Mon·Oct 2, 2023Monday·October 2, 2023

1. 01*

   Electroweak Precision Measurements of a Nearly-Degenerate $Z^{\prime }$-$Z$ System

   Dayun Qiu🇨🇳 · Yi-Lei Tang🇨🇳

   In this paper, we discuss the possibility to probe a nearly-degenerate $Z^{\prime }$-$Z$ system by analyzing the $Z$-lineshape at an electron-positron collider. Compared with the usual $Z^{\prime }$ in the literature well separated with the standard model (SM) $Z$ boson in mass, the nearly-degenerate $Z^{\prime }$-$Z$ mixing affects the observed effective ``oblique parameters'' $\tilde{S}$, $\tilde{T}$, $\tilde{U}$, and the effective deviation of ``number of neutrino species'' $\delta {\tilde{N}}_{\nu }$ in a more complicated way and cannot be simply computed perturbatively up to a particular order. Aiming at solving this problem, we write down a general simplified effective Lagrangian and enumerate some parameter spaces corresponding to some typical models, and suggest a method to extract the constraints by looking into the line-shape of the $Z$-like resonance at an electron-positron collider.

   hep-phJHEP(2024)·6 citations
2. 02*

   Diquarks and ${\Lambda }^0/{\pi }^{+}$, ${\Xi }^{-}/{\pi }^{+}$ ratios in the framework of the EPNJL model

   A. V. Friesen🇷🇺 · Yu. L. Kalinovsky🇷🇺

   The applicability of the effective models to the description of baryons and the behaviour of ratios of strange baryons to pions is discussed. In the framework of the EPNJL model, the Bethe - Salpeter equation is used to find masses of baryons, which are considered as diquark-quark state. Baryon melting is discussed at a finite chemical potential and a flavor dependence of the hadronic deconfinement temperature is pointed. It is shown that the description of the diquark-quark state at finite chemical potential is limited due to the occurrence of the Bose condensate. This effect is strongly manifested in the description of light diquarks and baryons. Both ${\Lambda }^0/{\pi }^{+}$ and ${\Xi }^{-}/{\pi }^{+}$ ratios show a sharp behaviour as functions of $T/{\mu }_B$ variable, where T and ${\mu }_B$ are calculated along the melting lines.

   hep-phnucl-thParticles(2023)·1 citation
3. 03*

   Measuring lepton number violation in heavy neutral lepton decays at the future muon collider

   Oleksii Mikulenko🇳🇱 · Mariia Marinichenko🇳🇱

   The future muon collider has the potential to discover feebly interacting particles in a wide range of masses above the electroweak scale. It is particularly suitable to search for heavy neutral leptons (HNLs), as their production cross section $\sigma \sim m_W^{-2}$ is not suppressed by the new physics scale. We demonstrate that the muon collider, with the capacity to observe up to $10^5$ events in the previously unexplored TeV mass range, provides the means to measure the fraction of lepton number violating (LNV) processes with precision at the level of a percent. This capability enables elucidating the nature of HNLs, allowing us to differentiate between Majorana, Dirac, and non-minimal scenarios featuring multiple degenerate HNLs. We link the observed fraction of LNV processes to the parameters of the model with three degenerate HNLs, which could be responsible for generating baryon asymmetry in the Universe. Additionally, we present a simple estimate for the number of signal events, as well as analyze the feasibility of vector boson fusion processes in searches for HNLs.

   hep-phJHEP(2024)·19 citations
4. 04*

   Extraction of the neutron F2 structure function from inclusive proton and deuteron deep-inelastic scattering data

   Shujie Li🇺🇸 · Alberto Accardi🇺🇸 · Matteo Cerutti🇺🇸 · Ishara. P. Fernando🇺🇸 · Cynthia E. Keppel🇺🇸 · Wally Melnitchouk🇺🇸 · Peter Monaghan🇺🇸 · Gabriel Niculescu🇺🇸 · Maria I. Niculescu🇺🇸 · Jeff. F. Owens🇺🇸

