Tue·Aug 10, 2021Tuesday·August 10, 2021

1. 01*

   Extending the Reach of Leptophilic Boson Searches at DUNE and MiniBooNE with Bremsstrahlung and Resonant Production

   Francesco Capozzi🇺🇸 · Bhaskar Dutta🇺🇸 · Gajendra Gurung🇺🇸 · Wooyoung Jang🇺🇸 · Ian M. Shoemaker🇺🇸 · Adrian Thompson🇺🇸 · Jaehoon Yu🇺🇸

   New gauge bosons coupling to leptons are simple and well-motivated extensions of the Standard Model. We study the sensitivity to gauged $L_{\mu }-L_e$, $L_e-L_{\tau }$ and $L_{\mu }-L_{\tau }$ both with the existing beam dump mode data of MiniBooNE and with the DUNE near detector. We find that including bremsstrahlung and resonant production of $Z^{\prime }$ which decays to $e^{\pm }$ and ${\mu }^{\pm }$ final states leads to a significant improvement in existing bounds, especially for $L_{\mu }-L_e$ and $L_e-L_{\tau }$ for DUNE while competitive constraints can be achieved with the existing data from the MiniBooNE's beam dump run.

   hep-phhep-exPRD(2021)·14 citations
2. 02*

   Radiative corrections to semileptonic beta decays: Progress and challenges

   Chien-Yeah Seng🇩🇪

   We review some recent progress in the theory of electroweak radiative corrections in semileptonic decay processes. The resurrection of the so-called Sirlin's representation based on current algebra relations permits a clear separation between the perturbatively-calculable and incalculable pieces in the $\mathcal{O}(G_F\alpha )$ radiative corrections. The latter are expressed as compact hadronic matrix elements that allow systematic non-perturbative analysis such as dispersion relation and lattice QCD. This brings substantial improvements to the precision of the electroweak radiative corrections in semileptonic decays of pion, kaon, free neutron and $J^P=0^{+}$ nuclei that are important theory inputs in precision tests of the Standard Model. Unresolved issues and future prospects are discussed.

   hep-phhep-exhep-latnucl-ex+1Particles(2021)·29 citations
3. 03*

   Searching a systematics for nonfactorizable contribution to B-and B0 mesons

   Maninder Kaur🇮🇳 · Supreet Pal Singh🇮🇳 · R. C. Verma🇮🇳

   Two-body weak decays / and are examined under isospin analysis to study nonfactorizable contributions. After extracting the strong phases and obtaining the factorizable contributions from spectator-quark diagrams for Nc=3, we determine nonfactorizable isospin amplitudes from the experimental data for these modes. Our results support the universality of ratio of nonfactorizable isospin reduced amplitudes for these decays within experimental errors. In order to show that this systematics is not coincidental, we also plot our results w. r. t. this ratio.

   hep-phCPC(2022)·7 citations
4. 04*

   Unified formalism for electromagnetic and gravitational probes: densities

   Adam Freese🇺🇸 · Gerald A. Miller🇺🇸

   The use of light front coordinates allows a fully relativistic description of a hadron's spatial densities to be obtained. These densities must be two-dimensional and transverse to a chosen spatial direction. We explore their relationship to the three-dimensional, non-relativistic densities, with a focus on densities associated with the energy momentum tensor. The two-dimensional non-relativistic densities can be obtained from the light front densities through a non-relativistic limit, and can subsequently be transformed into three-dimensional non-relativistic densities through an inverse Abel transform. However, this operation is not invertible, and moreover the application of the inverse Abel transform to the light front densities does not produce a physically meaningful result. We additionally find that the Abel transforms of so-called Breit-frame densities generally differ significantly from the true light front densities. Numerical examples are provided to illustrate the various differences between the light front, Breit frame, and non-relativistic treatment of densities.

   hep-phnucl-thPRD(2022)·65 citations
5. 05*

   Towards a study of the effects of dynamical factorization breaking at LHCb

   Jordan Roth🇺🇸

   The factorization of short-distance partonic cross-sections from universal long-distance kinematic distributions is fundamental to phenomenology at hadron colliders. It has been predicted however that observables sensitive to momenta transverse to the direction of an energetic parton cannot be factorized in the usual way, even at high energies. It should be possible to study this factorization breaking using Z+jet production in high-energy proton-proton collisions by studying azimuthal correlations between a Z boson and associated charged hadrons. A plan to perform this measurement with data collected by LHCb will be discussed, along with related work.

   hep-phhep-ex0 citations
6. 06*

   Factorization in hard exclusive processes. Computation of one-loop corrections to the diphoton photoproduction on proton

   Oskar Grocholski🇵🇱

   Generalized Parton Distributions (GPDs) carry information on the internal structure of hadrons such as the angular momentum of quarks and gluons, or their spacelike distribution. They can be experimentally studied in exclusive experiments with hadrons, i.e. processes in which all initial and final states are measured. The tool that creates the necessary bridge between the theoretical predictions and the experiments is the collinear factorization. It allows disentangling perturbatively computable parts of the amplitude, which describes interactions of quarks and gluons with the external particles, from the non-perturbative quantities, which are identified as GPDs. In this work, I extend the theoretical analysis of the process photoproduction of photon pairs on a proton to the next-to-leading order in perturbative Quantum Chromodynamics within the framework of collinear factorization. I give the proof that all collinear divergences which arise in one-loop computations cancel at the level of the amplitude. This result enlarges the family of reactions, which can be studied using the collinear factorization by processes of the type $2\to 3$, which have not been previously studied within this theoretical framework beyond the leading QCD order. Furthermore, I compute the full form of the amplitude of the discussed process at the one-loop order. That improves the accuracy of theoretical predictions for this experiment, which may be used for planning future experiments in JLAB or EIC.

