Wed·Mar 9, 2022Wednesday·March 9, 2022

1. 01*

   Reconstruction of Missing Resonances Combining Nearest Neighbors Regressors and Neural Network Classifiers

   Alexandre Alves🇧🇷 · C. H. Yamaguchi🇧🇷

   Neutrinos, dark matter, and long-lived neutral particles traverse the particle detectors unnoticed, carrying away information about their parent particles and interaction sources needed to reconstruct key variables like resonance peaks in invariant mass distributions. In this work, we show that a $k$-nearest neighbors regressor algorithm combined with deep neural network classifiers, a $k$NN, is able to accurately recover binned distributions of the fully leptonic $WW$ mass of a new heavy Higgs boson and its Standard Model backgrounds from the observable detector level information at disposal. The output of the regressor can be used to train even stronger classifiers to separate signals and backgrounds in the fully leptonic case and guarantee the selection of on-mass-shell Higgs bosons with enhanced statistical significance. The method assumes previous knowledge of the event classes and model parameters, thus suitable for post-discovery studies.

   hep-phhep-exEPJC(2022)·9 citations
2. 02*

   A simple guide from Machine Learning outputs to statistical criteria

   Charanjit K. Khosa🇬🇧 · Veronica Sanz🇪🇸 · Michael Soughton🇪🇸

   In this paper we propose ways to incorporate Machine Learning training outputs into a study of statistical significance. We describe these methods in supervised classification tasks using a CNN and a DNN output, and unsupervised learning based on a VAE. As use cases, we consider two physical situations where Machine Learning are often used: high-$p_T$ hadronic activity, and boosted Higgs in association with a massive vector boson.

   hep-phSciPost Phys.Core(2022)·8 citations
3. 03*

   eV Hubble Scale Inflation with Radiative Plateau: Very light Inflaton, Reheating & Dark Matter in B-L Extensions

   Anish Ghoshal🇵🇱 · Nobuchika Okada🇺🇸 · Arnab Paul🇮🇳

   We study radiative plateau-like inflation \& Z${}_{BL}$-portal freeze-in fermionic dark matter (DM) in a minimal B-L extended model. The U(1)${}_{B-L}$ Higgs, responsible for heavy neutrino masses, also drives inflation in the early universe, thanks to radiative corrections from the heavy neutrinos \& the Z${}_{BL}$ gauge boson. In our benchmark choice for the U(1)${}_{B-L}$ gauge coupling $g_{B-L}\sim 10^{-4}$, a light Z${}_{BL}$ boson can be explored by current and future lifetime frontier experiments, such as FASER and FASER 2 at the LHC, SHiP, Belle II and LHCb. For the benchmark, the Hubble scale of inflation (${\mathcal{H}}_{inf}$) is very low (${\mathcal{H}}_{inf}=\mathcal{O}(100)$ eV) \& the inflaton turns out to be very light with mass of $\mathcal{O}(1)$ eV, and consequently the decay width of inflaton is extremely small. We investigate a 2-field system with the inflaton/B-L Higgs and the Standard Model (SM) Higgs, and find that the reheating with a suffuciently high temperature occurs when the water-fall direction to the SM Higgs direction opens up in the trajectory of the scalar field evolution.

   hep-phastro-ph.COPRD(2022)·9 citations
4. 04*

   3D structure of jet-induced diffusion wake in an expanding quark-gluon plasma

   Zhong Yang🇨🇳 · Tan Luo🇪🇸 · Wei Chen🇨🇳 · Long-Gang Pang🇨🇳 · Xin-Nian Wang🇨🇳

   The diffusion wake accompanying the jet-induced Mach cone provides a unique probe of the properties of quark-gluon plasma in high-energy heavy-ion collisions. It can be characterized by a depletion of soft hadrons in the opposite direction of the propagating jet. We explore the 3D structure of the diffusion wake induced by $\gamma$-triggered jets in Pb+Pb collisions at the LHC energy within the coupled linear Boltzmann transport and hydro model. We identify a valley structure caused by the diffusion wake on top of a ridge from the initial multiple parton interaction (MPI) in jet-hadron correlation as a function of rapidity and azimuthal angle. This leads to a double-peak structure in the rapidity distribution of soft hadrons in the opposite direction of the jets as an unambiguous signal of the diffusion wake. Using a two-Gaussian fit, we extract the diffusion wake and MPI contributions to the double peak. The diffusion wake valley is found to deepen with the jet energy loss as characterized by the $\gamma$-jet asymmetry. Its sensitivity to the equation of state and shear viscosity is also studied.

