Thu·Nov 25, 2021Thursday·November 25, 2021

1. 01*

   Flavor Violating Axions in the Early Universe

   Francesco D'Eramo🇮🇹 · Seokhoon Yun🇮🇹

   Flavor violating axion couplings can be in action before recombination, and they can fill the early universe with an additional radiation component. Working within a model-independent framework, we consider an effective field theory for the axion field and quantify axion production. Current cosmological data exclude already a fraction of the available parameter space, and the bounds will improve significantly with future CMB-S4 surveys. Remarkably, we find that future cosmological bounds will be comparable or even stronger than the ones obtained in our terrestrial laboratories.

   hep-phastro-ph.COPRD(2022)·50 citations
2. 02*

   Event-based anomaly detection for new physics searches at the LHC using machine learning

   S.V. Chekanov🇺🇸 · W. Hopkins🇺🇸

   This paper discusses model-agnostic searches for new physics at the Large Hadron Collider (LHC) using anomaly-detection techniques for the identification of event signatures that deviate from the Standard Model (SM). We investigate anomaly detection in the context of machine-learning approaches using autoencoders, and illustrate expected shapes of invariant masses in the outlier region using Monte Carlo simulations. Challenges and conceptual limitations of this approach are discussed.

   hep-phUniverse(2022)·23 citations
3. 03*

   Event-level variables for semivisible jets using anomalous jet tagging

   Hugues Beauchesne🇹🇼 · Giovanni Grilli di Cortona🇮🇹

   Semivisible jets are a characteristic signature of many confining dark sectors and consist of jets of visible hadrons intermixed with invisible stable particles. Since their initial proposal, considerable progress has been made in developing techniques for tagging anomalous jets. In this paper, we show that the ability to tag semivisible jets can be used to define new event-level variables which use generally ignored kinematic information and can considerably increase our ability to discover dark confining sectors. In practice, our best results are obtained by using the coefficients of the decomposition of the missing transverse momentum in terms of the transverse momenta of the jets tagged as anomalous. A benchmark scenario is introduced and the increase in significance due to these new variables is studied over some of its parameter space.

   hep-ph8 citations
4. 04*

   The muon $g-2$ in an Aligned 2-Higgs Doublet Model with Right-Handed Neutrinos

   Luigi Delle Rose🇪🇸 · Shaaban Khalil🇪🇬 · Stefano Moretti🇬🇧

   In this note, we show how one can attribute the anomaly currently present in the measurement of the anomalous magnetic moment of the muon ($a_{\mu }$) to the presence of an underlying Aligned 2-Higgs Doublet Model (A2HDM) with Right-Handed (RH) neutrinos, ${\nu }_R$. The effects of the latter scenario are driven by one and two-loop topologies wherein a very light CP-odd neutral Higgs state ($A$) contributes significantly to $a_{\mu }$. Over the region of parameter space of our new physics model which explains the aforementioned anomaly, also consistent with the most recent measurements of the electron anomalous magnetic moment ($a_e$), wherein the charged Higgs state $H^{\pm }$ plays a similar role, we predict an almost background-free hallmark signature of it, due to $H^{\pm }A$ production followed by Higgs boson decays yielding multi-$\tau$ final states, which can be already be searched for at the Large Hadron Collider (LHC).

   hep-ph2 citations
5. 05*

   Searching for $H^{\pm }\to W^{\pm }+4\gamma$ signals in the 2HDM Type-I at the LHC

   Yan Wang🇨🇳 · A. Arhrib🇲🇦 · R. Benbrik🇲🇦 · M. Krab🇲🇦 · B. Manaut🇲🇦 · S. Moretti🇬🇧 · Qi-Shu Yan🇨🇳

   We analyze a new signature of a charged Higgs boson in the Type-I realization of the 2-Higgs Doublet Model (2HDM), where the mass of the charged Higgs boson satisfies the condition $M_{H^{\pm }}<M_t+M_b$ and the theoretical parameter space is consistent with the latest experimental constraints from Large Hadron Collider (LHC) and other direct as well as indirect searches. In the surviving regions, it is found that the bosonic decay mode of a charged Higgs boson is dominated by $H^{\pm }\to W^{\pm \ast }h$. At the same time, the light neutral Higgs boson $h$ dominantly decays into two photons. We thus find that the production process $pp\to H^{\pm }h\to W^{\pm \ast }hh\to l^{\pm }\nu +4\gamma$ is almost background free. Since the $W^{\pm }$ could be either off-shell or on-shell, furthering a previous phenomenological analysis, we examine closely detector effects onto the above signature and demonstrate that it is indeed promising to study it at the LHC with both $\sqrt{s}=13$ TeV and $\sqrt{s}=14$ TeV, assuming an integrated luminosity of 300 $f{b}^{-1}$.

