Fri·Oct 29, 2021Friday·October 29, 2021

1. 01*

   Muon pair production via $e^{+}{e}^{-}$ annihilation in the presence of a circularly polarized laser field

   M. Ouali🇲🇦 · M. Ouhammou🇲🇦 · S. Taj🇲🇦 · R. Benbrik🇲🇦 · B. Manaut🇲🇦

   In this paper, we have investigated the elementary particle reaction $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$ that results from the electron-positron interaction, at the leading order, with an intense laser wave of circular polarization. We have derived, by annalytical means, the laser-assisted differential cross section expression by using the scattering matrix approach. We have analyzed the energy and the number of exchanged photons dependence of muon pair production in electron-positron annihilation at different centre of mass energies including the $Z$-boson peak. For this reason, a wide range of high centre of mass energies relevant to future $e^{+}{e}^{-}$ collider were covered to study the cross section behavior. We have found that, for a given number of exchanged photons, laser field strength and frequency, the circularly polarized laser field decreases the total cross section by several orders of magnitudes.

   hep-phLaser Phys.(2022)·5 citations
2. 02*

   New $Z_c$ spectroscopy or Landau singularities? Searches in Heavy Ion Collisions could help decide

   Felipe J. Llanes-Estrada🇪🇸 · Luciano M. Abreu🇧🇷

   A constellation of quarkonium-mass peaks has been reported in the last decade, opening what could be an entire new spectroscopy of nuclear-physics like complexity. Salient among these structures are the $Z_c$, much analyzed at BESIII as nicely summarised by J.~Zhao at this conference. Their stature as new hadron states has often been challenged by proposals that the peaks arise from triangle singularities instead, because they appear in three-body reactions and often satisfy the special kinematic conditions of the Coleman-Norton theorem. To experimentally decide, we should like to resort to different reactions erasing the kinematic coincidence, and see whether each peak survives. We observe that the most universal "eraser" is the medium created in Heavy Ion Collisions, because its high temperature often affects the masses and widths of the particles participating in the reaction: if additionally the triangle reaction is completed during the lifetime of the fireball, our computations in thermal field theory show that the triangle singularities do not survive the hot hadron phase (much less the hotter quark-gluon plasma). On the contrary, ordinary quarkonia are affected but often survive the fireball and molecular-like states are also routinely detected. We have provided several examples, and here investigate the exotic $Z_c(4020{)}^{\pm }\to {\pi }^{\pm }{h}_c$ peak (produced against a ${\pi }^{\mp }$ in $e^{+}{e}^{-}$ collisions). If, as has been proposed during the debates, it is produced or enhanced by a $D_1{D}^{\ast }{D}^{\ast }$ triangle loop, the estimate here reported suggests its disappearance near the critical temperature of the confinement/deconfinement phase transition, so any future detection in heavy-ion collision data would suggest it to be a real hadron, with its absence leaning towards the singularity interpretation.

   hep-phPoS(2022)·6 citations
3. 03*

   Time variation of the atmospheric neutrino flux at dark matter detectors

   Yi Zhuang🇺🇸 · Louis E. Strigari🇺🇸 · Rafael F. Lang🇺🇸

   The cosmic ray flux at the lowest energies, $\lesssim 10$ GeV, is modulated by the solar cycle, inducing a time variation that is expected to carry over into the atmospheric neutrino flux at these energies. Here we estimate this time variation of the atmospheric neutrino flux at five prospective underground locations for multi-tonne scale dark matter detectors (CJPL, Kamioka, LNGS, SNOlab and SURF). We find that between solar minimum and solar maximum, the normalization of the flux changes by $\sim 30\%$ at a high-latitude location such as SURF, while it changes by a smaller amount, $\lesssim 10\%$, at LNGS. A dark matter detector that runs for a period extending through solar cycles will be most effective at identifying this time variation. This opens the possibility to distinguish such neutrino-induced nuclear recoils from dark matter-induced nuclear recoils, thus allowing for the possibility of using timing information to break through the "neutrino floor."

   hep-phastro-ph.HEPRD(2022)·17 citations
4. 04*

   Jet Broadening in the Opacity and Twist Expansions

   Hannah Clayton🇿🇦 · Matthew D. Sievert🇺🇸 · W. A. Horowitz🇿🇦

   We compute the in-medium jet broadening $⟨p_{\perp }^2⟩$ to leading order in energy in the opacity expansion. At leading order in ${\alpha }_s$ the elastic energy loss gives a jet broadening that grows with $\ln E$. The next-to-leading order in ${\alpha }_s$ result is a jet narrowing, due to destructive LPM interference effects, that grows with ${\ln }^{2}E$. We find that in the opacity expansion the jet broadening asymptotics are -- unlike for the mean energy loss -- extremely sensitive to the correct treatment of the finite kinematics of the problem; integrating over all emitted gluon transverse momenta leads to a prediction of jet broadening rather than narrowing. We compare the asymptotics from the opacity expansion to a recent twist-4 derivation of $⟨p_{\perp }^2⟩$ and find a qualitative disagreement: the twist-4 derivation predicts a jet broadening rather than a narrowing. Comparison with current jet measurements cannot distinguish between the broadening or narrowing predictions. We comment on the origin of the difference between the opacity expansion and twist-4 results.