   hep-phnucl-thPRL(2023)·70 citations
5. 05*

   Higher-order corrections for $t\bar{t}$ production at high energies

   Nikolaos Kidonakis🇺🇸

   I present theoretical calculations of $t\bar{t}$ production cross sections through aN${}^3$LO in proton-proton collisions. I show that soft-gluon corrections dominate the perturbative expansion not only for LHC energies but also for future collider energies through 100 TeV. Detailed results are presented for various collision energies. The $K$-factors are large and increase slowly with increasing energy. The scale uncertainties decrease greatly as we move to higher perturbative orders.

   hep-ph14 citations
6. 06*

   Angular cuts to reduce the tautaubar+jet background to the higgsino signal at the LHC

   Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Dibyashree Sengupta🇹🇼 · Xerxes Tata🇺🇸

   We re-examine higgsino pair production in association with a hard QCD jet at the LHC. We focus on \ell^+\ell^- +MET +jet events from the production and subsequent decay, \tchi_2^0\to\tchi_1^0\ell^+\ell^-, of the heavier neutral higgsino. The novel feature of our analysis is that we propose angular cuts to reduce the irreducible background from Z(-> \tau\bar{\tau})+jet events more efficiently than the m_{\tau\tau}^2<0 cut that has been used by the ATLAS and CMS collaborations. Additional cuts, needed to reduce backgrounds from t\bar{t}, WWj and W/Z+\ell\bar{\ell} production, are also delineated. We evaluate the reach of LHC14 for 300 and 3000~fb^{-1} and stress that the dilepton mass distribution would serve to characterize the higgsino signal.

   hep-ph6 citations
7. 07*

   The Composite Higgs Signal at the Next Big Collider

   Kenneth Lane🇺🇸

   The Gildener-Weinberg (GW) mechanism produces a Higgs boson $H$ that is a dilaton. That is, $H$ is both naturally light and naturally aligned. It also predicts additional singly-charged and neutral Higgs bosons all of whose masses are $<500\mathrm{GeV}$ and, therefore, within reach of the LHC now. I argue that the GW Higgs is composite -- a bound state of fermions whose strong interactions are at some high, unknown scale ${\Lambda }_H>1\mathrm{TeV}$. The lone harbingers of $H$ compositeness, ones that may be accessible at the next multi-TeV collider, are isovector vector ${\rho }_H$ and axial vector $a_H$ bound states whose masses are $\mathcal{O}({\Lambda }_{\mathcal{H}})$. They decay into the only fermion-antifermion composites lighter than they are, the Higgs boson and longitudinally-polarized weak bosons: ${\rho }_H^{\pm ,0}\to W_L^{\pm }{Z}_L$, $W_L^{+}{W}_L^{-}$ and $a_H^{\pm ,0}\to W_L^{\pm }H$, $Z_{L}H$. Observing these resonant, highly-boosted weak-scale bosons would establish their composite nature.

   hep-phhep-ex4 citations
8. 08*

   Global Constraints on Yukawa Operators in the Standard Model Effective Theory

   Joachim Brod🇺🇸 · Jonathan M. Cornell🇺🇸 · Dimitrios Skodras🇩🇪 · Emmanuel Stamou🇩🇪

   CP-violating contributions to Higgs--fermion couplings are absent in the standard model of particle physics (SM), but are motivated by models of electroweak baryogenesis. Here, we employ the framework of the SM effective theory (SMEFT) to parameterise deviations from SM Yukawa couplings. We present the leading contributions of the relevant operators to the fermionic electric dipole moments (EDMs). We obtain constraints on the SMEFT Wilson coefficients from the combination of LHC data and experimental bounds on the electron, neutron, and mercury EDMs, and for the first time, we perform a combined fit to LHC and EDM data allowing the presence of CP-violating contributions from several fermion species simultaneously. Among other results, we find non-trivial correlations between EDM and LHC constraints even in the multi-parameter scans, for instance, when floating the CP-even and CP-odd couplings to all third-generation fermions.