   hep-ph4 citations
6. 06*

   Subprocesses $\rho (770,1450)\to K\bar{K}$ for the three-body hadronic $D$ meson decays

   Wen-Fei Wang🇨🇳

   We construct the theoretical framework for quasi-two-body $D$ meson decays with the help of pion and kaon electromagnetic form factors, and with which we study the contributions of the subprocesses $\rho (770,1450)\to K\bar{K}$ for the three-body $D$ decays within the flavour $SU(3)$ symmetry. Because of the limitations imposed by phase space and strong coupling, the contributions for kaon pair from the virtual bound state $\rho (770)$ are channel-dependent and generally small for the concerned three-body $D$ decays. But some quasi-two-body processes could still be observed in the Dalitz plot analyses for related decays, such as $D^0\to K^{-}\rho (770{)}^{+}\to K^{-}{K}^{+}{K}_S^0$ and $D^{+}\to K_S^0\rho (770{)}^{+}\to K_S^0{K}^{+}{K}_S^0$, they are predicted to have the branching fractions $\mathcal{B}=(0.82\pm 0.04)\times 10^{-4}$ and $\mathcal{B}=0.47_{-0.03}^{+0.05}\times 10^{-4}$, which are $(1.86\pm 0.16)\%$ and $(1.84_{-0.16}^{+0.21})\%$, respectively, of the total branching fractions for the corresponding three-body $D$ decays. We find in this work that the normal subprocesses like $\rho (1450{)}^{+}\to {\pi }^{+}{\pi }^0$ or $\rho (1450{)}^{+}\to K^{+}{\bar{K}}^0$, which are bound by the masses of decaying initial states, will provide virtual contributions in some special decays.

   hep-phhep-exPRD(2021)·8 citations
7. 07*

   Neutrinos and their interactions

   M. Sajjad Athar🇮🇳 · S. K. Singh🇮🇳

   We present a short overview of the importance of the study of "Neutrino Interactions in the Intermediate and High Energy Region", with an introduction to the neutrinos and a very brief description about the collection of invited articles.

   hep-phnucl-thEur.Phys.J.ST(2021)·5 citations
8. 08*

   The three-loop polarized singlet anomalous dimensions from off-shell operator matrix elements

   J. Blümlein🇩🇪 · P. Marquard🇩🇪 · C. Schneider🇦🇹 · K. Schönwald🇩🇪

   Future high luminosity polarized deep--inelastic scattering experiments will improve both the knowledge of the spin sub--structure of the nucleons and contribute further to the precision determination of the strong coupling constant, as well as, reveal currently yet unknown higher twist contributions in the polarized sector. For all these tasks to be performed, it is necessary to know the QCD leading twist scaling violations of the measured structure functions. Here an important ingredient consists in the polarized singlet anomalous dimensions and splitting functions in QCD. We recalculate these quantities to three--loop order in the M--scheme by using the traditional method of space--like off--shell massless operator matrix elements, being a gauge--dependent framework. Here one obtains the anomalous dimensions without referring to gravitational currents, needed when calculating them using the forward Compton amplitude. We also calculate the non--singlet splitting function $\Delta P_{\mathrm{qq}}^{(2),\mathrm{s},\mathrm{NS}}$ and compare the final results to the literature, also including predictions for the region of small values of Bjorken $x$.

   hep-phhep-exhep-thJHEP(2022)·82 citations
9. 09*

   Improved calculation of the ${\gamma }^{\ast }\gamma \to \pi$ process at low $Q^2$ using LCSR's and renormalization-group summation

   Sergey Mikhailov🇷🇺 · Alexandr Pimikov🇷🇺 · N. G. Stefanis🇩🇪

   We study two versions of lightcone sum rules to calculate the ${\gamma }^{\ast }\gamma \to {\pi }^0$ transition form factor (TFF) within QCD. While the standard version is based on fixed-order perturbation theory by means of a power-series expansion in the strong coupling, the new method incorporates radiative corrections by renormalization-group summation and generates an expansion within a generalized fractional analytic perturbation theory involving only analytic couplings. Using this scheme, we determine the relative nonperturbative parameters and the first two Gegenbauer coefficients of the pion distribution amplitude (DA) to obtain TFF predictions in good agreement with the preliminary BESIII data, while the best-fit pion DA satisfies the most recent lattice constraints on the second moment of the pion DA at the three-loop level.