   hep-phhep-th1 citation
7. 07*

   Forming Molecular States with Hadronic Rescattering

   Philip Ilten🇺🇸 · Marius Utheim🇸🇪

   A method for modelling the prompt production of molecular states using the hadronic rescattering framework of the general-purpose Pythia event generator is introduced. Production cross sections of possible exotic hadronic molecules via hadronic rescattering at the LHC are calculated for the ${\chi }_{c1}(3872)$ resonance, a possible tetraquark state, as well as three possible pentaquark states, $P_c^{+}(4312)$, $P_c^{+}(4440)$, and $P_c^{+}(4457)$. For the $P_c^{+}$ states, the expected cross section from ${\Lambda }_b$ decays is compared to the hadronic-rescattering production. The ${\chi }_{c1}(3872)$ cross section is compared to the fiducial ${\chi }_{c1}(3872)$ cross-section measurement by LHCb and found to contribute at a level of O(1%). Finally, the expected yields of $P_c^{+}$ production from hadronic rescattering during Run 3 of LHCb are estimated. The prompt background is found to be significantly larger than the prompt $P_c^{+}$ signal from hadronic rescattering.

   hep-phnucl-thEPJA(2022)·29 citations
8. 08*

   Hadron Interactions for Arbitrary Energies and Species, with Applications to Cosmic rays

   Torbjörn Sjöstrand🇸🇪 · Marius Utheim🇸🇪

   The Pythia event generator is used in several contexts to study hadron and lepton interactions, notably $pp$ and $p\bar{p}$ collisions. In this article we extend the hadronic modelling to encompass the collision of a wide range of hadrons $h$ with either a proton or a neutron, or with a simplified model of nuclear matter. To this end we model $hp$ total and partial cross sections as a function of energy, and introduce new parton distribution functions for a wide range of hadrons, as required for a proper modelling of multiparton interactions. The potential usefulness of the framework is illustrated by a simple study of the evolution of cosmic rays in the atmosphere, and by an even simpler one of shower evolution in a solid detector material. The new code will be made available for future applications.

   hep-phastro-ph.HEEPJC(2022)·26 citations
9. 09*

   Hadron spectroscopy using the light-front holographic Schrödinger equation and the 't Hooft equation

   Mohammad Ahmady🇨🇦 · Satvir Kaur🇮🇳 · Sugee Lee MacKay🇨🇦 · Chandan Mondal🇨🇳 · Ruben Sandapen🇨🇦

   Light-front holographic QCD provides a successful first approximation to hadron spectroscopy in the chiral limit of $(3+1)$-dim light-front QCD, where a holographic Schrödinger-like equation, with an emerging confining scale, $\kappa$, governs confinement in the transverse direction. In its supersymmetric formulation, light-front holography predicts that each baryon has two superpartners: a meson and a tetraquark, with their degenerate masses being generated by the same scale, $\kappa$. In nature, this mass degeneracy is lifted by chiral symmetry breaking and longitudinal confinement. In this paper, we show that the latter can be successfully captured by the 't Hooft equation of $(1+1)$-dim, large $N_c$, QCD. Together, the holographic Schrödinger equation and the 't Hooft equation, provide a good global description of the data across the full hadron spectrum with a universal $\kappa$.

   hep-phPRD(2021)·32 citations
10. 10*

    Proton and deuteron mass radii from near-threshold $\varphi$-meson photoproduction

    Rong Wang🇨🇳 · Wei Kou🇨🇳 · Chengdong Han🇨🇳 · Jarah Evslin🇨🇳 · Xurong Chen🇨🇳

    We analyze the exclusive $\varphi$-meson photoproduction on both hydrogen and deuterium targets based on the published data of CLAS, SAPHIR and LEPS collaborations. A dipole-form scalar gravitational form factor is applied to describe the $|t|$-dependence of the differential cross section. Based on the average of all the near-threshold data from CLAS, SAPHIR and LEPS, we find that the proton and deuteron mass radii are $0.75\pm 0.02$ fm and $1.95\pm 0.19$ fm respectively. The coherent and near-threshold quarkonium photoproduction seems to be sensitive to the radius of the hadronic system. The vector-meson-dominance model together with a low-energy QCD theorem well describe the data of near-threshold $\varphi$ photoproduction on the hadronic systems.

    hep-phPRD(2021)·15 citations
11. 11*

    Electroweak Baryogenesis in the CP-Violating Two-Higgs Doublet Model

    Philipp Basler · Margarete Mühlleitner · Jonas Müller

    Recently we presented the upgrade of our code BSMPT for the calculation of the electroweak phase transition (EWPT) to BSMPT v2 which now includes the computation of the baryon asymmetry of the universe (BAU) in the CP-violating 2-Higgs-Doublet Model (C2HDM). In this paper we use {\tt BSMPT v2} to investigate the size of the BAU that is obtained in the C2HDM with the two implemented approaches FH and VIA to derive the transport equations, by taking into account all relevant theoretical and experimental constraints. We identify similarities and differences in the results computed with the two methods. In particular, we analyse the dependence of the obtained BAU on the parameters relevant for successful baryogenesis. Our investigations allow us to pinpoint future directions for improvements both in the computation of the BAU and in possible avenues taken for model building.

    hep-phEPJC(2023)·69 citations
12. 12*

    Precise Phase Structure in Four-fermion Interaction Model on Torus

    Tomohiro Inagaki🇯🇵 · Yamato Matsuo🇯🇵 · Hiromu Shimoji🇯🇵

    We investigate finite-size effects on chiral symmetry breaking in a four-fermion interaction model at a finite temperature and a chemical potential. Applying the imaginary time formalism, the thermal quantum field theory is constructed on an $S^1$ in the imaginary time direction. In this paper, the finite-size effect is introduced by a compact $S^1$ spatial direction with a $\mathrm{U}(1)$-valued boundary condition. Thus, we study the model on a ${\mathbb{R}}^{D-2}\times S^1\times S^1$ torus. Phase diagrams are obtained by evaluating the local minima of the effective potential in the leading order of the $1/N$ expansion. From the grand potential, we calculate the particle number density and the pressure, then we illustrate the correspondence with the phase structure. We obtain a stable size for which the sign of the pressure flips from negative to positive as the size decreases. Furthermore, the finite chemical potential expands the parameter range that the stable size exists.

    hep-phhep-thPTEP(2022)·8 citations
13. 13*

    A model with light and heavy scalars in view of the effective theory

    Apriadi Salim Adam (BRIN)🇮🇩 · Yuta Kawamura (Hiroshima univ.)🇯🇵 · Takuya Morozumi (Hiroshima univ.)🇯🇵