   hep-phJHEP(2022)·43 citations
9. 09*

   On Lowest Lying ${\frac{1}{2}}^{-}$ Octet Baryons

   Chang Chen🇨🇳 · Wen-Qi Niu🇨🇳 · Han-Qing Zheng🇨🇳

   The recently proposed $N^{\ast }(890)$ $1/2^{-}$ baryon is studied in a flavor $SU(3)$ scheme with $K$ matrix unitarization, by fitting to low energy cross section and phase shift data. It is found that $N^{\ast }(890)$ co-exists with low lying poles in other channels, which have been extensively discussed in the literature, though they belong to different octets, in the $SU(3)$ limit. Hence the existence of $N^{\ast }(890)$ is further verified.

   hep-phnucl-thCPC(2022)·5 citations
10. 10*

    Combined signatures of heavy Higgses and vectorlike fermions at the HL-LHC

    Radovan Dermisek🇺🇸 · Junichiro Kawamura🇰🇷 · Enrico Lunghi🇺🇸 · Navin McGinnis🇨🇦 · Seodong Shin🇰🇷

    In extensions of two Higgs doublet models with vectorlike quarks and leptons the decays of new scalars or fermions can be altered by the presence of the other, depending on the hierarchy of new physics. If new fermions are heavier than Higgses, their decays may be dominated by cascade decays through charged and neutral heavy Higgs bosons. In the opposite hierarchy, the decay of a heavy Higgs can lead to single production of vectorlike quarks and leptons when Yukawa couplings to SM fermions are present. We explore the resulting novel collider signatures in either case and present projected sensitivities of future runs of the LHC to the masses and branching ratios of new fermions and heavy Higgses. Importantly, we discuss kinematic challenges of the signatures and suggest strategic observables which could be adopted in future analyses. Interpreting the prospective reach of the LHC in the context of a type-II 2HDM, we find that in the presence of vectorlike fermions heavy Higgs boson masses slightly above 2 TeV can be explored at the HL-LHC even at low $\tan \beta$. For heavy Higgs decays through vectorlike leptons, this reach extends to slightly above 3 TeV for $\tan \beta \gtrsim 10$. Further, these search strategies imply a reach for vectorlike quark and lepton masses close to 2.4 TeV and 1.5 TeV, respectively. This article is partly based on Refs. [1-6]

    hep-ph5 citations
11. 11*

    The $N/D$ study on the singularity structure of $\pi N$ scattering amplitudes

    Qu-Zhi Li🇨🇳

    The $N/D$ method is used to study the $S_{11}$ channel low energy $\pi N$ scattering amplitude. The input of left cuts are obtained from various phenomenological models. With the aid of the production representation, the total phase shifts can be decomposed into different contributions, and it further reveals that the existence of subthreshold resonance $N^{\ast }(890)$ doesn't depend on the details of the dynamical input. Additionally, it is found that there exist virtual states in partial waves, which are induced by the $u$ channel nucleon exchanges. These virtual states accumulate at the end point of the $u$ channel segment cut. The end point is hence the essential singularity of the full amplitude on the second sheet of complex $s$ plane.

    hep-phPoS(2024)·0 citations
12. 12*

    Physics Opportunities for the Fermilab Booster Replacement

    John Arrington🇺🇸 · Joshua Barrow🇺🇸 · Brian Batell🇺🇸 · Robert Bernstein🇺🇸 · Nikita Blinov🇨🇦 · S. J. Brice🇺🇸 · Ray Culbertson🇺🇸 · Patrick deNiverville🇺🇸 · Vito Di Benedetto🇺🇸 · Jeff Eldred🇺🇸 · Angela Fava🇺🇸 · Laura Fields🇺🇸 and 40 other authors

    This white paper presents opportunities afforded by the Fermilab Booster Replacement and its various options. Its goal is to inform the design process of the Booster Replacement about the accelerator needs of the various options, allowing the design to be versatile and enable, or leave the door open to, as many options as possible. The physics themes covered by the paper include searches for dark sectors and new opportunities with muons.