   hep-phhep-exEPJ Web Conf.(2022)·4 citations
10. 10*

    Cross-Sections for $\text{t}\bar{\text{t}}\text{H}$ production with the Top Quark $\overline{\text{MS}}$ Mass

    Maria Aldaya Martin🇩🇪 · Sven-Olaf Moch🇩🇪 · Andrej Saibel🇩🇪

    We study the impact of the top quark mass renormalized in the $\overline{\text{MS}}$ scheme on the $\text{t}\bar{\text{t}}\text{H}$ production cross-sections as an alternative to theory predictions with the conventionally used pole mass scheme. The differential cross-sections at next-to-leading order in perturbative QCD with stable top quarks show a moderate decrease in scale uncertainties for the $\overline{\text{MS}}$ mass renormalization scheme compared to the on-shell one. The shape of the differential distributions is not affected much, the largest differences being observed in the invariant mass distributions of the $\text{t}\bar{\text{t}}$ and the $\text{t}\bar{\text{t}}\text{H}$ systems.

    hep-phPLB(2022)·3 citations
11. 11*

    Electroweak input parameters

    Ilaria Brivio🇩🇪 · Sally Dawson🇺🇸 · Jorge de Blas🇪🇸 · Gauthier Durieux🇨🇭 · Pierre Savard (editors)🇨🇦 · Ansgar Denner🇩🇪 · Ayres Freitas🇺🇸 · Chris Hays🇬🇧 · Ben Pecjak🇬🇧 · Alessandro Vicini🇮🇹

    Different sets of electroweak input parameters are discussed for SMEFT predictions at the LHC. The {Gmu,mZ,mW} one is presently recommended.

    hep-ph52 citations
12. 12*

    Lepton Phenomenology of Stueckelberg Portal to Dark Sector

    A. Kachanovich🇩🇪 · S. Kovalenko🇨🇱 · S. Kuleshov🇨🇱 · V.E. Lyubovitskij🇩🇪 · A.S. Zhevlakov🇷🇺

    We propose an extension of the Standard Model (SM) with a $U_{A^{\prime }}(1)$ gauge invariant dark dector connected to the SM via a new portal -- the Stueckelberg portal, arising in the framework of dark photon $A^{\prime }$ mass generation via Stueckelberg mechanism. This portal opens through the effective dim=5 operators constructed from the covariant term of the auxiliary Stueckelberg scalar field $\sigma$ providing flavor non-diagonal renormalizable couplings of both $\sigma$ and $A^{\prime }$ to the SM fermions $\psi$. The Stueckelberg scalar plays a role of Goldstone boson in the generation of mass of the Dark Photon. Contrary to the conventional kinetic mixing portal, in our scenario flavor diagonal $A^{\prime }$-$\psi$ couplings are not proportional to the fermion charges and are, in general, flavor nondiagonal. These features drastically change the phenomenology of dark photon $A^{\prime }$ relaxing or avoiding some previously established experimental constraints. We focus on the phenomenology of the described scenario of the Stueckelberg portal in the lepton sector and analyze the contribution of the dark sector fields $A^{\prime }$ to the anomalous magnetic moment of muon $(g-2{)}_{\mu }$, lepton flavor violating decays $l_i\to l_k\gamma$ and $\mu -e$ conversion in nuclei. We obtain limits on the model parameters from the existing data on the corresponding observables.

    hep-phPRD(2022)·15 citations
13. 13*

    Statistical significance of the sterile-neutrino hypothesis in the context of reactor and gallium data

    Jeffrey M. Berryman🇺🇸 · Pilar Coloma🇪🇸 · Patrick Huber🇺🇸 · Thomas Schwetz🇩🇪 · Albert Zhou🇩🇪