    The low energy effective potential for the model with a light scalar and a heavy scalar is derived. We perform the path integration for both heavy and light scalars and derive the low energy effective potential in terms of only the light scalar. The effective potential is independent of the renormalization scale approximately. By setting the renormalization scale equal to the mass of the heavy scalar, one finds the corrections with the logarithm of the ratio of the two scalar masses. The large logarithm is summed with the renormalization group (RG) and the RG improved effective potential is derived. The improved effective potential includes the one-loop correction of the heavy scalar and the leading logarithmic corrections due to the light scalar. We study the correction to the vacuum expectation value of the light scalar and the dependence on the mass of the heavy scalar.

    hep-phhep-thPTEP(2022)·2 citations
14. 14*

    Quark Sivers Function at Small $x$: Spin-Dependent Odderon and the Sub-Eikonal Evolution

    Yuri V. Kovchegov🇺🇸 · M. Gabriel Santiago🇺🇸

    We apply the formalism developed earlier for studying transverse momentum dependent parton distribution functions (TMDs) at small Bjorken $x$ to construct the small-$x$ asymptotics of the quark Sivers function. First, we explicitly construct the complete fundamental "polarized Wilson line" operator to sub-sub-eikonal order: this object can be used to study a variety of quark TMDs at small-$x$. We then express the quark Sivers function in terms of dipole scattering amplitudes containing various components of the "polarized Wilson line" and show that the dominant (eikonal) term which contributes to the quark Sivers function at small $x$ is the spin-dependent odderon, confirming the recent results of Dong, Zheng and Zhou. Our conclusion is also similar to the case of the gluon Sivers function derived by Boer, Echevarria, Mulders and Zhou (see also the work by Szymanowski and Zhou). We also analyze the sub-eikonal corrections to the quark Sivers function using the constructed "polarized Wilson line" operator. We derive new small-$x$ evolution equations re-summing double-logarithmic powers of ${\alpha }_s{\ln }^2(1/x)$ with ${\alpha }_s$ the strong coupling constant. We solve the corresponding novel evolution equations in the large-$N_c$ limit, obtaining a sub-eikonal correction to the spin-dependent odderon contribution. We conclude that the quark Sivers function at small $x$ receives contributions from two terms and is given by \begin{align} f_{1 \: T}^{\perp \: q} (x, k_T^2) = C_O (x, k_T^2) \, \frac{1}{x} + C_1 (k_T^2) \, \left( \frac{1}{x} \right)^0 + \ldots \end{align} with the function $C_O(x,k_T^2)$ varying slowly with $x$ and the ellipsis denoting the sub-asymptotic and sub-sub-eikonal (order-$x$) corrections.

    hep-phhep-exnucl-exnucl-thJHEP(2021)·59 citations
15. 15*

    Quantum Induced Broadening- A Challenge For Cosmic Neutrino Background Discovery

    Shmuel Nussinov🇮🇱 · Zohar Nussinov🇺🇸

    A recent preprint by Cheipesh {\it et al.} pointed out that the zero-point motion of Tritium atoms bound to Graphene may blur the measured energies of $\beta$ electrons. Smearing due to zero point motion is well known. Such an effect features in studies of the $\beta$ spectrum expected in experiments like KATRIN using diatomic Tritium. The recent preprint may, however, challenge new planned experiments seeking to discover the Cosmic Neutrino Background (CNB) neutrinos (and/or other neutrinos of masses smaller than $0.1$ eV) which plan to use Tritium adsorbed onto Graphene or other materials. Our paper clarifies these issues and examines the more general problem of smearing induced by quantum uncertainty. We find that the effect of Cheipesh {\it et al.} is reduced considerably. The importance of the chemical evolution of the ${}^3$H atom hosting the Tritium nucleus into a tightly bound neutral ${}^3$He atom is emphasized. We estimate the excess blurring caused by the dense spectrum near the lowest state of the Graphene or other hosts of the Tritium atom, generated by the electronic response to the "sudden" escape of the $\beta$ electron. Our analysis suggests yet larger effects and difficulties facing many experiments searching for small mass neutrinos. We speculate on a possible experimental setup which could minimize quantum broadening.

    hep-phastro-ph.COcond-mat.mtrl-sciPRD(2022)·30 citations
16. 16*

    A general-mass scheme for prompt charm production at hadron colliders

    Keping Xie🇺🇸 · John M. Campbell🇺🇸 · Pavel M. Nadolsky🇺🇸

    In these proceedings, we apply the recently developed S-ACOT-MPS factorization scheme at the next-to-leading order to prompt charm production at hadron colliders. It provides a good agreement with experimental data on charm meson production measured by LHCb at 7 and 13 TeV. The low-$p_T$ data are on the margins of the theoretical error bands, emphasizing the importance of including contributions beyond the next-to-leading order.

    hep-phhep-exnucl-thSciPost Phys.Proc.(2022)·12 citations
17. 17*

    Probing charmonium-like XYZ states in hadron-hadron ultraperipheral collisions and electron-proton scattering

    Ya-Ping Xie🇨🇳 · Xiao-Yun Wang🇨🇳 · Xurong Chen🇨🇳

    Exclusive production of charmonium-like XYZ states in hadron-hadron ultraperipheral collisions(UPCs) and electron-proton scattering is studied employing effective Lagrangian method. Total cross sections and rapidity distributions of charmonium-like XYZ states are obtained in hadron-hadron UPCs and electron-proton scattering process. These predictions can be applied to estimate the observed event number of exclusive charmonium-like XYZ states in hadron-hadron UPCs and electron-proton scattering. The results indicate that it is significant to search $X(3872)$ and $Z_c^{+}(3900)$ in pA UPCs and Electron-Ion Collider in China will be an advantage platform to observe XYZ states in the future.

    hep-phEPJC(2021)·6 citations
18. 18*

    Analytic results for two-loop planar master integrals for Bhabha scattering

    Claude Duhr🇩🇪 · Vladimir A. Smirnov🇷🇺 · Lorenzo Tancredi🇬🇧

    We analytically evaluate the master integrals for the second type of planar contributions to the massive two-loop Bhabha scattering in QED using differential equa- tions with canonical bases. We obtain results in terms of multiple polylogarithms for all the master integrals but one, for which we derive a compact result in terms of elliptic mul- tiple polylogarithms. As a byproduct, we also provide a compact analytic result in terms of elliptic multiple polylogarithms for an integral belonging to the first family of planar Bhabha integrals, whose computation in terms of polylogarithms was addressed previously in the literature.