   hep-phnucl-thEPJC(2022)·11 citations
5. 05*

   Role of bound states and resonances in scalar QFT at nonzero temperature

   Subhasis Samanta🇵🇱 · Francesco Giacosa🇵🇱

   We study the thermal properties of quantum field theories (QFT) with three-leg interaction vertices $g{\phi }^3$ and $gS{\phi }^2$ ($\phi$ and $S$ being scalar fields), which constitute the relativistic counterpart of the Yukawa potential. We follow a non-perturbative unitarized one-loop resummed technique for which the theory is unitary and well-defined for a large range of values of the coupling constant $g$. Using the partial wave decomposition of two-body scattering we calculate the phase shifts, whose derivatives are used to infer the pressure of the system at nonzero temperature by using the so-called phase shift formalism. A $\phi \phi$ bound state is formed when the coupling $g$ is larger than a certain critical value. As the main outcomes of this work, we estimate the influence of particle interaction on the pressure (both without and with the bound state), and we demonstrate that the latter is always continuous as a function of the coupling constant $g$ (no sudden jumps occurs when the bound state forms), and we show that the contribution of the bound state to the pressure does not count as \textit{one} state in the thermal gas, since a cancellation with the residual $\phi \phi$ interaction occurs. The amount of this cancellation depends on the details of the model and its parameters and a variety of possible scenarios is presented. %Moreover, even when no bound state occurs, we estimate the role of the interaction (including a resonance in the $gS{\phi }^2$ theory), which is in general non-negligible. We also show how the overall effect of the interaction, including eventual resonances and bound states, can be formally described by a unique expression that makes use of the phase shift continued below the threshold.

   hep-phhep-thPRD(2023)·8 citations
6. 06*

   The pion-photon transition form factor at two loops in QCD

   Jing Gao🇨🇳 · Tobias Huber🇩🇪 · Yao Ji🇩🇪 · Yu-Ming Wang🇨🇳

   We report on the fully analytic calculation of the leading-power contribution to the photon-pion transition form factor $\gamma {\gamma }^{\ast }\to {\pi }^0$ at two loops in QCD. The applied techniques are based on hard-collinear factorization, together with modern multi-loop methods. We focus both, on the technical details such as the treatment of evanescent operators, and the phenomenological implications. Our results indicate that the two-loop correction is numerically comparable to the one-loop effect in the same kinematic domain. We also demonstrate that our results will play a key role in disentangling various models for the twist-two pion distribution amplitude thanks to the envisaged precision at Belle II.

   hep-phSciPost Phys.Proc.(2022)·2 citations
7. 07*

   Momentum-Current Gravitational Multipoles of Hadrons

   Xiangdong Ji🇺🇸 · Yizhuang Liu🇵🇱

   We study multipole expansion of the momentum currents in hadrons, with three series $S^{(J)}$, ${\tilde{T}}^{(J)}$, and $T^{(J)}$, in connection with the gravitational fields generated nearby. The momentum currents are related to their energy-momentum form factors, which in principle can be probed through processes like deeply-virtual Compton scattering currently studied at JLab 12 GeV facility and future Electron Ion Collider. We define the leading momentum-current multipoles, tensor monopole $\tau$ ($T0$) and scalar quadrupole ${\hat{\sigma }}^{ij}$ ($S2$) moments, relating the former to the so-called $D$-term in the literature. We calculate the momentum current distribution in hydrogen atom and its monopole moment in the basic unit of ${\tau }_0={\hslash }^2/4M$, showing that the sign of $D$-term has little to do with mechanical stability. The momentum current distribution also strongly modifies the static gravitational field inside hadrons.

   hep-phhep-latnucl-exnucl-thPRD(2022)·49 citations
8. 08*

   Effects of beta function on mass and melting temperature for scalar glueballs in AdS/QCD models at finite temperature

   Alfredo Vega🇨🇱 · Amanda Rodriguez🇨🇱

   We consider an extension to finite temperature in an AdS/ QCD model, which regards anomalous dimension contributions to get a bulk mass depending on beta function. We study the effect of beta function on mass as a function of temperature and melting temperature for scalar glueballs.

