Fri·Apr 1, 2022Friday·April 1, 2022

1. 01*

   Speed of Sound for Hadronic and Quark Phases in a Magnetic Field

   E. J. Ferrer🇺🇸 · A. Hackebill🇺🇸

   In this paper we calculate the speed of sound for three phases that may exist inside a magnetized hybrid neutron star at different density regions: A hadronic phase at low densities, quark-matter in the magnetic dual chiral density wave (MDCDW) phase at intermediate densities and a free-quark phase modeled by the MIT bag model at higher densities. It is found that the speed of sound exhibits a non-monotonic behavior, that goes from values smaller than the conformal limit ($c_s^2<1/3$) in the hadronic phase, to peak ($c_s^2>1/3$) in the MDCDW phase, to finally reach the conformal limit ($c_s^2\sim 1/3$) at higher densities for quarks in the MIT bag model. Also, the anisotropic speed of sound in the presence of a magnetic field is derived from first principles. This is a consequence of the anisotropy in the system's pressures produced by the breaking of the rotational symmetry in the presence of a magnetic field. The role played by the lowest Landau level contribution in affecting the speed of sound in the magnetized phases is discussed.

   hep-phnucl-thNPA(2023)·22 citations
2. 02*

   $\mathcal{O}({\alpha }_s^3)$ calculations for the inclusive determination of $|V_{cb}|$

   Kay Schönwald🇩🇪

   For the determination of the Cabbibo-Kobayashi-Maskawa matrix element $|V_{cb}|$ from inclusive data a precise knowledge of the semileptonic $b\to c$ decay rate is necessary. Since this observable has a bad convergence behavior when the heavy quark masses are expressed in the on-shell or $\overline{\text{MS}}$ scheme the latest determinations have been obtained in the so called kinetic mass scheme. The relation between the different schemes needs to be known to high precision as well. In this proceedings we present our recent calculations which push the precision of both ingredients to $\mathcal{O}({\alpha }_s^3)$. The results can be used to improve the inclusive determination of $|V_{cb}|$.

   hep-phPoS(2023)·0 citations
3. 03*

   Substructure of Multiquark Hadrons (Snowmass 2021 White Paper)

   Nora Brambilla🇩🇪 · Hua-Xing Chen🇨🇳 · Angelo Esposito🇺🇸 · Jacopo Ferretti🇫🇮 · Anthony Francis🇹🇼 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Atsushi Hosaka🇯🇵 · Robert L. Jaffe🇺🇸 · Marek Karliner🇮🇱 · Richard Lebed🇺🇸 · Randy Lewis🇨🇦 and 18 other authors

   In recent years there has been a rapidly growing body of experimental evidence for existence of exotic, multiquark hadrons, i.e. mesons which contain additional quarks, beyond the usual quark-antiquark pair and baryons which consist of more than three quarks. In all cases with robust evidence they contain at least one heavy quark Q=c or b, the majority including two heavy quarks. Two key theoretical questions have been triggered by these discoveries: (a) how are quarks organized inside these multiquark states -- as compact objects with all quarks within one confinement volume, interacting via color forces, perhaps with an important role played by diquarks, or as deuteron-like hadronic molecules, bound by light-meson exchange? (b) what other multiquark states should we expect? The two questions are tightly intertwined. Each of the interpretations provides a natural explanation of parts of the data, but neither explains all of the data. It is quite possible that both kinds of structures appear in Nature. It may also be the case that certain states are superpositions of the compact and molecular configurations. This Whitepaper brings together contributions from many leading practitioners in the field, representing a wide spectrum of theoretical interpretations. We discuss the importance of future experimental and phenomenological work, which will lead to better understandingof multiquark phenomena in QCD.

   hep-ph32 citations
4. 04*

   From well-known tensor mesons to yet unknown axial-tensor mesons

   Shahriyar Jafarzade🇵🇱 · Arthur Vereijken🇵🇱 · Milena Piotrowska🇵🇱 · Francesco Giacosa🇵🇱

   While the ground-state tensor ($J^{PC}=2^{++}$) mesons $a_2(1320)$, $K_2^{\ast }(1430)$, $f_2(1270)$, and $f_2^{\prime }(1525)$ are well known experimentally and form an almost ideal nonet of quark-antiquark states, their chiral partners, the ground-states axial-tensor ($J^{PC}=2^{--}$) mesons are poorly settled: only the kaonic member $K_2(1820)$ of the nonet has been experimentally found, whereas the isovector state ${\rho }_2$ and two isoscalar states ${\omega }_2$ and ${\varphi }_2$ are still missing. Here, we study masses, strong, and radiative decays of tensor and axial-tensor mesons within a chiral model that links them: the established tensor mesons are used to test the model and to determine its parameters, and subsequently various predictions for their chiral partners, the axial-tensor mesons, are obtained. The results are compared to current lattice QCD outcomes as well as to other theoretical approaches and show that the ground-state axial-tensor mesons are expected to be quite broad, the vector-pseudoscalar mode being the most prominent decay mode followed by the tensor-pseudoscalar one. Nonetheless, their experimental finding seems to be possible in ongoing and/or future experiments.