    hep-phhep-exphysics.acc-ph18 citations
13. 13*

    Dark Matter and Muon $g-2$ Anomaly via Scale Symmetry Breaking

    Parsa Ghorbani🇮🇷

    The Standard Model (SM) without the Higgs mass term is scale invariant. Gildener and Weinberg generalized the scale invariant standard model (SISM) by including the multiplication of scalars in quartic forms. They pointed out that along the flat direction only one scalar -- called the scalon -- is classically massless and all other scalars are massive. Here we choose a SISM with one scalon and one heavy scalar and extend that further respecting the scale invariance by a vector-like lepton (VLL). By an appropriate choice of the flat direction, the heavy scalar enjoys the ${\mathbb{Z}}_2$ symmetry and is assumed as DM particle. The scalon connects the visible and dark sector via the Higgs-portal and by interacting with both the muon lepton and the VLL. The VLL is charged under $U(1{)}_Y$ and interacts with $\gamma /Z$ bosons. We show that the model correctly accounts for the observed dark matter (DM) relic abundance in the universe, while naturally evading the current and future bounds from direct detection (DD) experiments. Moreover, the model is capable to explain the $(g-2{)}_{\mu }$ anomaly observed in Fermilab. We also show a feature in SISM scenarios which is not present in other Higgs-portal models; despite having the Higgs-portal term $|H{|}^2{s}^2$ ($s$ being the scalon) in SISM, the effective potential after the electroweak symmetry breaking lacks an important expected vertex $h{s}^2$. This property immediately forbids the tree-level invisible Higgs decay $h\to ss$ and the one-loop Higgs decay $h\to {\mu }^{+}{\mu }^{-}$.

    hep-phhep-thJHEP(2022)·7 citations
14. 14*

    Universality of linear perturbations in SU($N$)-natural inflation

    Tomohiro Fujita🇯🇵 · Kai Murai🇯🇵 · Ryo Namba🇯🇵

    We prove the universality of predictions for linear perturbations from the entire class of models of inflation driven by a pseudo-scalar field coupled to an SU($N$) gauge boson, where SU($2$) subgroups in the SU($N$) crossed with the background spatial SO($3$) spontaneously break into a single SO($3$). The effect of which SU($2$) subgroup in SU($N$) acquires a VEV through spontaneous symmetry breaking can be quantified by a single parameter $\lambda$, which always appears in combination with the gauge coupling constant $g$. In the linear perturbations, as well as the background system, the same dynamics and predictions as in the chromo-natural inflation hold for its SU($N$) extension by replacing $g\to g\lambda$. The latter models thereby draw the same prediction curve on the $n_s$-$r$ plane as the former at the tree level as long as $g\lambda$ stays constant during inflation. We briefly discuss possible transitions from one value of $\lambda$ to another during inflation and the observational prospects.

    hep-phastro-ph.COPRD(2022)·19 citations
15. 15*

    Enhanced charm CP asymmetries from final state interactions

    Ignacio Bediaga🇧🇷 · Tobias Frederico🇧🇷 · Patricia C Magalhães🇧🇷

    We show that final state interactions (FSI) within a CPT invariant two-channel framework can enhance the charge-parity (CP) violation difference between $D^0\to {\pi }^{-}{\pi }^{+}$ and $D^0\to K^{-}{K}^{+}$ decays up to the current experimental value. This result relies upon: (i) the dominant tree level diagram, (ii) the well-known experimental values for the $D^0\to {\pi }^{-}{\pi }^{+}$ and $D^0\to K^{-}{K}^{+}$ branching ratios, and (iii) the $\pi \pi \to \pi \pi$ and $\pi \pi \to KK$ scattering data to extract the strong phase difference and inelasticity. Based on well-grounded theoretical properties, we find the sign and bulk value of the $\Delta A_{CP}$ and $A_{CP}(D^0\to {\pi }^{-}{\pi }^{+})$ recently observed by the LHCb Collaboration.

    hep-phhep-exPRL(2023)·57 citations
16. 16*

    Studying $\Delta L=2$ Lepton Flavor Violation with Muons

    Alexey A. Petrov🇺🇸 · Renae Conlin🇺🇸 · Cody Grant🇺🇸

    Flavor violating processes in the lepton sector have highly suppressed branching ratios in the standard model. Thus, observation of lepton flavor violation (LFV) constitutes a clear indication of physics beyond the standard model (BSM). We review new physics searches in the processes that violate the conservation of lepton (muon) flavor by two units with muonia and muonium--antimuonium oscillations.

    hep-phhep-exUniverse(2022)·11 citations
17. 17*

    Strong decays of excited $2^{+}$ charmed mesons

    Xiao-Ze Tan🇨🇳 · Tianhong Wang🇨🇳 · Yue Jiang🇨🇳 · Qiang Li🇨🇳 · Lei Huo🇨🇳 · Guo-Li Wang🇨🇳