   hep-phhep-thEPJA(2022)·2 citations
9. 09*

   Study hadron property and structure in high energy multiproduction process

   Shi-Yuan Li🇨🇳

   In high energy scattering, multiproduction process is unique in its relevance to the total cross section and in its global property such as rapidity and other kinematic distributions. If there is hard interaction, the jet rate and structure is a good arena of perturbative chromodynamics. However, once any hadron is specified, its property and structure must make sense while the global and/or perturbative chromodynamics mechanism still can put important constrains. The relation of the hadron property and structure with its production cross section, distribution etc. can be much more complex than its decay width. In one hand there are many difficulties and challenges in calculation; on the other hand, production process provides unique way to study the details of property and structure of the hadron, which is beyond the approach of its decay process. Here I review our works on such topic in recent years, mainly on the multiquark state production in multiproduction process and the Bethe-Salpeter wave function in exclusive process. For the former, I emphasize on the unitarity of hadronization process and relevant models, so that Almost No multiquark state is observed in multiproduction process; I also address how to calculate hadron molecule production in multiproduction process; the most recent observed $T_{cc}^{+}$ is also stated with its relevance to colour and baryon number fluctuation of the preconfinement clusters. For the latter, I emphasize the Dirac structure of the hadron-quark coupling vertex.

   hep-phSciPost Phys.Proc.(2022)·0 citations
10. 10*

    Causal representation and numerical evaluation of multi-loop Feynman integrals

    William J. Torres Bobadilla🇩🇪

    The loop-tree duality (LTD) has become a novelty alternative to bootstrap the numerical evaluation of multi-loop scattering amplitudes. It has indeed been found that Feynman integrands, after the application of LTD, display a representation containing only physical information, the so-called causal representation. In this talk, we discuss the all-loop causal representation of multi-loop Feynman integrands, recently found in terms of features that describe a loop topology, vertices and edges. Likewise, in order to elucidate the numerical stability in LTD integrands, we present applications that involve numerical evaluations of two-loop planar and non-planar triangles with presence of several kinematic invariants.

    hep-phhep-th0 citations
11. 11*

    Exclusive $pp\to pp{K}^{\ast 0}{\bar{K}}^{\ast 0}$ reaction: $f_2(1950)$ resonance versus diffractive continuum

    Piotr Lebiedowicz🇵🇱

    The exclusive reaction $pp\to pp(K^{\ast 0}{\bar{K}}^{\ast 0}\to K^{+}{\pi }^{-}{K}^{-}{\pi }^{+})$ for the LHC experiments is discussed. The amplitudes for the reaction are formulated within the tensor-pomeron approach. We consider two diffractive mechanisms: the $f_2(1950)$ $s$-channel exchange mechanism and the $K^{\ast 0}$-exchange mechanism. First mechanism is a candidate for central diffractive production of tensor glueball and the second one is an irreducible continuum. Comparison with data from WA102 experiment are made and predictions for LHC experiments are given. We find that including the continuum contribution alone one can describe the WA102 data reasonably well. A similar behaviour of the continuum and resonance contributions makes an identification of a broad tensor-glueball state in this reaction rather difficult.

    hep-phPoS(2022)·0 citations
12. 12*

    Two-component millicharged dark matter and the EDGES 21cm signal

    Qiaodan Li🇨🇳 · Zuowei Liu🇨🇳

    We propose a two-component dark matter explanation to the EDGES 21 cm anomalous signal. The heavier dark matter component is long-lived whose decay is primarily responsible for the relic abundance of the lighter dark matter which is millicharged. To evade the constraints from CMB, underground dark matter direct detection, and XQC experiments, the lifetime of the heavier dark matter has to be larger than $0.1{\tau }_U$, where ${\tau }_U$ is the age of the universe. Our model provides a viable realization of the millicharged dark matter model to explain the EDGES 21 cm, since the minimal model in which the relic density is generated via thermal freeze-out is ruled out by various constraints.

    hep-phastro-ph.COCPC(2022)·12 citations
13. 13*

    Entropy per rapidity in Pb-Pb central collisions using Thermal and Artificial neural network(ANN) models at LHC energies

    D. M. Habashy🇪🇬 · Mahmoud Y. El-Bakry🇪🇬 · Werner Scheinast🇷🇺 · Mahmoud Hanafy🇪🇬

    The entropy per rapidity $dS/dy$ produced in central Pb-Pb ultra-relativistic nuclear collisions at LHC energies is calculated using experimentally observed identified particle spectra and source radii estimated from Hanbury Brown-Twiss (HBT) for particles, $\pi$, $k$, $p$, $\Lambda$, $\Omega$, and $\bar{\Sigma }$, and $\pi$, $k$, $p$, $\Lambda$ and $K_s^0$ at $\sqrt{s}$ $=2.76$ and $5.02$ TeV, respectively. Artificial neural network (ANN) simulation model is used to estimate the entropy per rapidity $dS/dy$ at the considered energies. The simulation results are compared with equivalent experimental data, and good agreement is achieved. A mathematical equation describes experimental data is obtained. Extrapolating the transverse momentum spectra at $p_T$ $=0$ is required to calculate $dS/dy$ thus we use two different fitting functions, Tsallis distribution and the Hadron Resonance Gas (HRG) model. The success of ANN model to describe the experimental measurements will imply further prediction for the entropy per rapidity in the absence of the experiment.