   hep-phPRD(2022)·20 citations
5. 05*

   Universal location of Yang-Lee edge singularity for a one-component field theory in $1\le d\le 4$

   Fabian Rennecke🇩🇪 · Vladimir V. Skokov🇺🇸

   We determine the universal location of the Yang-Lee edge singularity in the entire relevant domain of spatial dimensions $1\le d\le 4$ for the Ising universality class. To that end, we present analytical results for $d=1,2,4$ and near four dimensions. For $d=3$ and a set of fractional dimensions, we perform numerical calculations using a systematic Functional Renormalization Group approach.

   hep-phcond-mat.stat-mechAnnals Phys.(2022)·37 citations
6. 06*

   Low Energy Protons as Probes of Hadronization Dynamics

   Carolina M. Robles Gajardo🇨🇱 · Alberto Accardi🇺🇸 · Mark D. Baker🇺🇸 · William K. Brooks🇨🇱 · Raphaël Dupré🇫🇷 · Mathieu Ehrhart🇫🇷 · Jorge A. López🇩🇪 · Zhoudunming Tu🇺🇸

   Energetic quarks liberated from hadrons in nuclear deep-inelastic scattering propagate through the nuclear medium, interacting with it via several processes. These include quark energy loss and nuclear interactions of forming hadrons. One manifestation of these interactions is the enhanced emission of low-energy charged particles, referred to as grey tracks. We use the theoretical components of the BeAGLE event generator to interpret grey track signatures of parton transport and hadron formation by comparing its predictions to E665 data. We extend the base version of BeAGLE by adding four different options for describing parton energy loss. The E665 data we used consists of multiplicity ratios for fixed-target scattering of 490 GeV muons on Xe normalized to deuterium as a function of the number of grey tracks. We compare multiplicity ratios for E665 grey tracks to the predictions of BeAGLE, varying the options and parameters to determine which physics phenomena can be identified by these data. We find that grey tracks are unaffected by modifications of the forward production. Thus their production must be dominated by interactions with hadrons in the backward region. This offers the advantage that selecting certain particles in the forward region is unlikely to bias a centrality selection. We see a strong correlation between the number of grey tracks and the in-medium path length. Our energy loss model does not reproduce the suppression observed in the projectile region. We see an underprediction of the proton production rate in backward kinematics, suggesting that a stronger source of interaction with the nuclear medium is needed for accurate modeling. These results lay an important foundation for future spectator tagging studies at both Jefferson Lab and at the Electron-Ion Collider, where neutron and proton grey track studies will be feasible down to very small momenta.

   hep-phhep-exnucl-exPRC(2022)·5 citations
7. 07*

   Probing highly collimated photon-jets with deep learning

   Xiaocong Ai🇩🇪 · Shih-Chieh Hsu🇺🇸 · Ke Li🇺🇸 · Chih-Ting Lu🇰🇷

   Many extensions of the standard model (SM) predict the existence of axion-like particles and/or dark Higgs in the sub-GeV scale. Two new sub-GeV particles, a scalar and a pseudoscalar, produced through the Higgs boson exotic decays, are investigated. The decay signatures of these two new particles with highly collimated photons in the final states are discriminated from the ones of SM backgrounds using the Convolutional Neural Networks and Boosted Decision Trees techniques. The sensitivities of searching for such new physics signatures at the Large Hadron Collider are obtained.

   hep-phJ.Phys.Conf.Ser.(2023)·6 citations
8. 08*

   Non-diagonal contributions to $Z\gamma V^{\ast }$ vertex, polarizations and bounds on $Z\overline{t}q$ couplings

   A.I. Hernández-Juárez🇲🇽 · G. Tavares-Velasco🇲🇽 · R. Gaitán🇲🇽

   We study the flavor-changing neutral current contributions to the trilinear neutral gauge boson couplings $Z\gamma V^{\ast }$ ($V=Z$, $\gamma$) at the one-loop level. Only the $CP$-conserving form factor $h_3^Z$ is induced, with the relevant contributions arising from top quark couplings. To our numerical analysis, constraints on the $Z\overline{t}q$ ($q=c$, $u$) couplings are obtained from current LHC data, leading to bounds of $|g_{\text{V}}^{tu}|\text{,}|g_{\text{A}}^{tu}|⩽0.007$ and $|g_{\text{V}}^{tc}|\text{,}|g_{\text{A}}^{tc}|⩽0.0095$ for the vector and axial couplings. The new contributions to the $h_3^Z$ form factor are of order $10^{-7}$. Furthermore, we analyze the polarized partial decay widths of the $V^{\ast }\to Z\gamma$ process, and a new type of left-right asymmetry is also discussed. We find that in the presence of new physics, the polarized $\Gamma (V^{\ast }\to Z\gamma )$ exhibits significant deviations from the SM prediction, resulting in a non-zero asymmetry.