    hep-phhep-thJHEP(2021)·29 citations
19. 19*

    Running coupling constant at finite chemical potential and magnetic field from holography

    Xun Chen🇨🇳 · Lin Zhang🇨🇳 · Defu Hou🇨🇳

    According to the gauge/gravity duality, we use an Einstein-Maxwell-dilaton(EMD) model to study the running coupling constant at finite chemical potential and magnetic field. First, we calculate the effect of temperature on the running coupling constant and find the results are in consistent with lattice qualitatively. Subsequently, we calculate the effect of chemical potential and magnetic field on running coupling. It is found that the chemical potential and magnetic field both suppress the running coupling constant, however, the effect of magnetic field is slightly larger than chemical potential for a fixed temperature. Compared with the confinement phase, the magnetic field has a large influence on the running coupling in the deconfinement phase.

    hep-phCPC(2022)·24 citations
20. 20*

    Proton gravitational form factors in a light-front quark-diquark model

    Dipankar Chakrabarti🇮🇳 · Chandan Mondal🇨🇳 · Asmita Mukherjee🇮🇳 · Sreeraj Nair🇨🇳 · Xingbo Zhao🇨🇳

    We present a recent calculation of the gravitational form factors (GFFs) of proton using the light-front quark-diquark model constructed by the soft-wall AdS/QCD. The four GFFs $A(Q^2)$ , $B(Q^2)$ , $C(Q^2)$ and $\bar{C}(Q^2)$ are calculated in this model. We also show the pressure and shear distributions of quarks inside the proton. The GFFs, $A(Q^2)$ and $B(Q^2)$ are found to be consistent with the lattice QCD, while the qualitative behavior of the $D$-term form factor is in agreement with the extracted data from the deeply virtual Compton scattering (DVCS) experiments at JLab, the lattice QCD, and the predictions of different phenomenological models.

    hep-phSciPost Phys.Proc.(2022)·7 citations
21. 21*

    Nucleon structure from basis light-front quantization

    Siqi Xu🇨🇳 · Chandan Mondal🇨🇳 · Jiangshan Lan🇨🇳 · Xingbo Zhao🇨🇳 · Yang Li🇨🇳 · James P. Vary🇺🇸

    We produce the light-front wave functions (LFWFs) of the nucleon from a basis light-front ap- proach in the leading Fock sector representation. We solve for the mass eigenstates from a light-front effective Hamiltonian, which includes a confining potential adopted from light-front holography in the transverse direction, a longitudinal confinement, and a one-gluon exchange interaction with fixed coupling. We then employ the LFWFs to obtain the electromagnetic and axial form factors, the par- ton distribution functions (PDFs) and the generalized parton distribution functions for the nucleon. The electromagnetic and axial form factors of the proton agree with the experimental data, whereas the neutron form factors deviate somewhat from the experiments in the low momentum transfer region. The unpolarized, the helicity, and the transversity valence quark PDFs, after QCD scale evolution, are fairly consistent with the global fits to the data at the relevant experimental scales. The helicity asymmetry for the down quark also agrees well with the measurements, however, the asymmetry for the up quark shows a deviation from the data, especially in the small x region. We also find that the tensor charge agrees well with the extracted data and the lattice QCD predictions, while the axial charge is somewhat outside the experimental error bar. The electromagnetic radii of the proton, the magnetic radius of the neutron, and the axial radius are in excellent agreement with the measurements, while the neutron charge radius deviates from experiment.

    hep-phhep-thnucl-thPRD(2021)·93 citations
22. 22*

    Deep Learning Searches for Vector-Like Leptons at the LHC and Electron/Muon Colliders

    António P. Morais🇵🇹 · António Onofre🇵🇹 · Felipe F. Freitas🇵🇹 · João Gonçalves🇵🇹 · Roman Pasechnik🇸🇪 · Rui Santos🇵🇹

    The discovery potential of both singlet and doublet vector-like leptons (VLLs) at the Large Hadron Collider (LHC) as well as at the not-so-far future muon and electron machines is explored. The focus is on a single production channel for LHC direct searches while double production signatures are proposed for the leptonic colliders. A Deep Learning algorithm to determine the discovery (or exclusion) statistical significance at the LHC is employed. While doublet VLLs can be probed up to masses of 1 TeV, their singlet counterparts have very low cross sections and can hardly be tested beyond a few hundreds of GeV at the LHC. This motivates a physics-case analysis in the context of leptonic colliders where one obtains larger cross sections in VLL double production channels, allowing to probe higher mass regimes otherwise inaccessible even to the LHC high-luminosity upgrade.

    hep-phEPJC(2023)·10 citations
23. 23*

    Spectroscopy of all charm tetraquark states

    Rohit Tiwari🇮🇳 · D P Rathaud🇮🇳 · A K Rai🇮🇳

    The mass spectra of all-charm tetraquark states with the [cc][$\bar{c}\bar{c}$] quark configuration are investigated. The coulomb plus linear potential is used in conjunction with the relativistic mass correction term $\mathcal{O}(\frac{1}{m})$. To determine the fitting parameters for all-charm tetraquarks states [cc][$\bar{c}\bar{c}$], we first calculate the mass spectra of charmonia [c$\bar{c}$] and its decay constants ($f_{P/V}^2$). We estimated the masses of the tetraquark states in their ground and radially excited states. For mass spectra of tetraquark states, we also included spin-spin, spin-orbital, and tensor interactions. The mass spectra of charmonia produced in this study are reasonably consistent with experimental and theoretical predictions made by others, whilst the mass spectra of the tetraquark states are consistent with previous theoretical predictions. We propose that the X(6900) state, which has a mass range of 6.2 - 6.9 GeV and was recently detected by LHCb, has the quantum numbers $0^{-+}$, $1^{-+}$, $2^{-+}$ and belongs to the P-wave of the all-cham tetraquark state.

    hep-phIndian J.Phys.(2023)·53 citations
24. 24*

    Exploring neutrino masses, $(g-2{)}_{\mu ,e}$ in type I+II seesaw in $L_e^{}-L_{\alpha }^{}$ gauge extended model

    Papia Panda🇮🇳 · Priya Mishra🇮🇳 · Mitesh Kumar Behera🇮🇳 · Shivaramakrishna Singirala🇮🇳 · Rukmani Mohanta🇮🇳

