simulations are discussed.

    ↳ physics.ins-dethep-phJINST(2022)·4 citations
22. 22*

    $\eta$-glueball mixing from $N_f=2$ lattice QCD

    Xiangyu Jiang🇨🇳 · Wei Sun🇨🇳 · Feiyu Chen🇨🇳 · Ying Chen · Ming Gong🇨🇳 · Zhaofeng Liu🇨🇳 · Renqiang Zhang🇨🇳

    We perform the first lattice study on the mixing of the isoscalar pseudoscalar meson $\eta$ and the pseudoscalar glueball $G$ in the $N_f=2$ QCD at the pion mass $m_{\pi }\approx 350$ MeV. The $\eta$ mass is determined to be $m_{\eta }=714(6)(16)$ MeV. Through the Witten-Veneziano relation, this value can be matched to a mass value of $\sim 981$ MeV for the $\mathrm{SU}(3)$ counterpart of $\eta$. Based on a large gauge ensemble, the $\eta -G$ mixing energy and the mixing angle are determined to be $|x|=107(15)(2)$ MeV and $|\theta |=3.46(46{)}^{\circ }$ from the $\eta -G$ correlators that are calculated using the distillation method. We conclude that the $\eta -G$ mixing is tiny and the topology induced interaction contributes most of $\eta$ mass owing to the QCD ${\mathrm{U}}_{\mathrm{A}}(1)$ anomaly.

    ↳ hep-lathep-exhep-phPRD(2023)·25 citations
23. 23*

    Slow-Roll Inflation at N3LO

    Pierre Auclair🇧🇪 · Christophe Ringeval🇧🇪

    The next generation of cosmological observations will be sensitive to small deviations from a pure power law in the primordial power spectrum of the curvature perturbations. In the context of slow-roll inflation, these deviations are expected and correspond to the so-called running of the spectral index. Their measurement would bring as much information as the discovery of deviations from scale invariance. However, robust parameter inference requires to marginalize over any possible higher order uncertainties, which have been, up to now, not fully determined. We tackle this issue by deriving the inflationary scalar and tensor slow-roll power spectra at next-to-next-to-next to leading order (N3LO), fully expanded around an observable pivot wavenumber, for all single field inflationary models having minimal and non-minimal kinetic terms. Our result therefore encompasses string-inspired inflationary models having a varying speed of sound.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2022)·35 citations
24. 24*

    Towards the chiral phase transition in the Roberge-Weiss plane

    F. Cuteri🇩🇪 · J. Goswami🇯🇵 · F. Karsch🇩🇪 · Anirban Lahiri🇩🇪 · M. Neumann🇩🇪 · O. Philipsen🇩🇪 · Christian Schmidt🇩🇪 · A. Sciarra🇩🇪

    We discuss the interplay between chiral and center sector phase transitions that occur in QCD with an imaginary quark chemical potential $\mu =i(2n+1)\pi T/3$. Based on a finite size scaling analysis in (2+1)-flavor QCD using HISQ fermions with a physical strange quark mass and a range of light quark masses, we show that the endpoint of the line of first-order Roberge-Weiss (RW) transitions between center sectors is second order for light quark masses $m_l\ge m_s/320$, and that it belongs to the $3$-d, $Z(2)$ universality class. The operator for the chiral condensate behaves like an energy-like operator in an effective spin model for the RW phase transition. As a consequence, for any non-zero value of the quark mass, the chiral condensate will have an infinite slope at the RW phase transition temperature, $T_{RW}$. Its fluctuation, the disconnected chiral susceptibility, behaves like the specific heat in $Z(2)$ symmetric models and diverges in the infinite volume limit at the RW phase transition temperature $T_{RW}$ for any non-zero value of the light quark masses. Our analysis suggests the critical temperatures for the RW phase transition and the chiral phase transition coincide in the RW plane. On lattices with temporal extent $N_{\tau }=4$, we find in the chiral limit $T_{\chi }=T_{RW}=195(1)$MeV.

    ↳ hep-lathep-phnucl-thPRD(2022)·29 citations
25. 25*

    Variational thermal quantum simulation of the lattice Schwinger model

    Xu-Dan Xie🇨🇳 · Xingyu Guo🇨🇳 · Hongxi Xing🇨🇳 · Zheng-Yuan Xue🇨🇳 · Dan-Bo Zhang🇨🇳 · Shi-Liang Zhu🇨🇳

    Confinement of quarks due to the strong interaction and the deconfinement at high temperatures and high densities are a basic paradigm for understanding the nuclear matter. Their simulation, however, is very challenging for classical computers due to the sign problem of solving equilibrium states of finite-temperature quantum chromodynamical systems at finite density. In this paper, we propose a variational approach, using the lattice Schwinger model, to simulate the confinement or deconfinement by investigating the string tension. We adopt an ansatz that the string tension can be evaluated without referring to quantum protocols for measuring the entropy in the free energy. Results of numeral simulation show that the string tension decreases both along the increasing of the temperature and the chemical potential, which can be an analog of the phase diagram of QCD. Our work paves a way for exploiting near-term quantum computers for investigating the phase diagram of finite-temperature and finite density for nuclear matters.