   The available world deep-inelastic scattering data on proton and deuteron structure functions F2p, F2d, and their ratios, are leveraged to extract the free neutron F2n structure function, the F2n/F2p ratio, and associated uncertainties using the latest nuclear effect calculations in the deuteron. Special attention is devoted to the normalization of the proton and deuteron experimental datasets and to the treatment of correlated systematic errors, as well as the quantification of procedural and theoretical uncertainties. The extracted F2n dataset is utilized to evaluate the Q2 dependence of the Gottfried sum rule and the nonsinglet F2p - F2n moments. To facilitate replication of our study, as well as for general applications, a comprehensive DIS database including all recent JLab 6 GeV measurements, the extracted F2n, a modified CTEQ-JLab global PDF fit named CJ15nlo_mod, and grids with calculated proton, neutron and deuteron DIS structure functions at next-to-leading order, are discussed and made publicly available.

   hep-phhep-exnucl-exnucl-thPRD(2024)·16 citations
5. 05*

   Study of two-body doubly charmful baryonic $B$ decays with $SU(3)$ flavor symmetry

   Yu-Kuo Hsiao🇨🇳

   Within the framework of $SU(3)$ flavor symmetry, we investigate two-body doubly charmful baryonic $B\to {\mathbf{B}}_c{\bar{\mathbf{B}}}_c^{\prime }$ decays, where ${\mathbf{B}}_c{\bar{\mathbf{B}}}_c^{\prime }$ represents the anti-triplet charmed dibaryon. We determine the $SU(3{)}_f$ amplitudes and calculate $\mathcal{B}(B^{-}\to {\Xi }_c^0{\bar{\Xi }}_c^{-})=(3.4_{-0.9}^{+1.0})\times 10^{-5}$ and $\mathcal{B}({\bar{B}}_s^0\to {\Lambda }_c^{+}{\bar{\Xi }}_c^{-})=(3.9_{-1.0}^{+1.2})\times 10^{-5}$ induced by the single $W$-emission configuration. We find that the $W$-exchange amplitude, previously neglected in studies, needs to be taken into account. It can cause a destructive interfering effect with the $W$-emission amplitude, alleviating the significant discrepancy between the theoretical estimation and experimental data for $\mathcal{B}({\bar{B}}^0\to {\Lambda }_c^{+}{\bar{\Lambda }}_c^{-})$. To test other interfering decay channels, we calculate $\mathcal{B}({\bar{B}}_s^0\to {\Xi }_c^{0(+)}{\bar{\Xi }}_c^{0(+)})=(3.0_{-1.1}^{+1.4})\times 10^{-4}$ and $\mathcal{B}({\bar{B}}^0\to {\Xi }_c^0{\bar{\Xi }}_c^0)=(1.5_{-0.6}^{+0.7})\times 10^{-5}$. We estimate non-zero branching fractions for the pure $W$-exchange decay channels, specifically $\mathcal{B}({\bar{B}}_s^0\to {\Lambda }_c^{+}{\bar{\Lambda }}_c^{-})=(8.1_{-1.5}^{+1.7})\times 10^{-5}$ and $\mathcal{B}({\bar{B}}^0\to {\Xi }_c^{+}{\bar{\Xi }}_c^{-})=(3.0\pm 0.6)\times 10^{-6}$. Additionally, we predict $\mathcal{B}(B_c^{+}\to {\Xi }_c^{+}{\bar{\Xi }}_c^0)=(2.8_{-0.7}^{+0.9})\times 10^{-4}$ and $\mathcal{B}(B_c^{+}\to {\Lambda }_c^{+}{\bar{\Xi }}_c^0)=(1.6_{-0.4}^{+0.5})\times 10^{-5}$, which are accessible to experimental facilities such as LHCb.

   hep-phhep-exJHEP(2023)·15 citations
6. 06*

   Constraining non-unitary neutrino mixing using matter effects in atmospheric neutrinos at INO-ICAL