   hep-phInt.J.Mod.Phys.A(2025)·14 citations
9. 09*

   PV-Reduction of Sunset Topology with Auxiliary Vector

   Bo Feng🇨🇳 · Tingfei Li🇨🇳

   Passarino-Veltman (PV) reduction method has been proved to be very useful for the computation of general one-loop integrals. However, not much progress has been made when applying to higher loops. Recently, we have improved the PV-reduction method by introducing an auxiliary vector. In this paper, we apply our new method to the simplest two-loop integrals, i.e., the sunset topology. We show how to use differential operators to establish algebraic recursion relations for reduction coefficients. Our algorithm can be easily applied to the reduction of integrals with arbitrary high-rank tensor structures. We demonstrate the efficiency of our algorithm by computing the reduction with the total tensor rank up to four.

   hep-phCommun.Theor.Phys.(2022)·17 citations
10. 10*

    A toy model for "elementariness"

    Peter C. Bruns🇨🇿

    Motivated by recent efforts to analyze corrections to Weinberg's relations for the scattering length and effective range in the presence of a near-threshold bound state, we play around with an instructive toy model for non-relativistic scattering in a central potential. The model allows to interpolate between bound-state configurations of high "compositeness", where the wave function is spread over a wide region beyond the range of the interaction, and compact configurations of high "elementariness", where the wave function is confined to a small region around the center of the potential.

    hep-ph6 citations
11. 11*

    Exclusive production of light vector mesons at next-to-leading order in the dipole picture

    Heikki Mäntysaari🇫🇮 · Jani Penttala🇫🇮

    Exclusive production of light vector mesons in deep inelastic scattering is calculated at next-to-leading order in the dipole picture in the limit of high photon virtuality. The resulting expression is free of any divergences and suitable for numerical evaluations. The higher-order corrections are found to be numerically important, but they can be mostly captured by the nonperturbative fit parameters describing the initial condition for the small-$x$ evolution of the dipole scattering amplitude. The vector meson production cross section is shown to depend only weakly on the meson distribution amplitude and the factorization scale. We also present phenomenological comparisons of our result to the existing exclusive $\varphi$ and $\rho$ production data from HERA and find an excellent agreement at high virtualities.

    hep-phnucl-thPRD(2022)·47 citations
12. 12*

    Accessing pion GPDs through the Sullivan process: is it feasible?

    Jose Manuel Morgado Chávez🇪🇸 · Valerio Bertone🇫🇷 · Maxime Defurne🇫🇷 · Feliciano de Soto🇪🇸 · Cédric Mezrag🇫🇷 · Hervé Moutarde🇫🇷 · José Rodríguez-Quintero🇪🇸 · Jorge Segovia🇪🇸

    Describing hadronic structure is one of the most intriguing problems in physics. In this respect, generalized parton distributions (GPDs) constitute an outstanding tool, allowing to draw "three dimensional pictures" of hadron's inside. Starting from contemporary models for pion's GPDs fulfilling all constraints imposed by QCD, we compute Compton form factors (CFFs) of pions subjected to deeply virtual Compton scattering. We show the behaviour of CFFs to be gluon-dominated at EIC's kinematics. Finally we evaluate lepton-beam-spin asymmetries in the Sullivan process, demonstrating the existence of such and thus triggering optimism about the possibility of probing pion's 3D structure at electron-ion colliders.

    hep-phnucl-thRev.Mex.Fis.Suppl.(2022)·4 citations
13. 13*

    Constraining extended scalar sectors at current and future colliders

    Tania Robens🇭🇷

    In this proceeding, I summarize results on various new physics extensions of the Standard Model, for models with and without dark matter candidates. I discuss current constraints as well as rates and discovery prospects at future colliders.

    hep-phPoS(2022)·5 citations
14. 14*

    Analytic Map of Three-Channel S Matrix -Generalized Uniformization and Mittag-Leffler Expansion-