    We evaluate the statistical significance of the 3+1 sterile-neutrino hypothesis using ${\nu }_e$ and ${\bar{\nu }}_e$ disappearance data from reactor, solar and gallium radioactive source experiments. Concerning the latter, we investigate the implications of the recent BEST results. For reactor data we focus on relative measurements independent of flux predictions. For the problem at hand, the usual ${\chi }^2$-approximation to hypothesis testing based on Wilks' theorem has been shown in the literature to be inaccurate. We therefore present results based on Monte Carlo simulations, and find that this typically reduces the significance by roughly $1\sigma$ with respect to the naïve expectation. We find no significant indication in favor of sterile-neutrino oscillations from reactor data. On the other hand, gallium data (dominated by the BEST result) show more than $5\sigma$ of evidence supporting the sterile-neutrino hypothesis, favoring oscillation parameters in agreement with constraints from reactor data. This explanation is, however, in significant tension ($\sim 3\sigma$) with solar neutrino experiments. In order to assess the robustness of the signal for gallium experiments we present a discussion of the impact of cross-section uncertainties on the results.

    hep-phhep-exnucl-exJHEP(2022)·71 citations
14. 14*

    A new Higgs effective field theory and the new no-lose theorem

    Shinya Kanemura🇯🇵 · Ryo Nagai🇯🇵

    Non-decoupling effects of heavy new particles cannot be described by the standard effective field theory with finite truncation of higher dimensional operators. We propose a new effective field theory in which non-decoupling quantum effects of new physics are correctly described. We discuss vacuum stability and perturbative unitarity in our effective field theory, and we find that the scale of new physics can be estimated if we will observe the Higgs coupling deviation via non-decoupling effects in future collider experiments.

    hep-phJHEP(2022)·24 citations
15. 15*

    Off-shell Higgs production at the LHC as a probe of the trilinear Higgs coupling

    Ulrich Haisch🇩🇪 · Gabriël Koole🇩🇪

    In the context of the Standard Model effective field theory (SMEFT) we examine the constraints on the trilinear Higgs coupling that originate from off-shell Higgs production in proton-proton collisions. Our calculation of the $gg\to h^{\ast }\to ZZ\to 4\ell$ process includes two-loop corrections to gluon-gluon-fusion Higgs production and one-loop corrections to the Higgs propagator and its decay. Employing a matrix-element based kinematic discriminant we determine the reach of LHC Run 3 and the high-luminosity option of the LHC in constraining the relevant SMEFT Wilson coefficients. We present constraints that are not only competitive with but also complementary to the projected indirect limits that one expects to obtain from inclusive measurements of single-Higgs production processes at future LHC runs.

    hep-phhep-exJHEP(2022)·26 citations
16. 16*

    Alignment function as a new kind of transverse momentum dependent functions

    I.V. Anikin🇷🇺 · L. Szymanowski🇵🇱

    We argue the existence of new $k_{\perp }$-dependent functions which can be manifested in the Drell-Yan (SIDIS)-like processes. The presented new functions resemble the well-known Boer-Mulders function associated with the quark spin asymmetry, but in contrast they are sensitive to the transverse motion of partons inside the hadron due to the collective alignment of quark spin vectors.

    hep-phEPJA(2022)·5 citations
17. 17*

    A combination of the neutrino trimaximal mixings and mu-tau reflection symmetry in the type-I seesaw model

    Zhen-hua Zhao🇨🇳

    In this paper, we make an attempt to combine the neutrino trimaximal (TM1 and TM2) mixings and $\mu$-$\tau$ reflection symmetry in the type-I seesaw model. Such a scenario is highly restrictive and predictive: in addition to three right-handed neutrino masses, there are only five real parameters; all the lepton flavor mixing parameters except for ${\theta }_{13}^{}$ will be predicted. The relations between the model parameters and the measurable neutrino parameters will be derived. The implications of this scenario for leptogenesis will be explored in detail. A further reduction of this scenario to the more restrictive and predictive minimal seesaw model with only two right-handed neutrinos will also be considered. In addition, we will also discuss a possible approach to get the desired mass matrices and study the compatibility of the trimaximal $\mu$-$\tau$ reflection symmetry with texture zeros.

    hep-phEPJC(2022)·30 citations
18. 18*

    On-shell Z boson production through $\mathcal{O}(\alpha {\alpha }_s)$

    Roberto Bonciani🇮🇹 · Federico Buccioni🇬🇧 · Narayan Rana🇮🇹 · Alessandro Vicini🇮🇹

    The analytical expressions of the mixed QCD-EW corrections to on-shell Z boson inclusive production cross section at hadron colliders are presented, together with computational details. The results are given in terms of polylogarithmic functions and elliptic integrals. The impact on the prediction of the Z boson production total cross section is discussed, comparing different proton parton density sets.