    hep-phCPC(2022)·4 citations
14. 14*

    Reducing the O(3) model as an effective field theory

    Sven Bjarke Gudnason🇨🇳 · Muneto Nitta🇯🇵

    We consider the O(3) or CP(1) nonlinear sigma model as an effective field theory in a derivative expansion, with the most general Lagrangian that obeys O(3), parity and Lorentz symmetry. We work out the complete list of possible operators (terms) in the Lagrangian and eliminate as many as possible using integrations by parts. We further show at the four-derivative level, that the theory can be shown to avoid the Ostrogradsky instability, because the dependence on the d'Alembertian operator or so-called box, can be eliminated by a field redefinition. Going to the six-derivative order in the derivative expansion, we show that this can no longer be done, unless we are willing to sacrifice Lorentz invariance. By doing so, we can eliminate all dependence on double time derivatives and hence the Ostrogradsky instability or ghost, however, we unveil a remaining dynamical instability that takes the form either as a spiral instability or a runaway instability and estimate the critical field norm, at which the instability sets off.

    hep-phhep-thmath-phmath.MPJHEP(2022)·1 citation
15. 15*

    Long-lived heavy neutral leptons at the LHC: four-fermion single-$N_R$ operators

    Rebeca Beltrán🇪🇸 · Giovanna Cottin🇨🇱 · Juan Carlos Helo🇨🇱 · Martin Hirsch🇪🇸 · Arsenii Titov🇪🇸 · Zeren Simon Wang🇹🇼

    Interest in searches for heavy neutral leptons (HNLs) at the LHC has increased considerably in the past few years. In the minimal scenario, HNLs are produced and decay via their mixing with active neutrinos in the Standard Model (SM) spectrum. However, many SM extensions with HNLs have been discussed in the literature, which sometimes change expectations for LHC sensitivities drastically. In the $N_R$SMEFT, one extends the SM effective field theory with operators including SM singlet fermions, which allows to study HNL phenomenology in a "model independent" way. In this paper, we study the sensitivity of ATLAS to HNLs in the $N_R$SMEFT for four-fermion operators with a single HNL. These operators might dominate both production and decay of HNLs, and we find that new physics scales in excess of 20 TeV could be probed at the high-luminosity LHC.

    hep-phhep-exJHEP(2022)·43 citations
16. 16*

    Lund jet plane for Higgs tagging

    Charanjit K. Khosa🇮🇹

    We study the boosted Higgs tagging using the Lund jet plane. The convolutional neural network is used for the Lund images data set to classify hadronically decaying Higgs from the QCD background. We consider $H\to b\bar{b}$ and $H\to gg$ decay for moderate and high Higgs transverse momentum and compare the performance with the cut based approach using the jet color ring observable. The approach using Lund plane images provides good tagging efficiency for all the cases.

    hep-phSciPost Phys.Proc.(2022)·3 citations
17. 17*

    Hadroproduction of four top quarks in the POWHEG BOX

    Tomáš Ježo🇩🇪 · Manfred Kraus🇺🇸

    We present a new Monte Carlo event generator for the hadronic production of four top quarks in the POWHEG BOX framework. Besides the dominant next-to-leading order QCD corrections at $\mathcal{O}({\alpha }_s^5)$ we also include all subleading electroweak productions channels at leading-order accuracy. We validate our theoretical predictions by comparing to parton-shower matched predictions obtained within the MC@NLO framework for stable top quarks. Furthermore, we investigate in detail the various sources of theoretical uncertainties. Finally, we investigate a single lepton plus jets signature to study for the first time the impact of the electroweak production modes as well as spin-correlation effects at the fiducial level.

    hep-phPRD(2022)·37 citations
18. 18*

    Singlet fermion dark matter and Dirac neutrinos from Peccei-Quinn symmetry

    Cristian D. R. Carvajal🇨🇴 · Robinson Longas🇨🇴 · Oscar Rodríguez🇨🇴 · Óscar Zapata🇨🇴