    Wren A. Yamada🇯🇵 · Osamu Morimatsu🇯🇵 · Toru Sato🇯🇵

    We explore the analytic structure of the three-channel $S$ matrix by generalizing uniformization and making a single-valued map for the three-channel $S$ matrix. First, by means of the inverse Jacobi's elliptic function we construct a transformation from eight Riemann sheets of the center-of-mass energy squared complex plane onto a torus, on which the three-channel $S$ matrix is represented single-valued. Secondly, we show that the Mittag-Leffler expansion, a pole expansion, of the three-channel scattering amplitude includes not only topologically trivial but also nontrivial contributions and is given by the Weierstrass zeta function. Finally, we examine the obtained formula in the context of a simple three-channel model. Taking a simple non-relativistic effective field theory with contact interaction for the $S=-2$, $I=0$, $J^P=0^{+}$, $\Lambda \Lambda -N\Xi -\Sigma \Sigma$ coupled-channel scattering, we demonstrate that the scattering amplitude as a function of the uniformization variable is, in fact, given by the Mittag-Leffler expansion with the Weierstrass zeta function and that it is dominated by contributions from neighboring poles.

    hep-phnucl-thPRL(2022)·9 citations
15. 15*

    The possible assignments of the scalar $K_0^{\ast }(1950)$ and $K_0^{\ast }(2130)$ within the ${}^3{P}_0$ model

    Tian-Ge Li🇨🇳 · Zhuo Gao🇨🇳 · Guan-Ying Wang🇨🇳 · De-Min Li🇨🇳 · En Wang🇨🇳 · Jingya Zhu🇨🇳

    We have evaluated the strong decays of the $K_0^{\ast }(1950)$ and $K_0^{\ast }(2130)$ within the ${}^3{P}_0$ model, by employing the meson wave functions from the relativized quark model. By comparing with the experimental measurements, the $K_0^{\ast }(2130)$ could be assigned as $K_0^{\ast }(3^3{P}_0)$, while the $K_0^{\ast }(1950)$ seems like an exotic state, because its width can not be reasonably reproduced within the ${}^3{P}_0$ model. We also predict that the $K_0^{\ast }(2^3{P}_0)$ state has a mass of about $1811$ MeV and a width of about $656$ MeV, while the $K_0^{\ast }(4^3{P}_0)$ state has a mass of about $2404$ MeV and a width of about $180$ MeV.

    hep-phPRD(2022)·6 citations
16. 16*

    Electron scattering of light new particles from evaporating primordial black holes

    Roberta Calabrese🇮🇹 · Marco Chianese🇮🇹 · Damiano F.G. Fiorillo🇩🇰 · Ninetta Saviano🇮🇹

    Primordial black holes are a possible component of dark matter, and a most promising way of investigating them is through the product of their Hawking evaporation. As a result of this process, any species lighter than the Hawking temperature is emitted, including possible new particles beyond the Standard Model. These can then be detected in lab-based experiments via their interaction with the Standard Model particles. In a previous work, we have first proposed and studied this scenario in the presence of an interaction between the light new species and nucleons. Here we extend this discussion to include the case of interaction with electrons. We show that the simultaneous presence of primordial black holes and species lighter than about $100$ MeV can be constrained by the measurements of direct detection experiments, such as XENON1T, and water Cherenkov neutrino detectors, such as Super-Kamiokande. Our results provide a complementary and alternative way of investigation with respect to cosmological and collider searches.

    hep-phPRD(2022)·28 citations
17. 17*

    Triangle singularities in the $T_{cc}^{+}\to D^{\ast +}{D}^0\to {\pi }^{+}{D}^0{D}^0$ decay width

    N.N. Achasov🇷🇺 · G.N. Shestakov🇷🇺

    The values of the masses of the particles involved in the decay of $T_{cc}^{+}\to D^{\ast +}{D}^0\to {\pi }^{+}{D}^0{D}^0$ suggest that due to the final state interactions in the transition vertex $T_{cc}^{+}\to D^{\ast +}{D}^0$ there may be triangle logarithmic singularities. We discuss their possible role and show that the tree approximation for calculating the decay widths $T_{cc}^{+}\to (D^{\ast +}{D}^0+D^{\ast 0}{D}^{+})\to {\pi }^{+}{D}^0{D}^0$, ${\pi }^0{D}^0{D}^{+}$, $\gamma D^0{D}^{+}$ is quite sufficient at the current level of measurement accuracy.

    hep-phhep-exnucl-exnucl-thPRD(2022)·20 citations
18. 18*

    Searching and identifying leptoquarks through low-energy polarized scattering processes $e^{-}p\to e^{-}{\Lambda }_c$