    hep-phhep-exJHEP(2022)·29 citations
19. 19*

    Pseudo and quasi gluon PDF in the BFKL approximation

    Giovanni Antonio Chirilli🇩🇪

    I study the behavior of the gauge-invariant gluon bi-local operator with space-like separation at large longitudinal distances. Performing the Fourier transform, I also calculate the behavior of the pseudo and quasi gluon PDF at low Bjorken $x$ and compare it with the leading and next-to-leading twist approximation. I show that the pseudo-PDF and quasi-PDF are very different in this regime and that the higher twist corrections of the quasi-PDF come in not as inverse powers of $P$ but as inverse powers of $x_{B}P$.

    hep-phJHEP(2022)·8 citations
20. 20*

    The Strange Physics of Dark Baryons

    Gonzalo Alonso-Álvarez🇨🇦 · Gilly Elor🇩🇪 · Miguel Escudero🇩🇪 · Bartosz Fornal🇺🇸 · Benjamín Grinstein🇺🇸 · Jorge Martin Camalich🇪🇸

    Dark sector particles at the GeV scale carrying baryon number provide an attractive framework for understanding the origin of dark matter and the matter-antimatter asymmetry of the universe. We demonstrate that dark decays of hadronic states containing strange quarks -- hyperons -- offer excellent prospects for discovering such dark baryons. Building up on novel calculations of the matrix elements relevant for hyperon dark decays, and in view of various collider, flavor, and astrophysical constraints, we determine the expected rates at hyperon factories like BESIII and LHCb. We also highlight the interesting theoretical connections of hyperon dark decays to the neutron lifetime anomaly and Mesogenesis.

    hep-phastro-ph.COhep-exPRD(2022)·64 citations
21. 21*

    Audible Axions with a Booster: Stochastic Gravitational Waves from Rotating ALPs

    Eric Madge🇮🇱 · Wolfram Ratzinger🇩🇪 · Daniel Schmitt🇩🇪 · Pedro Schwaller🇩🇪

    Gravitational waves provide a novel way to probe axions or axion-like particles coupled to a dark photon field, even in the absence of couplings to Standard Model particles. In the conventional misalignment mechanism, the generation of an observable stochastic gravitational wave background, however, requires large axion decay constants. We here investigate the gravitational wave signal generated within the kinetic misalignment scenario, where the axion is assumed to have a large initial velocity. Its kinetic energy then provides a sufficiently high energy budget to generate a detectable gravitational wave signal also at lower values of the decay constant. We obtain an analytic estimate as well as perform numerical simulations of the corresponding gravitational wave signal, and evaluate its detectability at current and future gravitational wave observatories. We further present the corresponding projected constraints on the parameter space of the model, along with the parameter regions in which the dark photon or axion constitute dark matter, or in which the baryon asymmetry of the Universe is generated via the axiogenesis mechanism. Finally we compute the GW production from the fragmentation of rotating axions, which is however difficult to observe experimentally.

    hep-phastro-ph.COSciPost Phys.(2022)·44 citations
22. 22*

    Mounting Evidence for the Violation of Lepton Flavor Universality

    Andreas Crivellin🇨🇭 · Martin Hoferichter🇨🇭

    The Standard Model (SM) of particle physics was finalized in its current form in the mid-1970s, and has been extensively tested and confirmed ever since, with the discovery of the Higgs boson in 2012 being the last missing piece. While no new particles have been directly discovered at the Large Hadron Collider (LHC) at CERN so far, precision observables sensitive to quantum effects of new particles have accumulated intriguing hints for physics beyond the SM. All these anomalies can be interpreted from the point of view of lepton flavor universality, i.e., as hints that electrons, muons, and tau leptons differ much more than predicted by the SM. These tensions can be explained by postulating the existence of new exotic particles. Future measurements will be able to conclusively test this hypothesis, potentially providing long-awaited evidence how the SM needs to be extended at high energies.

    hep-phhep-exhep-latnucl-ex+1Science(2021)·47 citations
23. 23*

    Sp(4) gauge theories and beyond the standard model physics

    Biagio Lucini🇬🇧 · Ed Bennett🇬🇧 · Jack Holligan🇬🇧 · Deog Ki Hong🇰🇷 · Ho Hsiao🇹🇼 · Jong-Wan Lee🇰🇷 · C.-J. David Lin🇹🇼 · Michele Mesiti🇬🇧 · Maurizio Piai🇬🇧 · Davide Vadacchino🇮🇪