    The Peccei-Quinn (PQ) mechanism not only acts as an explanation for the absence of strong CP violation but also can play a main role in the solution to other open questions in particle physics and cosmology. Here we consider a model that identifies the PQ symmetry as a common thread in the solution to the strong CP problem, the generation of radiative Dirac neutrino masses and the origin of a multicomponent dark sector. Specifically, scotogenic neutrino masses arise at one loop level with the lightest fermionic mediator field acting as the second dark matter (DM) candidate thanks to the residual $Z_2$ symmetry resulting from the PQ symmetry breaking. We perform a phenomenological analysis addressing the constraints coming from the direct searches of DM, neutrino oscillation data and charged lepton flavor violating (LFV) processes. We find that the model can be partially probed in future facilities searching for WIMPs and axions, and accommodates rates for rare leptonic decays that are within the expected sensitivity of upcoming LFV experiments.

    hep-phPRD(2022)·7 citations
19. 19*

    The role of leptonic CPV phases in cLFV observables

    J. Kriewald🇫🇷 · A. Abada🇫🇷 · A. M. Teixeira🇫🇷

    In models where the Standard Model is extended by Majorana fermions, interference effects due to the presence of CP violating phases have been shown to play a crucial role in lepton number violating processes. However, important effects can also arise in lepton number conserving, but charged lepton flavour violating (cLFV) transitions and decays. Here we show that the presence of CP violating (Dirac and Majorana) phases can have a striking impact for the predicted rates of cLFV observables. We explore the interference effects in several cLFV observables, carrying for the first time a thorough analysis of the different observables and the implications for future observation. We discuss how the presence of leptonic CP violating phases might lead to a loss of correlation between observables (typically present in simple SM extensions via heavy sterile fermions), or even to the suppression of certain channels; these effects can be interpreted as suggestive of non-vanishing phases.

    hep-phJ.Phys.Conf.Ser.(2021)·1 citation
20. 20*

    Reducing negative weights in Monte Carlo event generation with Sherpa

    Katharina Danziger🇩🇪 · Stefan Höche🇺🇸 · Frank Siegert🇩🇪

    An increase in theoretical precision of Monte Carlo event generators is typically accompanied by an increased need for computational resources. One major obstacle are negative weighted events, which appear in Monte Carlo simulations with higher perturbative accuracy. While they can be handled somewhat easily in fixed-order calculations, they are a major concern for particle level event simulations. In this article, the origin of negative weights in the S-MC@NLO method is reviewed and mechanisms to reduce the negative weight fraction in simulations with the Sherpa event generator are presented, with a focus on V+jets and tt+jets simulations.

    hep-phhep-ex45 citations
21. 21*

    Ground state heavy tetraquark production in heavy quark fragmentation

    S.Mohammad Moosavi Nejad🇮🇷 · Nahid Amiri🇮🇷

    During recent years, the study of exotic hadrons including tetraquarks and pentaquarks has attracted a lot of interests and more studies are in progress experimentally and theoretically. It is well-known that at sufficiently large transverse momentum the dominant production mechanism for standard heavy hadrons (mesons/baryons) is actually the fragmentation so that the same mechanism is also proposed for the production of heavy exotic hadrons. This work is the first attempt to study the direct fragmentation of a heavy quark into ground state heavy tetraquarks in leading order of perturbative QCD. In this regard, we will present an exact analytical expression for the fragmentation production of neutral hidden flavor tetraquarks $(Qq\bar{Q}\bar{q})$ which includes most of the kinematical and dynamical properties of the process.

    hep-phPRD(2022)·25 citations
22. 22*

    Prediction of new $T_{cc}$ states of $D^{\ast }{D}^{\ast }$ and $D_s^{\ast }{D}^{\ast }$ molecular nature

    L. R. Dai🇨🇳 · R. Molina🇪🇸 · E. Oset🇪🇸

    We extend the theoretical framework used of describe the $T_{cc}$ state as a molecular state of $D^{\ast }D$ and make predictions for the $D^{\ast }{D}^{\ast }$ and $D_s^{\ast }{D}^{\ast }$ systems, finding that they lead to bound states only in the $J^P=1^{+}$ channel. Using input needed to describe the $T_{cc}$ state, basically one parameter to regularize the loops of the Bethe-Salpeter equation, we find bound states with bindings of the order of the MeV and similar widths for $D^{\ast }{D}^{\ast }$ system, while the $D_s^{\ast }{D}^{\ast }$ system develops a strong cusp around threshold.

    hep-phPRD(2022)·56 citations
23. 23*

    A novel event generator for the automated simulation of neutrino scattering

    Joshua Isaacson🇺🇸 · Stefan Höche🇺🇸 · Diego Lopez Gutierrez🇺🇸 · Noemi Rocco🇺🇸

    An event generation framework is presented that enables the automatic simulation of events for next-generation neutrino experiments in the Standard Model or extensions thereof. The new generator combines the calculation of the leptonic current based on an automated matrix element generator, and the computation of the hadronic current based on a state-of-the-art nuclear physics model. The approach is validated in Standard-Model simulations for electron scattering and neutrino scattering. Furthermore, the first fully-differential neutrino trident production results are shown in the quasielastic region.