    The new charmed resonance $D_2^{\ast }(3000)$ was observed by the LHCb Collaboration in $B$ decays. In this paper, by assigning it as four possible excited states of the $2^{+}$ family, we use the instantaneous Bethe-Salpeter method to calculate their Okubo-Zweig-Iizuka-allowed two-body strong decays. The results of $1^3{F}_2$ and $3^3{P}_2$ states deviate from the present experimental observation while $2^3{P}_2$ and $2^3{F}_2$ are in the error range. Our study also reveals that the widths of these states depend strongly on the masses. Due to the large uncertainties and different mass input, variable models get inconsistent conclusions at the moment. The analysis in this work can provide essential assistance for future measurements and investigations.

    hep-phPRD(2022)·2 citations
18. 18*

    Complementarity of experiments in probing the non-relativistic effective theory of dark matter-nucleon interactions

    Anja Brenner🇩🇪 · Gonzalo Herrera🇩🇪 · Alejandro Ibarra🇩🇪 · Sunghyun Kang🇰🇷 · Stefano Scopel🇰🇷 · Gaurav Tomar🇩🇪

    The non-relativistic effective theory of dark matter-nucleon interactions depends on 28 coupling strengths for dark matter spin up to 1/2. Due to the vast parameter space of the effective theory, most experiments searching for dark matter interpret the results assuming that only one of the coupling strengths is non-zero. On the other hand, dark matter models generically lead in the non-relativistic limit to several interactions which interfere with one another, therefore the published limits cannot be straightforwardly applied to model predictions. We present a method to determine a rigorous upper limit on the dark matter-nucleon interaction strength including all possible interferences among operators. We illustrate the method to derive model independent upper limits on the interaction strengths from the null search results from XENON1T, PICO-60 and IceCube. For some interactions, the limits on the coupling strengths are relaxed by more than one order of magnitude. We also present a method that allows to combine the results from different experiments, thus exploiting the synergy between different targets in exploring the parameter space of dark matter-nucleon interactions.

    hep-phhep-exJCAP(2022)·18 citations
19. 19*

    Freeze-In of radiative keV-scale neutrino dark matter from a new $\text{U}(1{)}_{\text{B-L}}$

    Maximilian Berbig🇩🇪

    We extend the Dirac Scotogenic model with the aim of realizing neutrino masses together with the mass of a keV-scale dark matter (DM) candidate via the same one-loop topology. Two of the Standard Model (SM) neutrinos become massive Dirac fermions while the third one remains massless. Our particle content is motivated by an anomaly free $\text{U}(1{)}_{\text{B-L}}$ gauge symmetry with exotic irrational charges and we need to enforce an additional ${\mathcal{Z}}_5$ symmetry. The dark matter candidate does not mix with the active neutrinos and does not have any decay modes to SM particles. DM is produced together with dark radiation in the form of right handed neutrinos via out of equilibrium annihilations of the SM fermions mediated by the heavy B-L gauge boson. In order to avoid DM over-production from Higgs decays and to comply with Lyman-$\alpha$ bounds we work in a low temperature reheating scenario with $4\text{MeV}\lesssim T_{\text{RH}}\lesssim 5\text{GeV}$. Our setup predicts a contribution to $\Delta N_{\text{eff.}}$ that decreases for larger DM masses and is below the sensitivity of upcoming precision measurements such as CMB-S4. A future observation of a signal with $\Delta N_{\text{eff.}}\gtrsim 0.012$ would exclude our scenario. We further sketch how inflation, reheating and Affleck-Dine baryogenesis can also be potentially realized in this unified framework.

    hep-phJHEP(2022)·17 citations
20. 20*

    Combining thermal resummation and gauge invariance for electroweak phase transition

    Philipp Schicho🇫🇮 · Tuomas V. I. Tenkanen🇸🇪 · Graham White🇯🇵

    For computing thermodynamics of the electroweak phase transition, we discuss a minimal approach that reconciles both gauge invariance and thermal resummation. Such a minimal setup consists of a two-loop dimensional reduction to three-dimensional effective theory, a one-loop computation of the effective potential and its expansion around the leading-order minima within the effective theory. This approach is tractable and provides formulae for resummation that are arguably no more complicated than those that appear in standard techniques ubiquitous in the literature. In particular, we implement renormalisation group improvement related to the hard thermal scale. Despite its generic nature, we present this approach for the complex singlet extension of the Standard Model which has interesting prospects for high energy collider phenomenology and dark matter predictions. The presented expressions can be used in future studies of phase transition thermodynamics and gravitational wave production.