    We review numerical results for models with gauge group Sp(2N), discussing the glueball spectrum in the large-N limit, the quenched meson spectrum of Sp(4) with Dirac fermions in the fundamental and in the antisymmetric representation and the Sp(4) gauge model with two dynamical Dirac flavours. We also present preliminary results for the meson spectrum in the Sp(4) gauge theory with two fundamental and three antisymmetric Dirac flavours. The main motivation of our programme is to test whether this latter model is viable as a realisation of Higgs compositeness via the pseudo Nambu Goldstone mechanism and at the same time can provide partial top compositeness. In this respect, we report and briefly discuss preliminary results for the mass of the composite baryon made with two fundamental and one antisymmetric fermion (chimera baryon), whose physical properties are highly constrained if partial top compositeness is at work. Our investigation shows that a fully non-perturbative study of Higgs compositeness and partial top compositeness in Sp(4) is within reach with our current lattice methodology.

    ↳ hep-lathep-phhep-thEPJ Web Conf.(2022)·18 citations
24. 24*

    $\mathcal{N}=4$ supersymmetric Yang-Mills thermodynamics from effective field theory

    Jens O. Andersen🇳🇴 · Qianqian Du🇨🇳 · Michael Strickland🇺🇸 · Ubaid Tantary🇺🇸

    The free energy density of $\mathcal{N}=4$ supersymmetric Yang-Mills theory in four space-time dimensions is derived through second order in the 't Hooft coupling $\lambda$ at finite temperature using effective-field theory methods. The contributions to the free energy density at this order come from the hard scale $T$ and the soft scale $\sqrt{\lambda }T$. The effects of the scale $T$ are encoded in the coefficients of an effective three-dimensional field theory that is obtained by dimensional reduction at finite temperature. The effects of the electric scale $\sqrt{\lambda }T$ are taken into account by perturbative calculations in the effective theory.

    ↳ hep-thhep-phnucl-thPRD(2022)·13 citations
25. 25*

    General Analytical Conditions for Inflaton Fragmentation: Quick and Easy Tests for its Occurrence

    Jinsu Kim🇨🇭 · John McDonald🇬🇧

    Understanding the physics of inflaton condensate fragmentation in the early Universe is crucial as the existence of fragments in the form of non-topological solitons (oscillons or Q-balls) may potentially modify the evolution of the post-inflation Universe. Furthermore, such fragments may evolve into primordial black holes and form dark matter, or emit gravitational waves. Due to the non-perturbative and non-linear nature of the dynamics, most of the studies rely on numerical lattice simulations. Numerical simulations of condensate fragmentation are, however, challenging and, without knowing where to look in the parameter space, they are likely to be time-consuming as well. In this paper, we provide generic analytical conditions for the perturbations of an inflaton condensate to undergo growth to non-linearity in the cases of both symmetric and asymmetric inflaton potentials. We apply the conditions to various inflation models and demonstrate that our results are in good agreement with explicit numerical simulations. Our analytical conditions are easy to use and may be utilised in order to quickly identify models that may undergo fragmentation and determine the conditions under which they do so, which can guide subsequent in-depth numerical analyses.

    ↳ astro-ph.COhep-phPRD(2022)·13 citations
26. 26*

    Observational search for primordial chirality violations using galaxy angular momenta

    Pavel Motloch🇨🇦 · Ue-Li Pen🇨🇦 · Hao-Ran Yu🇨🇳

    We search for evidence of primordial chirality violation in the galaxy data from the Sloan Digital Sky Survey by comparing how strongly directions of galaxy angular momenta correlate with left and right helical components of a spin vector field constructed from the initial density perturbations. Within uncertainties, galaxy spins correlate with these two helical components identically, which is consistent with Universe without primordial chirality violation. Given current data, it is not yet possible to rule out maximal chiral violation, although the case of vanishing correlation with the right helical component is ruled out at about 3.8$\sigma$.