   Sadashiv Sahoo🇮🇳 · Sudipta Das🇮🇳 · Anil Kumar🇮🇳 · Sanjib Kumar Agarwalla🇮🇳

   The mass-induced neutrino oscillation is a well established phenomenon that is based on the unitary mixing among three light active neutrinos. Remarkable precision on neutrino mixing parameters over the last decade or so has opened up the prospects for testing the possible non-unitarity of the standard 3$\nu$ mixing matrix, which may arise in the seesaw extensions of the Standard Model due to the admixture of three light active neutrinos with heavy isosinglet neutrinos. Because of this non-unitary neutrino mixing (NUNM), the oscillation probabilities among the three active neutrinos would be altered as compared to the probabilities obtained assuming a unitary 3$\nu$ mixing matrix. In such a NUNM scenario, neutrinos can experience an additional matter effect due to the neutral current interactions with the ambient neutrons. Atmospheric neutrinos having access to a wide range of energies and baselines can experience a significant modifications in Earth's matter effect due to NUNM. In this paper, we study in detail how the NUNM parameter ${\alpha }_{32}$ affects the muon neutrino and antineutrino survival probabilities in a different way. Then, we place a comparable and complementary constraint on ${\alpha }_{32}$ in a model independent fashion using the proposed 50 kt magnetized Iron Calorimeter (ICAL) detector under the India-based Neutrino Observatory (INO) project, which can efficiently detect the atmospheric ${\nu }_{\mu }$ and ${\bar{\nu }}_{\mu }$ separately in the multi-GeV energy range. Further, we discuss the advantage of charge identification capability of ICAL and the impact of uncertainties in oscillation parameters while constraining ${\alpha }_{32}$. We also compare the ${\alpha }_{32}$ sensitivity of ICAL with that of future long-baseline experiments DUNE and T2HK in isolation and combination.

   hep-phhep-exphysics.ins-detJHEP(2024)·10 citations
7. 07*

   Near-threshold resonance in $e^{+}{e}^{-}\to {\Lambda }_c{\bar{\Lambda }}_c$ process

   S.G. Salnikov🇷🇺 · A.I. Milstein🇷🇺

   We discuss the influence of various contributions of the ${\Lambda }_c{\bar{\Lambda }}_c$ potential on the energy dependence of the cross section $e^{+}{e}^{-}\to {\Lambda }_c{\bar{\Lambda }}_c$ near the threshold. New BESIII experimental data on the cross section and electromagnetic form factors $G_E$ and $G_M$ are taken into account. Our predictions are in good agreement with experimental data. We predict a bound state of ${\Lambda }_c{\bar{\Lambda }}_c$ at energy $\sim 38\text{MeV}$ below the threshold that may manifest itself in anomalous behavior of light meson production cross sections in a given energy region.

   hep-phhep-exnucl-thPRD(2023)·13 citations
8. 08*

   Doubly heavy tetraquark states in the constituent quark model using diffusion Monte Carlo method

   Yao Ma🇨🇳 · Lu Meng🇩🇪 · Yan-Ke Chen🇨🇳 · Shi-Lin Zhu🇨🇳

   We use the diffusion Monte Carlo method to calculate the doubly heavy tetraquark $T_{cc}$ system in two kinds of constituent quark models, the pure constituent quark model AL1/AP1 and the chiral constituent quark model. When the discrete configurations are complete and no spatial clustering is preseted, the AL1/AP1 model gives an energy of $T_{cc}$ close to the $D{D}^{\ast }$ threshold, and the chiral constituent quark model yields a deeply bound state. We further calculate all doubly heavy tetraquark systems with $J^P=0^{+},1^{+},2^{+}$, and provide the binding energies of systems with bound states. The $I(J^P)=0(0^{+})$ $bc\bar{n}\bar{n}$, $0(1^{+})$ $bb\bar{n}\bar{n}$, $0(1^{+})$ $bc\bar{n}\bar{n}$, $\frac{1}{2}(1^{+})$ $bb\bar{s}\bar{n}$ systems have bound states in all three models. Since the DMC method has almost no restriction on the spatial part, the resulting bound states have greater binding energies than those obtained in previous works.