    hep-phJHEP(2022)·95 citations
21. 21*

    Upper limit on the axion-photon coupling from magnetic white dwarf polarization

    Christopher Dessert🇺🇸 · David Dunsky🇺🇸 · Benjamin R. Safdi🇺🇸

    Polarization measurements of thermal radiation from magnetic white dwarf (MWD) stars have been proposed as a probe of axion-photon mixing. The radiation leaving the surface of the MWD is unpolarized, but if low-mass axions exist then photons polarized parallel to the direction of the MWD's magnetic field may convert into axions, which induces a linear polarization dependent on the strength of the axion-photon coupling $g_{a\gamma \gamma }$. We model this process by using the formalism of axion-photon mixing in the presence of strong-field vacuum birefringence to show that of all stellar types MWDs are the most promising targets for axion-induced polarization searches. We then consider linear polarization data from multiple MWDs, including SDSS J135141 and Grw+70${}^{\circ }$8247, to show that after rigorously accounting for astrophysical uncertainties the axion-photon coupling is constrained to $|g_{a\gamma \gamma }|\lesssim 5.4\times 10^{-12}$ GeV${}^{-1}$ at 95% confidence for axion masses $m_a\lesssim 3\times 10^{-7}$ eV. This upper limit puts in tension the previously-suggested explanation of the anomalous transparency of the Universe to TeV gamma-rays in terms of axions. We identify MWD targets for which future data and modeling efforts could further improve the sensitivity to axions.

    hep-phastro-ph.SRPRD(2022)·149 citations
22. 22*

    Higgs Precision at a 125 GeV Muon Collider

    Jorge de Blas🇪🇸 · Jiayin Gu🇨🇳 · Zhen Liu🇺🇸

    The $s$-channel resonant production of the Higgs boson at a 125 GeV muon collider enables a unique way to determine the Higgs properties. However, a clear picture of the achievable Higgs precision has not yet been established. We perform a phenomenological study of the Higgs measurements at such resonant muon collider Higgs factory and present a systematic, detailed, and consistent extraction of Higgs precision measurements. Many new aspects about the lineshape scan, including the scaling with luminosity, optimal scan range, minimal scan steps, correlations with exclusive measurement, effective cross-section modeling, etc., are quantitatively studied in this work. All major exclusive Higgs channels are simulated and analyzed with Standard Model background, detection efficiencies, acceptance, angular distributions, and cross-channel correlations. Global analyses of the Higgs couplings are performed in the $\kappa$ framework and the effective-field-theory one. The results suggest that the 125 GeV muon-collider Higgs factory provides significant improvement to the Higgs coupling reach of the HL-LHC and provides independent and distinct Higgs precision information concerning future $e^{+}{e}^{-}$ colliders. We report results for both $5{\mathrm{fb}}^{-1}$ and $20{\mathrm{fb}}^{-1}$ integrated luminosity. These results provide comprehensive and quantitative physics understandings helpful in planning for the muon collider roadmap and global high-energy physics programs.

    hep-phhep-exPRD(2022)·43 citations
23. 23*

    Impact of Sommerfeld Effect and Bound State Formation in Simplified $t$-Channel Dark Matter Models

    Mathias Becker🇩🇪 · Emanuele Copello🇩🇪 · Julia Harz🇩🇪 · Kirtimaan A. Mohan🇺🇸 · Dipan Sengupta🇺🇸

    The existence of a dark matter model with a rich dark sector could be the reason why WIMP dark matter has evaded its detection so far. For instance, colored co-annihilation naturally leads to the prediction of heavier dark matter masses. Importantly, in such a scenario the Sommerfeld effect and bound state formation must be considered in order to accurately predict the relic abundance. Based on the example of the currently widely studied $t$-channel simplified model with a colored mediator, we demonstrate the importance of considering these non-perturbative effects for correctly inferring the viable model parameters. We emphasize that a flat correction factor on the relic abundance is not sufficient in this context. Moreover, we find that parameter space thought to be excluded by direct detection experiments and LHC searches remains still viable. Additionally, we illustrate that long-lived particle searches and bound-state searches at the LHC can play a crucial role in probing such a model. We demonstrate how future direct detection experiments will be able to close almost all of the remaining windows for freeze-out production, making it a highly testable scenario.

    hep-phhep-exJHEP(2022)·31 citations
24. 24*

    The phenomenology of the exotic hybrid nonet with ${\pi }_1(1600)$ and ${\eta }_1(1855)$