    Li-Fen Lai🇨🇳 · Xin-Qiang Li🇨🇳 · Xin-Shuai Yan🇨🇳 · Ya-Dong Yang🇨🇳

    We investigate the potential for searching and identifying the leptoquark (LQ) effects in the charm sector through the low-energy polarized scattering processes ${\vec{e}}^{-}p\to e^{-}{\Lambda }_c$, $e^{-}\vec{p}\to e^{-}{\Lambda }_c$, and ${\vec{e}}^{-}\vec{p}\to e^{-}{\Lambda }_c$. Considering only the longitudinally polarized processes, we show that the different LQ models can be disentangled from each other by measuring the four spin asymmetries, $A_L^e$, $A_L^p$, $A_{L3}^{ep}$, and $A_{L6}^{ep}$, constructed in terms of the polarized cross sections. Although it is challenging to accomplish the same goal with transversely polarized processes, we find that investing them in future experiments is especially beneficial, since they can directly probe into the imaginary part of the Wilson coefficients in the general low-energy effective Lagrangian. With our properly designed experimental setups, it is also demonstrated that promising event rates can be expected for all these processes and, even in the worst-case scenario -- no LQ signals are observed at all, they can still provide a competitive potential for constraining the new physics, compared with those from the conventional charmed-hadron weak decays and the high-$p_T$ dilepton invariant mass tails at high-energy colliders.

    hep-phhep-exPRD(2022)·4 citations
19. 19*

    Light-by-Light Scattering at Future $e^{+}{e}^{-}$ Colliders

    John Ellis (King's College London, Nat. Inst. Chem. Phys. and Biophys., Tallinn and CERN)🇬🇧 · Nick E. Mavromatos (Natl. Tech. U. Athens and King's College London)🇬🇧 · Philipp Roloff (CERN)🇨🇭 · Tevong You (CERN, DAMTP-U. Cambridge)🇨🇭

    We study the sensitivity of possible CLIC and FCC-ee measurements of light-by-light scattering to old and new physics, including the Heisenberg-Euler Lagrangian in the Standard Model with possible contributions from loops of additional charged particles or magnetic monopoles, the Born-Infeld extension of QED, and effective dimension-8 operators involving four electromagnetic field strengths as could appear in the Standard Model Effective Field Theory. We find that FCC-ee measurements at 365 GeV and CLIC measurements at 350 GeV would be sensitive to new physics scales of half a TeV in the dimension-8 operator coefficients, and that CLIC measurements at 1.4 TeV or 3 TeV would be sensitive to new physics scales {$\sim 2$ TeV or 5 TeV} at 95\% CL, corresponding to probing loops of new particles with masses up to $\sim 3.7$ TeV {for large charges and/or multiple species}. Within Born-Infeld theory, the $95\%$ CL sensitivities would range from $\sim 300$ GeV to 1.3 or 2.8 TeV for the high-energy CLIC options. Measurements of light-by-light scattering would not exclude monopole production at FCC-hh, except in the context of Born-Infeld theory.

    hep-phhep-exhep-thEPJC(2022)·47 citations
20. 20*

    Light Dark Matter Detection and Neutrino Floor: Role of Anomalous $(g-2{)}_{\mu }$

    Kuldeep Deka🇮🇳 · Soumya Sadhukhan🇮🇳 · Manvinder Pal Singh🇮🇳

    In this work, we explore the impact of dark matter (DM) relic density and direct detection constraints on a GeV scale DM in the context of recent anomalous muon magnetic moment $(g-2{)}_{\mu }$ measurement; a $5.1\sigma$ discrepancy with the SM. In $U(1{)}_{L_{\mu }-L_{\tau }}$ scenario the additional $Z^{\prime }$ boson modifies the $(g-2{)}_{\mu }$ value readily explaining the discrepancy, which restricts the $Z^{\prime }$ mass in the range of $20-200$~MeV. Bounds imposed on the $Z^{\prime }$ mass along with the gauge coupling, limit possible enhancement of the neutrino floor in an $U(1{)}_{L_{\mu }-L_{\tau }}$ model. Neutrino floor is enhanced for a lighter $Z^{\prime }$ inside the $(g-2{)}_{\mu }$ allowed parameter space, whereas for a heavier $Z^{\prime }$, enhancement is less significant. The $(g-2{)}_{\mu }$ constraint for the GeV scale Fermionic DM makes s-channel resonant annihilation insignificant, placing emphasis on a t-channel reliance to create the observed DM relic. Although a t-channel annihilation aided by relatively large couplings can explain the measured relic density, it increases the direct detection cross-section of the GeV DM. Consequently, super-GeV (with mass $1-10$~GeV) DM almost gets ruled out except for a small parameter region with heavier $Z^{\prime }$, whereas sub-GeV (with mass $0.1-1$~GeV) DM detection possibility remains bright with more detection possibility for heavier $Z^{\prime }$. In our analysis, we have discovered that direct detection constraints have a greater impact on the GeV DM compared to indirect detection measurements.

    hep-ph5 citations
21. 21*

    Isovector helicity quark quasi-distributions inside a large Nc nucleon

    Hyeon-Dong Son🇰🇷

    In this letter, we report the results for the isovector polarized quark quasi-distribution functions $\Delta u(x,v)-\Delta d(x,v)$ in the large $N_c$, calculated within the chiral quark-soliton model. It is shown that the polarized quark quasi-distributions present good convergence to the light-cone PDFs in the limit of the nucleon boost momentum $P_N\to \infty$ (or the velocity $v\to 1$), compared to the case of the unpolarized isosinglet distributions.