    This paper aims to explore the implications of $U(1{)}_{L_e-L_{\alpha }}$ gauge symmetries, where $\alpha =\tau ,\mu$, in the neutrino sector through the type-(I+II) seesaw mechanisms. To achieve such a hybrid framework, we include a scalar triplet and three right-handed neutrinos. The model can successfully account for the active neutrino masses, mixing angles, mass squared differences, and the CP-violating phase within the $3\sigma$ bounds of NuFit v5.2 neutrino oscillation data. The presence of new gauge boson at the MeV scale provides an explanation for the muon and electron $(g-2)$ within the confines of their experimental limits. Furthermore, we scrutinize the proposed models in the context of upcoming long-baseline neutrino experiments such as DUNE, P2SO, T2HK, and T2HKK. The findings reveal that P2SO and T2HK have the ability to probe both the models in their $5\sigma$ allowed oscillation parameter region, whereas DUNE and T2HKK can conclusively test only model with $U(1{)}_{L_e-L_{\mu }}$- symmetry within their $5\sigma$ parameter space if the true values of the oscillation parameters remain consistent with NuFit v5.2.

    hep-phUniverse(2024)·6 citations
25. 25*

    Drell-Yan transverse spectra at the LHC: a comparison of parton branching and analytical resummation approaches

    Aron Mees van Kampen🇧🇪

    I report on precision comparisons of theoretical predictions for Drell-Yan (DY) transverse momentum spectra from two approaches: the analytical resummation approach based on Collins-Soper-Sterman (CSS) formalism and the parton branching (PB) approach to the evolution of transverse momentum dependent (TMD) parton distributions.

    hep-phSciPost Phys.Proc.(2022)·6 citations
26. 26*

    Nucleon and pion PDFs: large-x asymptotics meets functional mimicry

    Aurore Courtoy🇲🇽 · Pavel M. Nadolsky🇺🇸

    We review strategies to unveil the primordial large-$x$ structure of the nucleons as well as the pion from hard-scattering experiments. Ideas are presented for learning about the $x\to 1$ limit of nonperturbative QCD dynamics at energy scales of order 1 GeV from collider experiments at much higher scales. The behavior of parton distributions at $x\to 1$ predicted by the quark counting rules and other low-energy theoretical approaches is contrasted with phenomenological PDFs. Polynomial mimicry of PDF parametrizations is one of many factors that influence the apparent power of the $(1-x)$ falloff. We discuss implications of the mimicry for the large-$x$ falloff of the pion PDFs.

    hep-phSciPost Phys.Proc.(2022)·6 citations
27. 27*

    Phenomenological extraction of a universal TMD fragmentation function from single hadron production in $e^{+}{e}^{-}$ annihilations

    M. Boglione🇮🇹 · J.O. Gonzalez-Hernandez🇮🇹 · A. Simonelli🇮🇹

    Factorizing the cross section for single hadron production in $e^{+}{e}^{-}$ annihilations, differential in $z_h$, $P_T$ and thrust, is a highly non trivial task. We have devised a factorization scheme that allows us to recast the $e^{+}{e}^{-}\to hX$ cross section in the convolution of a perturbatively calculable coefficient and a universal Transverse Momentum Dependent (TMD) Fragmentation Function (FF). The predictions obtained from our NLO-NLL perturbative computation, together with a simple ansatz to model the non-perturbative part of the TMD, are applied to the experimental measurements of the BELLE Collaboration for the phenomenological extraction of this process independent TMD FF.

    hep-phSciPost Phys.Proc.(2022)·2 citations
28. 28*

    Small cosmological constant from a peculiar inflaton potential

    Wen Yin🇯🇵

    We propose a novel scenario to explain the small cosmological constant (CC) by a finely tuned inflaton potential. The tuned shape is stable under radiative corrections, and our setup is technically natural. The peculiar po- tential approximately satisfies the following conditions: the inflation is eternal if CC is positive, and not eternal if CC is negative. By introducing a slowly varying CC from a positive value to a negative value, the dominant volume of the Universe after the inflation turns out to have a vanishingly small CC. The scenario does not require eternal inflation but the e-folding number is exponentially large and the inflation scale should be low enough. The scenario can have a consistent thermal history, but the present equation of state of the Universe is predicted to differ from the prediction of the {\Lambda}CDM model. A concrete model with a light scalar field is studied.

    hep-phastro-ph.COgr-qcPRD(2022)·22 citations
29. 29*

    Electroweak baryogenesis from light fermion sources: a critical study

    James M. Cline🇨🇦 · Benoit Laurent🇨🇦

    Electroweak baryogenesis (EWBG) is sourced by nonstandard $CP$-violating interactions of the Higgs boson with fermions, usually taken to be the top quark, enhanced by its large Yukawa coupling. Numerous papers have studied EWBG sourced by lighter fermions, including the tau lepton and off-diagonal quark mass terms. We critically reassess the viability of EWBG in these scenarios, comparing the predictions based on the semiclassical (WKB) formalism for the source term to those from the VEV insertion approximation (VIA), using updated values for the collision terms, and clarifying discrepancies in the definition of the weak sphaleron rate. The VIA systematically predicts a baryon asymmetry that is orders of magnitude larger than the WKB formalism. We trace this to the differing shapes of the $CP$-violating source terms in the two formalisms, showing that the additional spatial derivative in the WKB source term causes large cancellations when it is integrated over the bubble wall profile. An important exception is a source term from $c$-$t$ quark mixing, where the WKB prediction also allows for a realistically large baryon asymmetry. In contrast, the analogous $b$-$s$ mixing source is found to be orders of magnitude too small.

    hep-phastro-ph.COPRD(2021)·64 citations
30. 30*

    Symmetries, Safety, and Self-Supervision

    Barry M. Dillon🇩🇪 · Gregor Kasieczka🇩🇪 · Hans Olischlager🇩🇪 · Tilman Plehn🇩🇪 · Peter Sorrenson🇩🇪 · Lorenz Vogel🇩🇪

    Collider searches face the challenge of defining a representation of high-dimensional data such that physical symmetries are manifest, the discriminating features are retained, and the choice of representation is new-physics agnostic. We introduce JetCLR to solve the mapping from low-level data to optimized observables though self-supervised contrastive learning. As an example, we construct a data representation for top and QCD jets using a permutation-invariant transformer-encoder network and visualize its symmetry properties. We compare the JetCLR representation with alternative representations using linear classifier tests and find it to work quite well.