    Vanamali Shastry🇵🇱 · Christian S. Fischer🇩🇪 · Francesco Giacosa🇵🇱

    We study the decays of the $J^{PC}=1^{-+}$ hybrid nonet using a Lagrangian invariant under the flavor symmetry, parity reversal, and charge conjugation. We use the available experimental data, the lattice predictions, and the flavor constraints to evaluate the coupling strengths of the ${\pi }_1(1600)$ to various two-body mesonic states. Using these coupling constants, we estimate the partial widths of the two-body decays of the hybrid pion, kaon and the isoscalars. We find that the hybrid kaon can be nearly as broad as the ${\pi }_1(1600)$. Quite remarkably, we find also that the light isoscalar must be significantly narrow while the width of the heavy isoscalar can be matched to the recently observed ${\eta }_1(1855)$.

    hep-phhep-exhep-latPLB(2022)·51 citations
25. 25*

    Electroweak ALP Searches at a Muon Collider

    Yunjia Bao🇺🇸 · JiJi Fan🇺🇸 · Lingfeng Li🇺🇸

    A high-energy muon collider with center-of-mass energy around and above 10 TeV is also a vector boson fusion (VBF) machine, due to the significant virtual electroweak (EW) gauge boson content of high-energy muon beams. This feature, together with the clean environment, makes it an ideal collider to search for TeV-scale axion-like particles (ALP) coupling to Standard Model EW gauge bosons, which current and other future colliders have limited sensitivities to. We present detailed analyses of heavy ALP searches in both the VBF and associated production channels at a muon collider with different running benchmarks. We also show projected constraints on the ALP couplings in the effective field theory, including an operator with its coefficient not determined by the mixed Peccei-Quinn anomaly. We demonstrate that a muon collider could probe new ALP parameter space and push the sensitivities of the couplings between the ALP and EW gauge bosons by one order of magnitude compared to HL-LHC. The projected limits and search strategies for ALPs could also be applied to other types of resonances coupling to EW gauge bosons.

    hep-phhep-exJHEP(2022)·48 citations
26. 26*

    Constraining Axion-Like Particles with HAWC Observations of TeV Blazars

    Sunniva Jacobsen🇸🇪 · Tim Linden🇸🇪 · Katherine Freese🇺🇸

    Axion-like particles (ALPs) are a broad class of pseudo-scalar bosons that generically arise from broken symmetries in extensions of the standard model. In many scenarios, ALPs can mix with photons in regions with high magnetic fields. Photons from distant sources can mix with ALPs, which then travel unattenuated through the Universe, before they mix back to photons in the Milky Way galactic magnetic field. Thus, photons can traverse regions where their signals would normally be blocked or attenuated. In this paper, we study TeV $\gamma$-ray observations from distant blazars, utilizing the significant $\gamma$-ray attenuation expected from such signals to look for excess photon fluxes that may be due to ALP-photon mixing. We find no such excesses among a stacked population of seven blazars and constrain the ALP-photon coupling constant to fall below $\sim$3$\times$10${}^{-11}$ GeV${}^{-1}$ for ALP masses below 300 neV. These results are competitive with, or better than, leading terrestrial and astrophysical constraints in this mass range.

    hep-phastro-ph.HEJCAP(2023)·40 citations
27. 27*

    Exploring $\Lambda$CDM extensions with SPT-3G and Planck data: 4$\sigma$ evidence for neutrino masses and implications of extended dark energy models for cosmological tensions

    Anton Chudaykin🇨🇦 · Dmitry Gorbunov🇷🇺 · Nikita Nedelko🇷🇺

    We present new cosmological constraints in a set of motivated extensions of the $\Lambda$CDM model using the polarization and gravitational lensing measurements from the South Pole Telescope and the Planck CMB temperature observations at large angular scales. In all cosmological scenarios, this CMB data brings the clustering measurements into agreement with the low-redshift probes of large-scale structure. Combining the SPT-3G, SPTpol and Planck large-scale temperature data with the latest full-shape BOSS and BAO measurements, information from the weak lensing and photometric galaxy clustering, and Pantheon supernova set we find a $4\sigma$ evidence for nonzero neutrino mass, $\sum m_{\nu }=0.22\pm 0.06\mathrm{eV}$.Breaking the CMB degeneracies between $\sum m_{\nu }$ and the cosmological parameters by the BOSS data is a major contribution to our neutrino mass measurement. The future CMB data would allow for investigating this measurement. Then we explore the possibility of dynamical dark energy with two model-independent approaches: one introduces a phantom crossing in dark energy equation of state, another provides with a sharp transition in the dark energy evolution. For the combination of all data considered, the both models predict $H_0\simeq 68\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ being in a $\sim 3\sigma$ tension with the SH0ES constraint. However, when the local Type Ia supernovae are calibrated by Cepheids, the late Universe scenarios suggest significantly higher values of $H_0$ consistent with SH0ES. Our work draws attention to the supernova absolute magnitude calibration as one of the issues on the way to reconcile the $H_0$ tension.