    ↳ quant-phhep-lathep-phnucl-thPRD(2022)·44 citations
26. 26*

    Critical net-baryon fluctuations in an expanding system

    Grégoire Pihan🇫🇷 · Marcus Bluhm🇫🇷 · Masakiyo Kitazawa🇯🇵 · Taklit Sami🇫🇷 · Marlene Nahrgang🇫🇷

    In this work we study the consequences of a longitudinal Bjorken expansion and a Hubble-like temperature cooling scenario on a 1+1D non-linear model of the diffusive dynamics of fluctuations in the net-baryon density. The equilibrium behavior of the fluctuations is fully encoded in the temperature dependence of the susceptibilities on the crossover side both in the vicinity of the assumed location of the critical point and at vanishing baryo-chemical potential in-line with lattice QCD calculations. We demonstrate the great sensitivity of the fluctuation observables on the dynamics, in particular on the diffusion length and the freeze-out conditions. While the critical signals are visible and the critical region is broadened by the expansion, a too small diffusion length can strongly reduce the amplitude of the signals. We propose to search for significant anti-correlations of baryons at intermediate rapidity experimentally and to map out the rapidity dependence of the fourth-order cumulant, which in the presence of a critical point (and only in its presence) has a pronounced minimum at intermediate rapidities.

    ↳ nucl-thhep-phPRC(2023)·24 citations
27. 27*

    Phenomenological Motivation for Gravitational Positivity Bounds: A Case Study of Dark Sector Physics

    Toshifumi Noumi🇯🇵 · Sota Sato🇯🇵 · Junsei Tokuda🇯🇵

    Positivity bounds on scattering amplitudes provide a necessary condition for a low-energy effective field theory to have a consistent ultraviolet completion. Their extension to gravity theories has been studied in the past years aiming at application to the swampland program, showing that positivity bounds hold at least approximately even in the presence of gravity. An issue in this context is how much negativity is allowed for a given scattering process. In this paper we address importance of this rather technical issue by demonstrating that it is relevant to physics within the scope of ongoing experiments, especially in the context of dark sector physics. In particular, we provide detailed analysis of dark photon scenarios as an illustrative example. This motivates further studies on gravitational positivity bounds.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2023)·20 citations
28. 28*

    Ultraviolet Unitarity Violations in Non-minimally Coupled Scalar-Starobinsky Inflation

    Sukanta Panda🇮🇳 · Abbas Altafhussain Tinwala🇮🇳 · Archit Vidyarthi🇮🇳

    We perform the calculation for tree-level ultraviolet unitarity violation scales for scalar-$R^2$ inflation models by including an additional $R^2|\Phi {|}^2$-type term. Due to certain constraints, we resort to the Einstein frame for our calculations, where we separate our analysis between metric and Palatini formulations. We follow recent works in this line that debunk the naive predictions for unitarity violations in Higgs' inflation models to determine how to accurately estimate the behaviour of scattering amplitudes in the UV limit. Later, we work out different cases by assuming potentials corresponding to known inflation scenarios so we could predict the range of coupling parameters for which the theories would remain unitary up to the Planckian regime. We also try to find the behaviour of the scattering amplitudes for these theories during the transition from inflationary to reheating epoch.

    ↳ gr-qchep-phhep-thJCAP(2023)·9 citations
29. 29*

    Constraints on dark matter annihilation and decay from the large-scale structure of the nearby universe

    Deaglan J. Bartlett🇬🇧 · Andrija Kostić🇩🇪 · Harry Desmond🇬🇧 · Jens Jasche🇸🇪 · Guilhem Lavaux🇫🇷

    Decaying or annihilating dark matter particles could be detected through gamma-ray emission from the species they decay or annihilate into. This is usually done by modelling the flux from specific dark matter-rich objects such as the Milky Way halo, Local Group dwarfs, and nearby groups. However, these objects are expected to have significant emission from baryonic processes as well, and the analyses discard gamma-ray data over most of the sky. Here we construct full-sky templates for gamma-ray flux from the large-scale structure within $\sim$200 Mpc by means of a suite of constrained $N$-body simulations (CSiBORG) produced using the Bayesian Origin Reconstruction from Galaxies algorithm. Marginalising over uncertainties in this reconstruction, small-scale structure, and parameters describing astrophysical contributions to the observed gamma-ray sky, we compare to observations from the Fermi Large Area Telescope to constrain dark matter annihilation cross sections and decay rates through a Markov Chain Monte Carlo analysis. We rule out the thermal relic cross section for $s$-wave annihilation for all $m_{\chi }\lesssim 7\mathrm{GeV}/c^2$ at 95\% confidence if the annihilation produces gluons or quarks less massive than the bottom quark. We infer a contribution to the gamma-ray sky with the same spatial distribution as dark matter decay at $3.3\sigma$. Although this could be due to dark matter decay via these channels with a decay rate $\Gamma \approx 6\times 10^{-28}{\mathrm{s}}^{-1}$, we find that a power-law spectrum of index $p=-2.75_{-0.46}^{+0.71}$, likely of baryonic origin, is preferred by the data.