    hep-phSciPost Phys.(2022)·88 citations
31. 31*

    Thermal axion production at low temperatures: a smooth treatment of the QCD phase transition

    Francesco D'Eramo🇮🇹 · Fazlollah Hajkarim🇮🇹 · Seokhoon Yun🇮🇹

    We study thermal axion production around the confinement scale. At higher temperatures, we extend current calculations to account for the masses of heavy quarks, whereas we quantify production via hadron scattering at lower temperatures. Matching our results between the two opposite regimes provides us with a continuous axion production rate across the QCD phase transition. We employ such a rate to quantify the axion contribution to the effective number of neutrino species.

    hep-phastro-ph.COPRL(2022)·81 citations
32. 32*

    Air shower genealogy for muon production

    Maximilian Reininghaus🇩🇪 · Ralf Ulrich🇩🇪 · Tanguy Pierog🇩🇪

    Measurements of the muon content of extensive air showers at the highest energies show discrepancies compared to simulations as large as the differences between proton and iron. This so-called muon puzzle is commonly attributed to a lack of understanding of the hadronic interactions in the shower development. Furthermore, measurements of the fluctuations of muon numbers suggest that the discrepancy is likely a cumulative effect of interactions of all energies in the cascade. A feature of the air shower simulation code CORSIKA 8 allows us to access all previous generations of final-state muons up to the first interaction. With this technique, we study the influence of interactions happening at any intermediate stage in the cascade on muons depending on their lateral distance in a quantitative way and compare our results with predictions of the Heitler-Matthews model.

    ↳ astro-ph.HEhep-phPoS(2021)·12 citations
33. 33*

    BICEP / Keck XIV: Improved constraints on axion-like polarization oscillations in the cosmic microwave background

    BICEP/Keck Collaboration: P. A. R. Ade🇬🇧 · Z. Ahmed🇺🇸 · M. Amiri🇨🇦 · D. Barkats🇺🇸 · R. Basu Thakur🇺🇸 · C. A. Bischoff🇺🇸 · D. Beck🇺🇸 · J. J. Bock🇺🇸 · H. Boenish🇺🇸 · E. Bullock🇺🇸 · V. Buza🇺🇸 · J. R. Cheshire IV🇺🇸 and 79 other authors

    We present an improved search for axion-like polarization oscillations in the cosmic microwave background (CMB) with observations from the Keck Array. An all-sky, temporally sinusoidal rotation of CMB polarization, equivalent to a time-variable cosmic birefringence, is an observable manifestation of a local axion field and potentially allows a CMB polarimeter to detect axion-like dark matter directly. We describe improvements to the method presented in previous work, and we demonstrate the updated method with an expanded dataset consisting of the 2012-2015 observing seasons. We set limits on the axion-photon coupling constant for mass $m$ in the range $10^{-23}$-$10^{-18}\mathrm{eV}$, which corresponds to oscillation periods on the order of hours to years. Our results are consistent with the background model. For periods between $1$ and $30\mathrm{d}$ ($1.6\times 10^{-21}\le m\le 4.8\times 10^{-20}\mathrm{eV}$), the $95\%$-confidence upper limits on rotation amplitude are approximately constant with a median of $0.27^{\circ }$, which constrains the axion-photon coupling constant to $g_{\varphi \gamma }<(4.5\times 10^{-12}{\mathrm{GeV}}^{-1})m/(10^{-21}\mathrm{eV}$), if axion-like particles constitute all of the dark matter. More than half of the collected BICEP dataset has yet to be analyzed, and several current and future CMB polarimetry experiments can apply the methods presented here to achieve comparable or superior constraints. In the coming years, oscillation measurements can achieve the sensitivity to rule out unexplored regions of the axion parameter space.

    ↳ astro-ph.COhep-exhep-phPRD(2022)·51 citations
34. 34*

    Dark Radiation and the Hagedorn Phase

    Andrew R. Frey🇨🇦 · Ratul Mahanta🇮🇳 · Anshuman Maharana🇮🇳

    We point out that if the sector associated with the Standard Model degrees of freedom entered an open string Hagedorn phase in the early universe while the dark radiation sector was not part of this plasma, then this can lead to low values of the observable $\Delta N_{\text{eff}}$ (number of additional neutrinolike species) from the dark radiation. For explicit analysis, we focus on warped string compactifications with the Standard Model degrees of freedom at the bottom of a warped throat. If the Hubble scale during inflation is above the warped string scale associated with the throat, then the Standard Model sector will enter the Hagedorn phase. In this scenario, bulk axions are no longer dangerous from the point of view of dark radiation. While this article focuses on warped compactifications, the basic idea can be relevant to any scenario where the early universe entered a Hagedorn phase.

    ↳ hep-thastro-ph.COhep-phPRD(2022)·11 citations
35. 35*

    Bayesian approach to long-range correlations and multiplicity fluctuations in nucleus-nucleus collisions

    Kianusch Vahid Yousefnia🇫🇷 · Atharva Kotibhaskar🇮🇳 · Rajeev Bhalerao🇮🇳 · Jean-Yves Ollitrault🇫🇷

    The number of particles detected in a nucleus-nucleus collision strongly depends on the impact parameter of the collision. Therefore, multiplicity fluctuations, as well as rapidity correlations of multiplicities, are dominated by impact parameter fluctuations. We present a method based on Bayesian inference which allows for a robust reconstruction of fluctuations and correlations at fixed impact parameter. We apply the method to ATLAS data on the distribution of charged multiplicity and transverse energy. We argue that multiplicity fluctuations are smaller at large rapidity than around central rapidity. We suggest simple, new analyses, in order to confirm this effect.