   hep-phhep-exhep-latnucl-thPRD(2024)·30 citations
9. 09*

   Three-pion scattering: From the chiral Lagrangian to the lattice

   Jorge Baeza-Ballesteros🇪🇸 · Johan Bijnens🇸🇪 · Tomáš Husek🇸🇪 · Fernando Romero-López🇺🇸 · Stephen R. Sharpe🇺🇸 · Mattias Sjö🇸🇪

   In recent years, detailed studies of three-pion systems have become possible in lattice QCD. This has in turn led to interest in 3-to-3 scattering of pions in the chiral perturbation theory framework. In addition to being an interesting study of multi-meson dynamics in its own right, it provides a valuable handle on finite-volume effects and the pion mass dependence, thus complementing the lattice results. I present our derivation of the next-to-leading order amplitude for this process, as well as its conversion into the three-particle K-matrix, which enables direct comparison to the lattice. Our results significantly improve the agreement between theory and lattice, which was poor when only leading-order effects were taken into account.

   hep-phhep-latNucl.Part.Phys.Proc.(2024)·0 citations
10. 10*

    Kinematic scheme study of the $O(a^4)$ Bjorken sum rule and R ratio

    R.H. Mason🇬🇧 · J.A. Gracey🇬🇧

    The Bjorken sum rule and R ratio are constructed to $O(a^4)$ in the Landau gauge in the three momentum subtraction schemes of Celmaster and Gonsalves where $a$ $=$ $g^2/(16{\pi }^2)$. We aim to examine the issue of convergence for observables in the various schemes as well as to test ideas on whether using the discrepancy in different scheme values is a viable and more quantum field theoretic alternative to current ways of estimating the theory error on a measureable.

    hep-phPRD(2023)·5 citations
11. 11*

    Gravitational Waves and Gravitino Mass in No-Scale Supergravity Inflation with Polonyi Term

    Miguel Crispim Romão🇵🇹 · Stephen F. King🇬🇧

    We study a No-Scale supergravity inflation model which has a non-minimal deformation of the Kähler potential and a Wess-Zumino superpotential extended by the inclusion of a Polonyi mass term. The non-minimal structure of the Kähler potential is responsible for an inflexion point that can lead to the production of gravitational waves at late stages of inflation, while the Polonyi term breaks supersymmetry at the end of inflation, generating a non-vanishing gravitino mass. After a thorough parameter space scan, we identify promising points for gravitational wave production. We then study the resulting gravitational wave energy density for this set of points, and we observe that the gravitational waves should be observable in the next generation of both space-based and ground-based interferometers. Finally, we show how the presence of the Polonyi term can be used to further boost the gravitational wave energy density, which is correlated with the gravitino mass.

    hep-phastro-ph.COgr-qchep-thJCAP(2024)·3 citations
12. 12*

    $B\to K^{\ast }{M}_X$ vs $B\to K{M}_X$ as a probe of a scalar-mediator dark matter scenario

    Alexander Berezhnoy🇷🇺 · Dmitri Melikhov🇷🇺

    Recently, Belle II reported the observation of the decay $B\to K{M}_X$, $M_X$ the missing mass, with the branching ratio much exceeding $\mathcal{B}(B\to K\nu \bar{\nu })$ which is the only Standard Model (SM) process contributing to this reaction. If confirmed, this might be an indication of new nonSM particles produced in this decay. One of the possible explanations of the observed effect could be light dark-matter (DM) particles produced via a scalar mediator field. We give simple arguments, that a combined analysis of the $B\to K{M}_X$ and $B\to K^{\ast }{M}_X$ reactions would be a clean probe of the scalar mediator scenario: (i) making use of an observed value $\mathcal{B}(B\to K{M}_X)\simeq 5.4\mathcal{B}(B\to K\nu \bar{\nu }{)}_{\mathrm{SM}}$ and (ii) assuming that the effect is due to the light dark matter coupling to the top quark via a {\it scalar} mediator field, one finds an upper limit $\mathcal{B}(B\to K^{\ast }{M}_X)<2.8\mathcal{B}(B\to K^{\ast }\nu \bar{\nu }{)}_{\mathrm{SM}}$. Within the discussed scenario, this upper limit does not depend on the mass of the scalar mediator nor on the specific details of the unobserved dark-matter particles in the final state.