    hep-phhep-latPLB(2023)·6 citations
22. 22*

    Vector boson pair production at one loop: analytic results for the process $q\bar{q}\ell \bar{\ell }{\ell }^{\prime }{\bar{\ell }}^{\prime }g$

    John M. Campbell🇺🇸 · Giuseppe De Laurentis🇩🇪 · R. Keith Ellis🇬🇧

    We present compact analytic results for the one-loop amplitude for the process $0\to q\bar{q}\ell \bar{\ell }{\ell }^{\prime }{\bar{\ell }}^{\prime }g$, relevant for both the production of a pair of $Z$ and $W$-bosons in association with a jet. We focus on the gauge-invariant contribution mediated by a loop of quarks. We explicitly include all effects of the loop-quark mass $m$, appropriate for the production of a pair of $Z$-bosons. In the limit $m\to 0$, our results are also applicable to the production of $W$-boson pairs, mediated by a loop of massless quarks. Implemented in a numerical code, the results are fast. The calculation uses novel advancements in spinor-helicity simplification techniques, for the first time applied beyond five-point massless kinematics. We make use of primary decompositions from algebraic-geometry, which now involve non-radical ideals, and $p$-adic numbers from number theory. We show how to infer whether numerator polynomials belong to symbolic powers of non-radical ideals through numerical evaluations.

    hep-phhep-thJHEP(2022)·15 citations
23. 23*

    The collider landscape: which collider for establishing the SM instability?

    Roberto Franceschini · Alessandro Strumia · Andrea Wulzer

    Capabilities of future colliders are usually discussed assuming specific hypothetical new physics. We consider the opposite possibility: that no new physics is accessible, and we want to learn if the unnatural Standard Model is part of a vast landscape. We argue that a main step in this direction would be establishing the possible instability scale of the Higgs potential. This primarily needs reducing the uncertainty on the strong coupling and on the top quark mass. We show that the top quark mass can be measured well enough via a $t\bar{t}$ threshold scan with low $10^{33}{\mathrm{cm}}^{-2}{\sec }^{-1}$ luminosity, that seems achievable at a `small' $e^{+}{e}^{-}$ collider in the LEP tunnel, or at the first low-energy stage of a muon collider.

    hep-phhep-exhep-thJHEP(2022)·14 citations
24. 24*

    Two-loop mixed QCD-EW corrections to $q\overline{q}\to Hg$, $qg\to Hq$, and $\overline{q}g\to H\overline{q}$

    Marco Bonetti🇩🇪 · Erik Panzer🇬🇧 · Lorenzo Tancredi🇩🇪

    We compute the two-loop mixed QCD-Electroweak corrections to $q\overline{q}\to Hg$ and its crossed channels $qg\to Hq$, $\overline{q}g\to H\overline{q}$, limiting ourselves to the contribution of light virtual quarks. We compute the independent helicity amplitudes as well as the form factors for this process, expressing them in terms of hyperlogarithms with algebraic arguments. The Feynman integrals are computed by direct integration over Feynman parameters and the results are expressed in terms of a basis of rational prefactors.

    hep-phJHEP(2022)·23 citations
25. 25*

    Anomaly-free axion dark matter in three Higgs doublet model and its phenomenological implications

    Kodai Sakurai🇯🇵 · Fuminobu Takahashi🇯🇵

    We study phenomenological implications of an axion that arises as a pseudo Nambu-Goldstone boson due to the spontaneous breaking of anomaly-free global flavor symmetry. One interesting possibility for such anomaly-free axion to explain dark matter (DM) is when it has a mass of order keV and an intermediate scale decay constant, since it can be explored through direct search experiments, X-ray observations, various stellar cooling processes, and the misalignment mechanism naturally explains the DM abundance. As a concrete renormalizable model of such axion, we consider an extended Higgs sector with global flavor symmetry, which consists of three Higgs doublet fields and three singlet Higgs fields with $U(1{)}_{\mathrm{B}-\mathrm{L}}$ charges. We identify viable parameter regions that satisfy theoretical bounds on the Higgs potential and various experimental limits on this model, and evaluate the mass spectra of the axion and extra Higgs bosons. We find that even an anomaly-free axion can generally couple to photons through mixing with CP-odd Higgs, and that its strength depends on the vacuum expectation values of the Higgs doublets as well as the axion mass. As a result, the ratios of the vacuum expectation values of the Higgs doublets are tightly constrained to satisfy the X-ray constraints. We show the favored parameter region where axion DM explains the XENON1T excess. We also demonstrate that the axion-electron coupling is correlated with the extra Higgs boson masses and mixing angles for CP-even Higgs bosons. Thus, if the axion is detected in future observations, the extra Higgs boson masses and the coupling of the standard model-like Higgs boson with the weak gauge bosons are restricted. This is a good example of the synergy between searches for the axion DM and the BSM around the electroweak scale.