    hep-phhep-exnucl-thPRD(2022)·19 citations
24. 24*

    Precision predictions for scalar leptoquark pair production at the LHC

    Christoph Borschensky🇩🇪 · Benjamin Fuks🇫🇷 · Anna Kulesza🇩🇪 · Daniel Schwartländer🇩🇪

    We present precision predictions for scalar leptoquark pair production at the LHC. Apart from QCD contributions, included are the lepton $t$-channel exchange diagrams relevant in the light of the recent $B$-flavour anomalies. All contributions are evaluated at next-to-leading order in QCD and improved by resummation, in the threshold regime, of the corrections from soft-gluon radiation at the next-to-next-to-leading-logarithmic accuracy. All corrections are found equally relevant. Furthermore, the impact of different sets of parton distribution functions is discussed. These predictions constitute the most precise leptoquark cross section calculations available to date and are necessary for the best exploitation of leptoquark LHC searches.

    hep-phPoS(2022)·9 citations
25. 25*

    Decomposition of $d=9$ short-range $0\nu \beta \beta$ decay operators at one-loop level

    Ping-Tao Chen🇨🇳 · Gui-Jun Ding🇨🇳 · Chang-Yuan Yao🇨🇳

    We perform a systematical study of the dimension-9 short-range $0\nu \beta \beta$ decay operators at one-loop level. There are only six genuine topologies which generate eight diagrams, and the recipe to identify the possible one-loop realizations of the $0\nu \beta \beta$ decay operators is sketched. Certain hypercharge assignments are excluded by the absence of tree-level diagrams in a genuine one-loop model. The mediators of each decomposition can generate Majorana neutrino masses which are discussed up to two-loop level. We present an example of $0\nu \beta \beta$ decay model in which the neutrino masses are generated at two-loop level, and the short-range contribution can be comparable with the mass mechanism in some region of parameter space.

    hep-phJHEP(2021)·12 citations
26. 26*

    Review of opportunities for new long-lived particle triggers in Run 3 of the Large Hadron Collider

    Juliette Alimena🇨🇭 · James Beacham🇺🇸 · Freya Blekman🇩🇪 · Adrián Casais Vidal🇪🇸 · Xabier Cid Vidal🇪🇸 · Matthew Citron🇺🇸 · David Curtin🇨🇦 · Albert De Roeck🇨🇭 · Nishita Desai🇮🇳 · Karri Folan Di Petrillo🇺🇸 · Yuri Gershtein🇺🇸 · Louis Henry🇪🇸 and 66 other authors

    Long-lived particles (LLPs) are highly motivated signals of physics Beyond the Standard Model (BSM) with great discovery potential and unique experimental challenges. The LLP search programme made great advances during Run 2 of the Large Hadron Collider (LHC), but many important regions of signal space remain unexplored. Dedicated triggers are crucial to improve the potential of LLP searches, and their development and expansion is necessary for the full exploitation of the new data. The public discussion of triggers has therefore been a relevant theme in the recent LLP literature, in the meetings of the LLP@LHC Community workshop and in the respective experiments. This paper documents the ideas collected during talks and discussions at these Workshops, benefiting as well from the ideas under development by the trigger community within the experimental collaborations. We summarise the theoretical motivations of various LLP scenarios leading to highly elusive signals, reviewing concrete ideas for triggers that could greatly extend the reach of the LHC experiments. We thus expect this document to encourage further thinking for both the phenomenological and experimental communities, as a stepping stone to further develop the LLP@LHC physics programme.

    ↳ hep-exhep-phhep-th48 citations
27. 27*

    QCD thermodynamics at non-zero isospin asymmetry

    Bastian B. Brandt🇩🇪 · Francesca Cuteri🇩🇪 · Gergely Endrodi🇩🇪

    We study the thermodynamic properties of QCD at nonzero isospin chemical potential using improved staggered quarks at physical quark masses. In particular, we discuss the determination of the equation of state at zero and nonzero temperatures and show results. Using the results for the isospin density $n_I$, we also determine the phase diagram in the $(n_I,T)$-plane.