    hep-phEPL(2024)·41 citations
13. 13*

    An algebraic model to study the internal structure of pseudo-scalar mesons with heavy-light quark content

    B. Almeida-Zamora🇲🇽 · J.J. Cobos-Martínez🇲🇽 · A. Bashir🇲🇽 · K. Raya🇪🇸 · J. Rodríguez-Quintero🇪🇸 · J. Segovia🇪🇸

    The internal structure of all lowest-lying pseudo-scalar mesons with heavy-light quark content is studied in detail using an algebraic model that has been applied recently, and successfully, to the same physical observables of pseudo-scalar and vector mesons with hidden-flavor quark content, from light to heavy quark sectors. The algebraic model consists on constructing simple and evidence-based \emph{ansätze} of the meson's Bethe-Salpeter amplitude (BSA) and quark's propagator in such a way that the Bethe-Salpeter wave function (BSWF) can then be readily computed algebraically. Its subsequent projection onto the light front yields the light front wave function (LFWF) whose form allows us a simple access to the valence-quark Parton Distribution Amplitude (PDA) by integrating over the transverse momentum squared. We exploit our current knowledge of the PDAs of lowest-lying pseudo-scalar heavy-light mesons to compute their Generalized Parton Distributions (GPDs) through the overlap representation of LFWFs. From these three dimensional knowledge, different limits/projections lead us to deduce the related Parton Distribution functions (PDFs), Electromagnetic Form Factors (EFFs), and Impact parameter space GPDs (IPS-GPDs). When possible, we make explicit comparisons with available experimental results and earlier theoretical predictions.

    hep-phhep-exhep-latnucl-ex+1PRD(2024)·20 citations
14. 14*

    Hypergraphs in LHC Phenomenology -- The Next Frontier of IRC-Safe Feature Extraction

    Partha Konar🇮🇳 · Vishal S. Ngairangbam🇮🇳 · Michael Spannowsky🇬🇧

    In this study, we critically evaluate the approximation capabilities of existing infra-red and collinear (IRC) safe feature extraction algorithms, namely Energy Flow Networks (EFNs) and Energy-weighted Message Passing Networks (EMPNs). Our analysis reveals that these algorithms fall short in extracting features from any $N$-point correlation that isn't a power of two, based on the complete basis of IRC safe observables, specifically C-correlators. To address this limitation, we introduce the Hypergraph Energy-weighted Message Passing Networks (H-EMPNs), designed to capture any $N$-point correlation among particles efficiently. Using the case study of top vs. QCD jets, which holds significant information in its 3-point correlations, we demonstrate that H-EMPNs targeting up to N=3 correlations exhibit superior performance compared to EMPNs focusing on up to N=4 correlations within jet constituents.

    hep-phJHEP(2024)·9 citations
15. 15*

    Modelling uncertainties and prompt b-jet identification in $t\bar{t}b\bar{b}$ production with dilepton signatures at the LHC

    Giuseppe Bevilacqua🇬🇷

    As one of the primary backgrounds to $pp\to t\bar{t}H(H\to b\bar{b})$, the QCD process of $t\bar{t}b\bar{b}$ hadroproduction demands very accurate theoretical predictions and estimates of uncertainties. On top of that, the capacity of properly identifying prompt $b$-jets is beneficial for many analyses. In this contribution we discuss state-of-the-art predictions for $t\bar{t}b\bar{b}$ production with dilepton decays at the LHC, as obtained from full off-shell NLO QCD calculations. We evaluate the dominant uncertainties of the calculation and the impact of the off-shell effects on fiducial cross sections. Furthermore, we explore a kinematic prescription for the categorisation of prompt $b$-jets.