    ↳ astro-ph.COhep-phPRD(2022)·21 citations
27. 27*

    Double Copy of Form Factors and Higgs Amplitudes: A mechanism of turning spurious poles in Yang-Mills into physical poles in gravity

    Guanda Lin🇨🇳 · Gang Yang🇨🇳

    We extend the double copy picture of scattering amplitudes to a class of matrix elements (so-called form factors) that involve local gauge invariant operators. Both the Bern, Carrasco and Johansson (BCJ) and the Kawai, Lewellen and Tye (KLT) formalisms are considered and novel properties are observed. One remarkable feature is that through the double-copy construction, certain spurious poles hidden in the gauge form factors become physical propagators in gravity. This mechanism also reveals new hidden relations for form factors which can be understood as a generalization of the BCJ relations.

    ↳ hep-thhep-phPRL(2022)·20 citations
28. 28*

    What can CMB observations tell us about the neutrino distribution function?

    James Alvey🇳🇱 · Miguel Escudero🇩🇪 · Nashwan Sabti🇬🇧

    Cosmic Microwave Background (CMB) observations have been used extensively to constrain key properties of neutrinos, such as their mass. However, these inferences are typically dependent on assumptions about the cosmological model, and in particular upon the distribution function of neutrinos in the early Universe. In this paper, we aim to assess the full extent to which CMB experiments are sensitive to the shape of the neutrino distribution. We demonstrate that Planck and CMB-S4-like experiments have no prospects for detecting particular features in the distribution function. Consequently, we take a general approach and marginalise completely over the form of the neutrino distribution to derive constraints on the relativistic and non-relativistic neutrino energy densities, characterised by $N_{\mathrm{eff}}=3.0\pm 0.4$ and ${\rho }_{\nu ,0}^{\mathrm{NR}}<14\mathrm{eV}{\mathrm{cm}}^{-3}$ at 95% CL, respectively. The fact that these are the only neutrino properties that CMB data can constrain has important implications for neutrino mass limits from cosmology. Specifically, in contrast to the $\Lambda$CDM case where CMB and BAO data tightly constrain the sum of neutrinos masses to be $\sum m_{\nu }<0.12\mathrm{eV}$, we explicitly show that neutrino masses as large as $\sum m_{\nu }\sim 3\mathrm{eV}$ are perfectly consistent with this data. Importantly, for this to be the case, the neutrino number density should be suitably small such that the bound on ${\rho }_{\nu ,0}^{\mathrm{NR}}=\sum m_{\nu }{n}_{\nu ,0}$ is still satisfied. We conclude by giving an outlook on the opportunities that may arise from other complementary experimental probes, such as galaxy surveys, neutrino mass experiments and facilities designed to directly detect the cosmic neutrino background.

    ↳ astro-ph.COhep-phJCAP(2022)·49 citations
29. 29*

    Implementing the three-particle quantization condition for ${\pi }^{+}{\pi }^{+}{K}^{+}$ and related systems

    Tyler D. Blanton🇺🇸 · Fernando Romero-López🇺🇸 · Stephen R. Sharpe🇺🇸

    Recently, the formalism needed to relate the finite-volume spectrum of systems of nondegenerate spinless particles has been derived. In this work we discuss a range of issues that arise when implementing this formalism in practice, provide further theoretical results that can be used to check the implementation, and make available codes for implementing the three-particle quantization condition. Specifically, we discuss the need to modify the upper limit of the cutoff function due to the fact that the left-hand cut in the scattering amplitudes for two nondegenerate particles moves closer to threshold; we describe the decomposition of the three-particle amplitude ${\mathcal{K}}_{\text{df,3}}$ into the matrix basis used in the quantization condition, including both $s$ and $p$ waves, with the latter arising in the amplitude for two nondegenerate particles; we derive the threshold expansion for the lightest three-particle state in the rest frame up to $\mathcal{O}(1/L^5)$; and we calculate the leading-order predictions in chiral perturbation theory for ${\mathcal{K}}_{\text{df,3}}$ in the ${\pi }^{+}{\pi }^{+}{K}^{+}$ and ${\pi }^{+}{K}^{+}{K}^{+}$ systems. We focus mainly on systems with two identical particles plus a third that is different ("2+1" systems). We describe the formalism in full detail, and present numerical explorations in toy models, in particular checking that the results agree with the threshold expansion, and making a prediction for the spectrum of ${\pi }^{+}{\pi }^{+}{K}^{+}$ levels using the two- and three-particle interactions predicted by chiral perturbation theory.

    ↳ hep-lathep-phnucl-thJHEP(2022)·42 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.