    ↳ hep-lathep-phnucl-thPoS(2022)·12 citations
28. 28*

    Radiatively stable ghost and tachyon freedom in Metric Affine Gravity

    Carlo Marzo🇪🇪

    We report the existence of a ghost- and tachyon-free sector in metric-affine theories of gravity, that is invariant under diffeomorphism and a particular abelian symmetry. In contrast with many studied cases in the literature, the constraints for unitarity and causality are granted by non-accidental symmetries and do not ask for further tuning, whose fate under renormalization would be unclear. Unsurprisingly, the minimal model is massless. We find that a mechanism to provide mass is accommodated by a simple Stueckelberg extension of metric-affine gravity involving the non-metricity tensor. A non-trivial result is that also such an extension describes a ghost- and tachyon-free dynamic stabilized by the same abelian symmetry. The resulting spectrum of the collective rank-3, rank-2, and rank-0 Lagrangian is investigated with the operators recently computed in the literature.

    ↳ hep-thhep-phPRD(2022)·51 citations
29. 29*

    Standardizing Dainotti-correlated gamma-ray bursts, and using them with standardized Amati-correlated gamma-ray bursts to constrain cosmological model parameters

    Shulei Cao🇺🇸 · Narayan Khadka🇺🇸 · Bharat Ratra🇺🇸

    We show that each of the three Dainotti-correlated gamma-ray burst (GRB) data sets recently compiled by Wang et al. and Hu et al., that together probe the redshift range $0.35\le z\le 5.91$, obey cosmological-model-independent Dainotti correlation relations and so are standardizable. We use these GRB data in conjunction with the best currently-available Amati-correlated GRB data, that probe $0.3399\le z\le 8.2$, to constrain cosmological model parameters. The resulting cosmological constraints are weak, providing lower limits on the non-relativistic matter density parameter, mildly favoring non-zero spatial curvature, and largely consistent with currently accelerated cosmological expansion as well as with constraints determined from better-established data.

    ↳ astro-ph.COgr-qchep-phhep-thMNRAS(2022)·77 citations
30. 30*

    Nonlinear Klein-Gordon equation and the Bose-Einstein condensation

    E. Megias🇪🇸 · M.J. Teixeira🇧🇷 · V.S. Timóteo🇧🇷 · A. Deppman🇧🇷

    The interest in the Klein-Gordon equation with different potentials has increased in recent years due to its possible applications in Cosmology, Hadron Physics and High-Energy Physics. In this work we investigate the solutions of the Klein-Gordon equation for bosons under the influence of an external potential by using the Feshbach-Villars method. We present detailed results for two cases: the Coulombic potential and the harmonic potential. For the latter case, we studied the effects of self-interacting particles by adopting a mean-field approach. We show that our results converge smoothly to the solution of the Schrödinger equation for the same systems as the relativistic effects diminish.

    ↳ cond-mat.quant-gashep-phnucl-thEur.Phys.J.Plus(2022)·1 citation
31. 31*

    $m_c$ (and $m_b$) from lattice QCD

    Andrew T. Lytle🇺🇸

    Quark mass determinations based on lattice QCD simulations have continued to make strides in recent years. Here I review that progress with a focus on developments computing the charm (and bottom) quark masses since the 2015 edition of CHARM. These advances have resulted in groups now quoting (sub-)percent-level precision for these quantities, and, importantly, using a variety of techniques subject to differing systematic uncertainties. Improvements to quantify the effects of QED are also now being included. I will highlight three of the strategies being used to determine $m_c$ at this level of precision.

    ↳ hep-lathep-phPoS(2021)·1 citation
32. 32*

    Gravitational Collapse in the Post-Inflationary Universe

    Benedikt Eggemeier🇩🇪 · Bodo Schwabe🇩🇪 · Jens C. Niemeyer🇩🇪 · Richard Easther🇳🇿

    The Universe may pass through an effectively matter-dominated epoch between inflation and Big Bang Nucleosynthesis during which gravitationally bound structures can form on subhorizon scales. In particular, the inflaton field can collapse into inflaton halos, forming "large scale" structure in the very early universe. We combine N-body simulations with high-resolution zoom-in regions in which the non-relativistic Schrödinger-Poisson equations are used to resolve the detailed, wave-like structure of inflaton halos. Solitonic cores form inside them, matching structure formation simulations with axion-like particles in the late-time universe. We denote these objects \textit{inflaton stars}, by analogy with boson stars. Based on a semi-analytic formalism we compute their overall mass distribution which shows that some regions will reach overdensities of $10^{15}$ if the early matter-dominated epoch lasts for 20 $e$-folds. The radii of the most massive inflaton stars can shrink below the Schwarzschild radius, suggesting that they could form primordial black holes prior to thermalization.