    ↳ nucl-thhep-phnucl-exPRC(2022)·19 citations
36. 36*

    Prospects for measuring dark energy with 21 cm intensity mapping experiments

    Peng-Ju Wu🇨🇳 · Xin Zhang🇨🇳

    Using the 21 cm intensity mapping (IM) technique can efficiently perform large-scale neutral hydrogen surveys, and this method has great potential for measuring dark-energy parameters. Some 21 cm IM experiments aiming at measuring dark energy in the redshift range of $0<z<3$ have been proposed and performed, in which the typical ones using single-dish mode include e.g., BINGO, FAST, and SKA1-MID, and those using interferometric mode include e.g., HIRAX, CHIME, and Tianlai. In this work, we make a forecast for these typical 21 cm IM experiments on their capability of measuring parameters of dark energy. We find that the interferometers have great advantages in constraining cosmological parameters. In particular, the Tianlai cylinder array alone can achieve the standard of precision cosmology for the $\Lambda$CDM model (i.e., the precision of parameters is better than 1%). However, for constraining dynamical dark energy, we find that SKA1-MID performs very well. We show that the simulated 21 cm IM data can break the parameter degeneracies inherent in the CMB data, and CMB+SKA1-MID offers $\sigma (w)=0.013$ in the $w$CDM model, and $\sigma (w_0)=0.080$ and $\sigma (w_a)=0.25$ in the CPL model. Compared with CMB+BAO+SN, Tianlai can provide tighter constraints in $\Lambda$CDM and $w$CDM, but looser constraints (tighter than CMB+BAO) in CPL, and the combination CMB+BAO+SN+Tianlai gives $\sigma (w)=0.013$, $\sigma (w_0)=0.055$, and $\sigma (w_a)=0.13$. In addition, it is found that the synergy of FAST ($0<z<0.35$)+SKA1-MID ($0.35<z<0.77$)+Tianlai ($0.77<z<2.55$) offers a very promising survey strategy. Finally, we find that the residual foreground contamination amplitude has a considerable impact on constraint results. We show that in the future 21 cm IM experiments will provide a powerful probe for exploring the nature of dark energy.

    ↳ astro-ph.COgr-qchep-phJCAP(2022)·29 citations
37. 37*

    Standard Model EFTs via On-Shell Methods

    Manuel Accettulli Huber🇬🇧 · Stefano De Angelis🇬🇧

    We present the Standard Model Effective Field Theories (SMEFT) from purely on-shell arguments. Starting from a few basic assumptions such as Poincaré invariance and locality, we classify all the renormalisable and non-renormalisable interactions at the lowest order in the couplings. From these building blocks, we review how locality and unitarity enforce Lie algebra structures to appear in the S-matrix elements together with relations among couplings (and hypercharges). Furthermore, we give a fully on-shell algorithm to compute any higher-point tree-level amplitude (or form factor) in generic EFTs, bypassing BCFW-like recursion relations which are known to be problematic when non-renormalisable interactions are involved. Finally, using known amplitudes techniques we compute the mixing matrix of SMEFT irrelevant interactions up to mass dimension 8, to linear order in the effective interactions.

    ↳ hep-thhep-phJHEP(2021)·86 citations
38. 38*

    A brief account of Steven Weinberg's legacy in ab initio many-body theory

    Christian Drischler🇺🇸 · Scott K. Bogner🇺🇸

    In this contribution to the special issue "Celebrating 30 years of Steven Weinberg's papers on Nuclear Forces from Chiral Lagrangians," we emphasize the important role chiral effective field theory has played in leading nuclear physics into a precision era. To this end, we share our perspective on a few of the recent advances made in ab initio calculations of nuclear structure and nuclear matter observables, as well as Bayesian uncertainty quantification of effective field theory truncation errors.

    ↳ nucl-thhep-phnucl-exFew Body Syst.(2021)·9 citations
39. 39*

    A More Accurate Parameterization based on cosmic Age (MAPAge)

    Lu Huang · Zhiqi Huang · Zhuoyang Li · Huan Zhou

    Recently, several statistically significant tensions between different cosmological datasets have raised doubts about the standard Lambda cold dark matter ($\Lambda$CDM) model. A recent letter~\citet{Huang:2020mub} suggests to use "Parameterization based on cosmic Age" (PAge) to approximate a broad class of beyond-$\Lambda$CDM models, with a typical accuracy $\sim 1\%$ in angular diameter distances at $z\lesssim 10$. In this work, we extend PAge to a More Accurate Parameterization based on cosmic Age (MAPAge) by adding a new degree of freedom ${\eta }_2$. The parameter ${\eta }_2$ describes the difference between physically motivated models and their phenomenological PAge approximations. The accuracy of MAPAge, typically of order $10^{-3}$ in angular diameter distances at $z\lesssim 10$, is significantly better than PAge. We compare PAge and MAPAge with current observational data and forecast data. The conjecture in~\citet{Huang:2020mub}, that PAge approximation is sufficiently good for current observations, is quantitatively confirmed in this work. We also show that the extension from PAge to MAPAge is important for future observations, which typically requires sub-percent accuracy in theoretical predictions.

    ↳ astro-ph.COastro-ph.GAgr-qchep-ph+1Res.Astron.Astrophys.(2021)·17 citations
40. 40*

    Gravitational anomalies, axions and a string-inspired running vacuum model in Cosmology

    Nick E. Mavromatos🇬🇧

    I review a string-inspired cosmological model with gravitational anomalies in its early epochs, which is based on fields from the (bosonic) massless gravitational multiplet of strings, in particular gravitons and Kalb Ramond (KR), string-model independent, axions (the dilaton is assumed constant). I show how condensation of primordial gravitational waves, which are generared at the very early eras immediately after the big bang, can lead to inflation of the so called running vacuum model (RVM) type, without external inflatons. The role of the slow-roll field is played by the KR axion, but it does not drive inflation. The non-linearities in the anomaly terms do. Chiral fermionic matter excitations appear at the end of this RVM inflation, as a result of the decay of the RVM vacuum, and are held responsible for the cancellation of the primordial gravitational anomalies. Chiral anomalies, however, survive in the post-inflationary epochs, and can lead to the generation of a non perturbative mass for the KR axion, which could thus play the role of dark matter in this Universe. As a result of the condensed gravitational anomaly, there is a Lorentz-invariance violating KR axion background, which remains undiluted during the RVM inflation, and can lead to baryogenesis through leptogenesis in the radiation era, in models with sterile right-handed neutrinos. I also discuss the phenomenology of the model in the modern era, paying particular attention to linking it with a version of RVM, called type II RVM, which arguably can alleviate observed tensions in the current-epoch cosmological data.