    hep-phPoS(2024)·0 citations
16. 16*

    Factorization and Resummation for Sequential Recombination Jet Cross Sections

    Thomas Becher🇨🇭 · Jürg Haag🇨🇭

    We extend the class of factorization theorems for non-global observables from fixed angular constraints to cross sections defined in terms of sequential jet clustering. The associated hard and soft functions depend not only on the directions of the hard partons, but also on their energy fractions. We derive the one-loop anomalous dimension of the hard functions that drives the leading-logarithmic resummation. The anomalous dimension imposes energy ordering, which simplifies the clustering sequence. We perform resummations for gap-between-jet observables defined with different jet algorithms and explain the effects of the clustering on the importance of secondary emissions and on the effective gap size.

    hep-phJHEP(2024)·19 citations
17. 17*

    Testing neutrino electromagnetic properties at current and future dark matter experiments

    Carlo Giunti🇮🇹 · Christoph A. Ternes🇮🇹

    We analyze data from the dark matter direct detection experiments PandaX-4T, LUX-ZEPLIN and XENONnT to place bounds on neutrino electromagnetic properties (magnetic moments, millicharges, and charge radii). We also show how these bounds will improve at the future facility DARWIN. In our analyses we implement a more conservative treatment of background uncertainties than usually done in the literature. From the combined analysis of all three experiments we can place very strong bounds on the neutrino magnetic moments and on the neutrino millicharges. We show that even though the bounds on the neutrino charge radii are not very strong from the analysis of current data, DARWIN could provide the first measurement of the electron neutrino charge radius, in agreement with the Standard Model prediction.

    hep-phhep-exPRD(2023)·42 citations
18. 18*

    First shot of the smoking gun: probing the electroweak phase transition in the 2HDM with novel searches for $A\to ZH$ in ${\ell }^{+}{\ell }^{-}t\bar{t}$ and $\nu \nu b\bar{b}$ final states

    Thomas Biekötter🇩🇪 · Sven Heinemeyer🇪🇸 · Jose Miguel No🇪🇸 · Kateryna Radchenko🇩🇪 · María Olalla Olea Romacho🇫🇷 · Georg Weiglein🇩🇪

    Recently the ATLAS collaboration has reported the first results of searches for heavy scalar resonances decaying into a $Z$ boson and a lighter new scalar resonance, where the $Z$ boson decays leptonically and the lighter scalar decays into a top-quark pair, giving rise to ${\ell }^{+}{\ell }^{-}t\bar{t}$ final states. This had previously been identified as a smoking-gun signature at the LHC for a first-order electroweak phase transition (FOEWPT) within the framework of two Higgs doublet models (2HDMs). In addition, ATLAS also presented new limits where the $Z$ boson decays into pairs of neutrinos and the lighter scalar resonance into bottom-quark pairs, giving rise to the $\nu \nu b\bar{b}$ final state. We analyze the impact of these new searches on the 2HDM parameter space, with emphasis on their capability to probe currently allowed 2HDM regions featuring a strong FOEWPT. We also study the complementarity of these new searches with other LHC probes that could target the FOEWPT region of the 2HDM. Remarkably, the ATLAS search in the ${\ell }^{+}{\ell }^{-}t\bar{t}$ final state shows a local $2.85\sigma$ excess (for masses of about 650 GeV and 450 GeV for the heavy and light resonance) in the 2HDM parameter region that would yield a FOEWPT in the early universe, which could constitute the first experimental hint of baryogenesis at the electroweak scale. We analyze the implications of this excess, and discuss the detectability prospects for the associated gravitational wave signal from the FOEWPT. Furthermore, we project the sensitivity reach of the ${\ell }^{+}{\ell }^{-}t\bar{t}$ signature for the upcoming runs of the LHC. Finally, we introduce the python package thdmTools, a state-of-art tool for the exploration of the 2HDM.

    hep-phJHEP(2024)·38 citations
19. 19*

    Searching for new physics at $\mu \to e$ facilities with ${\mu }^{+}$ and ${\pi }^{+}$ decays at rest