    ↳ astro-ph.COhep-phPRD(2022)·46 citations
33. 33*

    Prospects in the search for a new light $Z^{\prime }$ boson with the NA64$\mu$ experiment at the CERN SPS

    H. Sieber🇨🇭 · D. Banerjee🇨🇭 · P. Crivelli🇨🇭 · E. Depero🇨🇭 · S. N. Gninenko🇷🇺 · D. V. Kirpichnikov🇷🇺 · M. M. Kirsanov🇷🇺 · V. Poliakov🇷🇺 · L. Molina Bueno🇨🇭

    A light $Z^{\prime }$ vector boson coupled to the second and third lepton generations through $L_{\mu }-L_{\tau }$ current with mass below 200 MeV provides a very viable explanation in terms of new physics to the recently confirmed $(g-2{)}_{\mu }$ anomaly. This boson can be produced in the bremsstrahlung reaction $\mu N\to \mu N{Z}^{\prime }$ after a high energy muon beam collides with a target. NA64$\mu$ is a fixed-target experiment using a 160 GeV muon beam from the CERN Super Proton Synchrotron accelerator looking for the $Z^{\prime }$ production and its subsequent decays, $Z^{\prime }\to invisible$. In this paper, we present the study of the NA64$\mu$ sensitivity to search for such a $Z^{\prime }$. This includes a realistic beam simulation, the detailed detectors description and a discussion about the main potential background sources. A pilot run is scheduled in order to validate the simulation results. If those are confirmed, NA64$\mu$ will be able to explore all the remaining phase space which could provide an explanation for the $g-2$ muon anomaly.

    ↳ hep-exhep-phPRD(2022)·62 citations
34. 34*

    Application of Lorentzian CFT Principal Series Representation to Near Forward Scattering

    Pulkit Agarwal🇸🇬 · Richard C. Brower🇺🇸 · Timothy G. Raben🇺🇸 · Chung-I Tan🇺🇸

    We present a discussion on recent progress in high energy diffraction from the perspective of AdS/CFT, through which a unified treatment for both perturbative and nonperturbative Pomeron emerges. By working with Unitary Irreducible Representation of Conformal group, a frame is provided in extending AdS/CFT to both forward and nearforward scattering. We present an analysis involving an exact solution to conformal blocks in Minkowski CFT and discuss possible applications. Phenomenological applications can range from forward scattering to DIS/DVCS/TMD at LHC energies and beyond.

    ↳ hep-thhep-phSciPost Phys.Proc.(2022)·4 citations
35. 35*

    Towards Color-Kinematics Duality in Generic Spacetimes

    Allic Sivaramakrishnan🇺🇸

    In this note, we study color-kinematics duality in generic spacetimes. We work with a contact representation for on shell correlators. The position-space integrand is encoded by enumerated differential operators. This setup generalizes certain features of S-matrix kinematics to curved space. Differences between flat and curved space are captured by commutators. We study the nonlinear sigma model at four points as an explicit example and find that color-kinematics duality holds in generic spacetimes. We illustrate our approach in the AdS transition amplitude, a type of on shell correlation function. We find a double copy procedure at four points that connects the nonlinear sigma model, the biadjoint scalar theory, and the special Galileon theory.

    ↳ hep-thhep-phmath-phmath.MPJHEP(2022)·45 citations
36. 36*

    Information Geometry and Holographic Correlators

    Hardik Bohra🇺🇸 · Ashish Kakkar🇺🇸 · Allic Sivaramakrishnan🇺🇸

    We explore perturbative corrections to quantum information geometry. In particular, we study a Bures information metric naturally associated with the correlation functions of a conformal field theory. We compute the metric of holographic four-point functions and include corrections generated by tree Witten diagrams in the bulk. In this setting, we translate properties of correlators into the language of information geometry. Cross terms in the information metric encode non-identity operators in the OPE. We find that the information metric is asymptotically AdS. Finally, we discuss an information metric for transition amplitudes.

    ↳ hep-thcond-mat.str-elhep-phquant-phJHEP(2022)·4 citations
37. 37*

    C${}^3$: A "Cool" Route to the Higgs Boson and Beyond

    Mei Bai🇺🇸 · Tim Barklow🇺🇸 · Rainer Bartoldus🇺🇸 · Martin Breidenbach🇺🇸 · Philippe Grenier🇺🇸 · Zhirong Huang🇺🇸 · Michael Kagan🇺🇸 · John Lewellen🇺🇸 · Zenghai Li🇺🇸 · Thomas W. Markiewicz🇺🇸 · Emilio A. Nanni🇺🇸 · Mamdouh Nasr🇺🇸 and 14 other authors

    We present a proposal for a cold copper distributed coupling accelerator that can provide a rapid route to precision Higgs physics with a compact 8 km footprint. This proposal is based on recent advances that increase the efficiency and operating gradient of a normal conducting accelerator. This technology also provides an $e^{+}{e}^{-}$ collider path to physics at multi-TeV energies. In this article, we describe our vision for this technology and the near-term R&D program needed to pursue it.

    ↳ hep-exhep-phphysics.acc-ph100 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.