    ↳ hep-thgr-qchep-ph7 citations
41. 41*

    A forecast of using fast radio burst observations to constrain holographic dark energy

    Xing-Wei Qiu🇨🇳 · Ze-Wei Zhao🇨🇳 · Ling-Feng Wang🇨🇳 · Jing-Fei Zhang🇨🇳 · Xin Zhang🇨🇳

    Recently, about five hundred fast radio bursts (FRBs) detected by CHIME/FRB Project have been reported. The vast amounts of data would make FRBs a promising low-redshift cosmological probe in the forthcoming years, and thus the issue of how many FRBs are needed for precise cosmological parameter estimation in different dark energy models should be detailedly investigated. Different from the usually considered $w(z)$-parameterized models in the literature, in this work we investigate the holographic dark energy (HDE) model and the Ricci dark energy (RDE) model, which originate from the holographic principle of quantum gravity, using the simulated localized FRB data as a cosmological probe for the first time. We show that the Hubble constant $H_0$ can be constrained to about 2% precision in the HDE model with the Macquart relation of FRB by using 10000 accurately-localized FRBs combined with the current CMB data, which is similar to the precision of the SH0ES value. Using 10000 localized FRBs combined with the CMB data can achieve about 6% constraint on the dark-energy parameter $c$ in the HDE model, which is tighter than the current BAO data combined with CMB. We also study the combination of the FRB data and another low-redshift cosmological probe, i.e. gravitational wave (GW) standard siren data, with the purpose of measuring cosmological parameters independent of CMB. Although the parameter degeneracies inherent in FRB and in GW are rather different, we find that more than 10000 FRBs are demanded to effectively improve the constraints in the holographic dark energy models.

    ↳ astro-ph.COgr-qchep-phJCAP(2022)·33 citations
42. 42*

    Measuring the dark matter environments of black hole binaries with gravitational waves

    Adam Coogan🇳🇱 · Gianfranco Bertone🇳🇱 · Daniele Gaggero🇪🇸 · Bradley J. Kavanagh🇪🇸 · David A. Nichols🇺🇸

    Large dark matter overdensities can form around black holes of astrophysical and primordial origin as they form and grow. This "dark dress" inevitably affects the dynamical evolution of binary systems, and induces a dephasing in the gravitational waveform that can be probed with future interferometers. In this paper, we introduce a new analytical model to rapidly compute gravitational waveforms in presence of an evolving dark matter distribution. We then present a Bayesian analysis determining when dressed black hole binaries can be distinguished from GR-in-vacuum ones and how well their parameters can be measured, along with how close they must be to be detectable by the planned Laser Interferometer Space Antenna (LISA). We show that LISA can definitively distinguish dark dresses from standard binaries and characterize the dark matter environments around astrophysical and primordial black holes for a wide range of model parameters. Our approach can be generalized to assess the prospects for detecting, classifying, and characterizing other environmental effects in gravitational wave physics.

    ↳ gr-qcastro-ph.COhep-phPRD(2022)·150 citations
43. 43*

    Improved exclusion limit for light dark matter from $e^{+}{e}^{-}$ annihilation in NA64

    Yu. Andreev🇷🇺 · D. Banerjee🇨🇭 · J. Bernhard🇨🇭 · M. Bondi🇮🇹 · V. Burtsev🇷🇺 · A. Celentano🇮🇹 · N. Charitonidis🇨🇭 · A. Chumakov🇷🇺 · D. Cooke🇬🇧 · P. Crivelli🇨🇭 · E. Depero🇨🇭 · A. Dermenev🇷🇺 and 46 other authors

    The current most stringent constraints for the existence of sub-GeV dark matter coupling to Standard Model via a massive vector boson $A^{\prime }$ were set by the NA64 experiment for the mass region $m_{A^{\prime }}\lesssim 250$ MeV, by analyzing data from the interaction of $2.84\cdot 10^{11}$ 100-GeV electrons with an active thick target and searching for missing-energy events. In this work, by including $A^{\prime }$ production via secondary positron annihilation with atomic electrons, we extend these limits in the $200$-$300$ MeV region by almost an order of magnitude, touching for the first time the dark matter relic density constrained parameter combinations. Our new results demonstrate the power of the resonant annihilation process in missing energy dark-matter searches, paving the road to future dedicated $e^{+}$ beam efforts.

    ↳ hep-exhep-phPRD(2021)·85 citations
44. 44*

    The unbearable lightness of charged gravitini

    Gianguido Dall'Agata🇮🇹 · Maxim Emelin🇮🇹 · Fotis Farakos🇮🇹 · Matteo Morittu🇮🇹

    We prove that charged gravitini cannot have parametrically small or vanishing Lagrangian mass in de Sitter vacua of extended supergravity while respecting the magnetic weak gravity conjecture. This places large classes of de Sitter solutions of gauged supergravity in the swampland, including all known stable solutions of the N=2 theory. We illustrate this result by analyzing a variety of de Sitter critical points of N=2 matter-coupled supergravity that also include new stable de Sitter solutions. Our results provide concrete evidence that (quasi) de Sitter with charged light gravitini should belong to the swampland, which also strongly resonates with the festina lente bound.

    ↳ hep-thgr-qchep-phJHEP(2021)·35 citations
45. 45*

    On the Search for Low $W_0$

    Igor Broeckel🇮🇹 · Michele Cicoli🇮🇹 · Anshuman Maharana🇮🇳 · Kajal Singh🇮🇳 · Kuver Sinha🇺🇸

    The magnitude of the vacuum expectation value of the Gukov-Vafa-Witten superpotential $|W_0|$ plays a central role in the phenomenology of type IIB flux compactifications. Recent analytical constructions have shown that perturbatively flat vacua can be used to obtain very low values of $|W_0|$. We present systematic algorithms to carry out exhaustive numerical searches for such vacua. We also analyse them in the statistical context, as part of the entire ensemble of type IIB flux vacua at low $|W_0|$. Our preliminary analysis indicates that these perturbatively flat vacua are statistically sparse in the whole set of vacua at low $|W_0|$ as calculated by Denef and Douglas. Two-moduli examples are used to illustrate these more general findings in specific settings. We find that these simple cases are good examples for existence proofs but they do not feature a large statistical tuning freedom for phenomenological applications.

    ↳ hep-thhep-phFortsch.Phys.(2022)·30 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.