    hep-phJHEP(2022)·11 citations
26. 26*

    More is Different: Non-Minimal Dark Sectors and their Implications for Particle Physics, Astrophysics, and Cosmology -- 13 Take-Away Lessons for Snowmass 2021

    Keith R. Dienes🇺🇸 · Brooks Thomas🇺🇸

    The phrase "more is different" is often used to refer to the new, unexpected collective phenomena that can arise when the number of states in a given system is large. In this contribution to the Snowmass 2021 Study, we describe 13 unexpected collective phenomena that can arise when the dark sector contains a large number of states, contrary to the usual assumptions. These 13 take-away lessons stretch across all of the domains of relevance for dark-matter physics, including collider signatures, direct-detection signatures, indirect-detection signatures, new perspectives on dark-matter complementarity, and even unexpected astrophysical and cosmological phenomena that transcend those normally associated with single-component dark-matter scenarios. These lessons -- and the phenomena on which they are based -- thereby illustrate the need to maintain a broad perspective when contemplating the possible signatures and theoretical possibilities associated with non-minimal dark sectors.

    hep-phastro-ph.CO16 citations
27. 27*

    Electroweak monopoles and their stability

    Romain Gervalle🇫🇷 · Mikhail S. Volkov🇫🇷

    We apply a generalized field ansatz to describe the spherically symmetric sector of classical solutions of the electroweak theory. This sector contains Abelian magnetic monopoles labeled by their magnetic charge $n=\pm 1,\pm 2,\dots$, the non-Abelian monopole for $n=\pm 2$ found previously by Cho and Maison (CM), and also the electric oscillating solutions. All magnetic monopoles have infinite energy. We analyze their perturbative stability and use the method of complex spacetime tetrad to separate variables and reduce the perturbation equations to multi-channel Schroedinger-type eigenvalue problems. The spectra of perturbations around the CM monopole do not contain negative modes hence this solution is stable. The $n=\pm 1$ Abelian monopole is also stable, but all monopoles with $|n|\ge 2$ are unstable with respect to perturbations with angular momentum $j=|n|/2-1$. The Abelian $|n|=2$ monopole is unstable only within the $j=0$ sector whereas the CM monopole also has $|n|=2$ and belongs to the same sector, hence it may be viewed as a stable remnant of the decay of the Abelian monopole. One may similarly conjecture that stable remnants exist also for monopoles with $|n|>2$, hence the CM monopole may be just the first member of a sequence of non-Abelian monopoles with higher magnetic charges. Only the CM monopole is spherically symmetric while all non-Abelian monopoles with $|n|>2$ are not rotationally invariant.

    ↳ hep-thhep-phNPB(2022)·22 citations
28. 28*

    Optimizing Observables with Machine Learning for Better Unfolding

    Miguel Arratia🇺🇸 · Daniel Britzger🇩🇪 · Owen Long🇺🇸 · Benjamin Nachman🇺🇸

    Most measurements in particle and nuclear physics use matrix-based unfolding algorithms to correct for detector effects. In nearly all cases, the observable is defined analogously at the particle and detector level. We point out that while the particle-level observable needs to be physically motivated to link with theory, the detector-level need not be and can be optimized. We show that using deep learning to define detector-level observables has the capability to improve the measurement when combined with standard unfolding methods.

    ↳ hep-exhep-phJINST(2022)·15 citations
29. 29*

    Observable vacuum energy is finite in expanding space

    Csaba Balazs🇦🇺

    In this work I reason that in expanding space only those quantum modes contribute to the measured vacuum energy that do not transcend the observable volume. Since all quantised field modes have various observable consequences, when a gravitational horizon causally confines an observer to a finite volume quantised modes should be restricted to the observable patch to remain consistent with gravity. Within the observable patch of Friedmann-Lemaitre-Robertson-Walker (FLRW) space the vacuum expectation value of the energy-momentum tensor can be expressed as a sum over discrete field modes. Friedmann's first equation provides a straightforward ultraviolet cut-off allowing only a finite number of modes in the sum. The finite volume acts as an infrared regulator and the calculation of the vacuum energy density is tractable without regularisation and renormalisation. To test the validity of this idea I quantise a scalar field on an FLRW background and calculate its vacuum energy density in the vacuum dominated, conformal, holographic limit. In this limit I show that the quantum vacuum energy density scales with the square of the Hubble parameter, consistently with gravity. In this example quantum vacuum expands space while the horizon of the expanding space limits the energy density of the vacuum to the observed value.