    ↳ astro-ph.COhep-ph29 citations
28. 28*

    On-shell Lagrangian of an ideal gas

    P.P. Avelino🇵🇹 · R.P.L. Azevedo🇵🇹

    In the context of general relativity, both energy and linear momentum constraints lead to the same equation for the evolution of the speed of free localized particles with fixed proper mass and structure in a homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker universe. In this paper we extend this result by considering the dynamics of particles and fluids in the context of theories of gravity nonminimally coupled to matter. We show that the equation for the evolution of the linear momentum of the particles may be obtained irrespective of any prior assumptions regarding the form of the on-shell Lagrangian of the matter fields. We also find that consistency between the evolution of the energy and linear momentum of the particles requires that their volume-averaged on-shell Lagrangian and energy-momentum tensor trace coincide (${\mathcal{L}}_{\mathrm{on}-\mathrm{shell}}=T$). We further demonstrate that the same applies to an ideal gas composed of many such particles. This result implies that the two most common assumptions in the literature for the on-shell Lagrangian of a perfect fluid (${\mathcal{L}}_{\mathrm{on}-\mathrm{shell}}=\mathcal{P}$ and ${\mathcal{L}}_{\mathrm{on}-\mathrm{shell}}=-\rho$, where $\rho$ and $\mathcal{P}$ are the proper density and pressure of the fluid, respectively) do not apply to an ideal gas, except in the case of dust (in which case $T=-\rho$).

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2022)·18 citations
29. 29*

    Topological Corrections and Conformal Backreaction in the Einstein Gauss-Bonnet/Weyl Theories of Gravity at D=4

    Claudio Corianò🇮🇹 · Matteo Maria Maglio🇩🇪 · Dimosthenis Theofilopoulos🇮🇹

    We investigate the gravitational backreaction, generated by coupling a general conformal sector to external, classical gravity, as described by a conformal anomaly effective action. We address the issues raised by the regularization of the topological Gauss-Bonnet and Weyl terms in these actions and the use of dimensional regularization (DR). We discuss both their local and nonlocal expressions, as possible IR and UV descriptions of conformal theories, below and above the conformal breaking scale. Our discussion overlaps with several recent studies of dilaton gravities - obtained via a certain singular limit of the Einstein-Gauss-Bonnet (EGB) theory - originally introduced as a way to bypass Lovelock's theorem. We show that nonlocal, purely gravitational realizations of such EGB theories, quadratic in the dilaton field, beside their local quartic forms, are possible by a finite renormalization of the Euler density. Such nonlocal versions, which are deprived of any scale, can be expanded, at least around flat space, in terms of the combination $R{\square }^{-1}$ times multiple variations of the anomaly functional, as pointed out in recent studies at $d=4$. Similar conclusions can be drawn for the proposed nonlocal EGB theory. The expansion emerges from previous investigations of the anomalous conformal Ward identities that constrain such theories around the flat spacetime limit in momentum space.

    ↳ hep-thgr-qchep-phEPJC(2022)·14 citations
30. 30*

    Modelling Quintessential Inflation in Palatini Modified Gravity

    Konstantinos Dimopoulos🇬🇧 · Alexandros Karam🇪🇪 · Samuel Sánchez López🇬🇧 · Eemeli Tomberg🇪🇪

    We study a model of quintessential inflation constructed in $R^2$ modified gravity with a non-minimally coupled scalar field, in the Palatini formalism. Our non-minimal inflaton field is characterised by a simple exponential potential. We find that successful quintessential inflation can be achieved with no fine-tuning on the model parameters. Predictions on the characteristics of dark energy will be tested by observations in the near future, while contrast with existing observations provides insights on the modified gravity background, such as the value of the non-minimal coupling and its running.

    ↳ gr-qcastro-ph.COhep-phhep-thGalaxies(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.