    ↳ astro-ph.COastro-ph.GAastro-ph.HEhep-phPRD(2022)·33 citations
30. 30*

    Searches for Connections between Dark Matter and High-Energy Neutrinos with IceCube

    R. Abbasi · M. Ackermann · J. Adams · J. A. Aguilar · M. Ahlers · M. Ahrens · J.M. Alameddine · A. A. Alves Jr. · N. M. Amin · K. Andeen · T. Anderson · G. Anton and 368 other authors

    In this work, we present the results of searches for signatures of dark matter decay or annihilation into Standard Model particles, and secret neutrino interactions with dark matter. Neutrinos could be produced in the decay or annihilation of galactic or extragalactic dark matter. Additionally, if an interaction between dark matter and neutrinos exists then dark matter will interact with extragalactic neutrinos. In particular galactic dark matter will induce an anisotropy in the neutrino sky if this interaction is present. We use seven and a half years of the High-Energy Starting Event (HESE) sample data, which measures neutrinos in the energy range of approximately 60 TeV to 10 PeV, to study these phenomena. This all-sky event selection is dominated by extragalactic neutrinos. For dark matter of $\sim$ 1 PeV in mass, we constrain the velocity-averaged annihilation cross section to be smaller than $10^{-23}$cm${}^3$/s for the exclusive ${\mu }^{+}{\mu }^{-}$ channel and $10^{-22}$ cm${}^3$/s for the $b\bar{b}$ channel. For the same mass, we constrain the lifetime of dark matter to be larger than $10^{28}$ s for all channels studied, except for decaying exclusively to $b\bar{b}$ where it is bounded to be larger than $10^{27}$ s. Finally, we also search for evidence of astrophysical neutrinos scattering on galactic dark matter in two scenarios. For fermionic dark matter with a vector mediator, we constrain the dimensionless coupling associated with this interaction to be less than 0.1 for dark matter mass of 0.1 GeV and a mediator mass of $10^{-4}$ GeV. In the case of scalar dark matter with a fermionic mediator, we constrain the coupling to be less than 0.1 for dark matter and mediator masses below 1 MeV.

    ↳ hep-exastro-ph.HEhep-phJCAP(2023)·51 citations
31. 31*

    Deciphering the Maximal Transcendentality Principle via Bootstrap

    Yuanhong Guo🇨🇳 · Qingjun Jin🇨🇳 · Lei Wang🇨🇳 · Gang Yang🇨🇳

    We prove the principle of maximal transcendentality for a class of form factors, including the general two-loop minimal form factors, the two-loop three-point form factor of $\mathrm{tr}(F^2)$, and the two-loop four-point form factor of $\mathrm{tr}(F^3)$. Our proof is based on a recently developed bootstrap method using the representation of master integral expansions, together with some unitarity cuts that are universal in general gauge theories. The maximally transcendental parts of the two-loop four-gluon form factor of $\mathrm{tr}(F^3)$ are obtained for the first time in both planar $\mathcal{N}=4$ SYM and pure YM theories. This form factor can be understood as the Higgs-plus-four-gluon amplitudes involving a dimension-seven operator in the Higgs effective theory. In this case, we find that the maximally transcendental part of the $\mathcal{N}=4$ SYM result is different from that of pure YM, and the discrepancy is due to the gluino-loop contributions in $\mathcal{N}=4$ SYM. In contrast, the scalar-loop contributions have no maximally transcendental parts. Thus, the maximal transcendentality principle still holds for the form factor results in $\mathcal{N}=4$ SYM and QCD, after a proper identification of the fundamental quarks and adjoint gluinos as $n_f\to 4N_c$. This seems to be the first example of the maximally transcendental principle that involves fermion-loop contributions. As another intriguing observation, we find that the four-point form factor of the half-BPS $\mathrm{tr}({\varphi }^3)$ operator is precisely a building block in the form factor of $\mathrm{tr}(F^3)$.

    ↳ hep-thhep-phJHEP(2022)·9 citations
32. 32*

    There is no electroweak horizon problem

    James M. Cline🇨🇦

    Contrary to a recent assertion [Fulvio Melia "The electroweak horizon problem" 2022], there is no electroweak horizon problem.

    ↳ physics.gen-phastro-ph.COhep-phPhys.Dark Univ.(2022)·1 citation

* 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.