    ↳ gr-qcastro-ph.COhep-phhep-th3 citations
30. 30*

    Snowmass White Paper: prospects for measurements of the bottom quark mass

    Javier Aparisi🇪🇸 · Juan Fuster🇪🇸 · Andre Hoang🇦🇹 · Adrian Irles🇪🇸 · Christopher Lepenik🇦🇹 · Vicent Mateu🇪🇸 · German Rodrigo🇪🇸 · Michael Spira🇨🇭 · Seidai Tairafune🇯🇵 · Junping Tian🇯🇵 · Marcel Vos🇪🇸 · Hitoshi Yamamoto🇪🇸 · Ryo Yonamine🇯🇵

    In this white paper for the Snowmass '21 community planning exercise we provide quantitative prospects for bottom quark mass measurements in high-energy collisions at future colliders that can provide a precise test of the scale evolution, or "running" of quark masses predicted by QCD.

    ↳ hep-exhep-ph10 citations
31. 31*

    Assessing the ultracentral flow puzzle in hydrodynamic modeling of heavy-ion collisions

    A. V. Giannini🇧🇷 · M. N. Ferreira🇧🇷 · M. Hippert🇺🇸 · D. D. Chinellato🇧🇷 · G. S. Denicol🇧🇷 · M. Luzum🇧🇷 · J. Noronha🇺🇸 · T. Nunes da Silva🇧🇷 · J. Takahashi🇧🇷

    An outstanding problem in heavy-ion collisions is the inability for models to accurately describe ultra-central experimental flow data, despite that being precisely the regime where a hydrodynamic description should be most applicable. We reassess the status of this puzzle by computing the flow in ultra-central collisions obtained from multiple recent Bayesian models that were tuned to various observables in different collision systems at typical centralities. While central data can now be described with better accuracy than in previous calculations, tension with experimental observation remains and worsens as one goes to ultra-central collisions. Tuning the model parameters cannot remove this tension without destroying the fit at other centralities. As such, new elements are likely needed in the standard modeling of heavy-ion collisions.

    ↳ nucl-thhep-phPRC(2023)·21 citations
32. 32*

    Primordial Stochastic Gravitational Wave Background Anisotropies: in-in Formalization and Applications

    Ema Dimastrogiovanni🇳🇱 · Matteo Fasiello🇪🇸 · Lucas Pinol🇪🇸

    Primordial non-Gaussianities of the scalar(tensor)-tensor-tensor type supporting a non-trivial squeezed component are known to induce anisotropies in the stochastic gravitational wave background. We derive the explicit form of such anisotropies by making use, for the first time in this context, of the in-in formalism for cosmological correlation functions. After illustrating the general method and using it for the minimal single-field slow-roll case, we apply it to multi-field models, providing both a tree-level and a one-loop example. First, we make contact with previous results on anisotropies due to the presence of an extra spin-2 field during inflation. Secondly, we calculate the 1-loop scalar-tensor-tensor three-point function in the context of so-called supersolid inflation. The corresponding gravitational wave anisotropy is induced atop a gravitational signal that may be sufficiently large for detection.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2022)·21 citations
33. 33*

    Cosmological Neutrinos

    Floyd W. Stecker🇺🇸

    Within the context of hot big-bang cosmology, a cosmic background of presently low energy neutrinos is predicted to exist in concert with the photons of the cosmic background radiation. The number density of the cosmological neutrinos is of the same order as that of the photons of the cosmic background radiation. That makes neutrinos the second most abundant particle species in the universe. In the early universe, when these neutrinos were highly relativistic, their effects in determining the ultimate structure and evolution of the universe were significant.

    ↳ astro-ph.COastro-ph.HEhep-ph0 citations
34. 34*

    Gravitational Wave Signals from Finite Size Effects in Spinning Binary Inspirals Including Parity Violating Constituents

    Beka Modrekiladze🇺🇸

    We generalize the world line EFT formalism to account for parity violating finite size effects. Results are presented for potentials and radiating moments of a binary inspiral for the parity conserving sector, and agreement is found with, previous calculations. Furthermore, we generate new results in this sector, calculating the current quadrupole moment induced by finite size gravitomagnetic effects. We also present novel results for parity violating sources, which might be due to beyond standard model physics, and show that they generate GW signals with the unique signature that the current-moment appears at 0.5PN order earlier relative to the mass-moment in the PN expansion. Parity violation also induces a new type of potential, which is proportional to the $\text{S}\cdot \text{r}$. Finally, we present new results for the dissipative force for parity violating constituents, which leads to the curious signature of a force normal to the orbit.

    ↳ hep-thastro-ph.HEgr-qchep-phJHEP(2023)·7 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.