    Richard J. Hill🇺🇸 · Ryan Plestid🇺🇸 · Jure Zupan🇺🇸

    We investigate the ability of $\mu \to e$ facilities, Mu2e and COMET, to probe, or discover, new physics with their detector validation datasets. The validation of the detector response may be performed using a dedicated run with ${\mu }^{+}$, collecting data below the Michel edge, $E_e\lesssim 52$ MeV; an alternative strategy using ${\pi }^{+}\to e^{+}{\nu }_e$ may also be considered. We focus primarily on a search for a monoenergetic $e^{+}$ produced via two-body decays ${\mu }^{+}\to e^{+}X$ or ${\pi }^{+}\to e^{+}X$, with $X$ a light new physics particle. Mu2e can potentially explore new parameter space beyond present astrophysical and laboratory constraints for a set of well motivated models including: axion like particles with flavor violating couplings (${\mu }^{+}\to e^{+}a$), massive $Z^{\prime }$ bosons (${\mu }^{+}\to Z^{\prime }{e}^{+}$), and heavy neutral leptons (${\pi }^{+}\to e^{+}N$). The projected sensitivities presented herein can be achieved in a matter of days.

    hep-phhep-exPRD(2024)·35 citations
20. 20*

    Indirect constraints on top quark operators from a global SMEFT analysis

    Francesco Garosi🇮🇹 · David Marzocca🇮🇹 · Antonio Rodríguez Sánchez🇮🇹 · Alfredo Stanzione🇮🇹

    We perform a model-independent analysis of top-philic New Physics scenarios, under the assumption that only effective operators involving top quarks are generated at tree level. Within the SMEFT framework, we derive indirect constraints on Wilson Coefficients by combining a large set of low-energy observables: B-meson and kaon decays, meson mixing observables, precision electroweak and Higgs measurements, anomalous magnetic moments, lepton flavour violating processes, lepton flavour universality tests, and measurements of the Cabibbo angle. We consider the renormalization group evolution of the operators and use the one-loop matching of the SMEFT onto the LEFT. The global analysis is then used to perform one-parameter, two-parameter, and global fits, as well as applications to explicit ultraviolet models. We find that the inclusion of measurements from different physics sectors reveals a strong interplay and complementarity among the observables. The resulting constraints are also compared to direct bounds provided by top quark productions at the LHC.

    hep-phJHEP(2023)·57 citations
21. 21*

    EPiC-ly Fast Particle Cloud Generation with Flow-Matching and Diffusion

    Erik Buhmann🇩🇪 · Cedric Ewen🇩🇪 · Darius A. Faroughy🇺🇸 · Tobias Golling🇨🇭 · Gregor Kasieczka🇩🇪 · Matthew Leigh🇨🇭 · Guillaume Quétant🇨🇭 · John Andrew Raine🇨🇭 · Debajyoti Sengupta🇨🇭 · David Shih🇺🇸

    Jets at the LHC, typically consisting of a large number of highly correlated particles, are a fascinating laboratory for deep generative modeling. In this paper, we present two novel methods that generate LHC jets as point clouds efficiently and accurately. We introduce \epcjedi, which combines score-matching diffusion models with the Equivariant Point Cloud (EPiC) architecture based on the deep sets framework. This model offers a much faster alternative to previous transformer-based diffusion models without reducing the quality of the generated jets. In addition, we introduce \epcfm, the first permutation equivariant continuous normalizing flow (CNF) for particle cloud generation. This model is trained with {\it flow-matching}, a scalable and easy-to-train objective based on optimal transport that directly regresses the vector fields connecting the Gaussian noise prior to the data distribution. Our experiments demonstrate that \epcjedi and \epcfm both achieve state-of-the-art performance on the top-quark JetNet datasets whilst maintaining fast generation speed. Most notably, we find that the \epcfm model consistently outperforms all the other generative models considered here across every metric. Finally, we also introduce two new particle cloud performance metrics: the first based on the Kullback-Leibler divergence between feature distributions, the second is the negative log-posterior of a multi-model ParticleNet classifier.

    hep-phcs.LG49 citations
22. 22*

    Scalar boson emission from a magnetized relativistic plasma

    Jorge Jaber-Urquiza🇲🇽 · Igor A. Shovkovy🇺🇸

    We investigate the differential emission rate of neutral scalar bosons from a highly magnetized relativistic plasma. We show that three processes contribute at the leading order: particle splitting ($\psi \to \psi +\varphi$), antiparticle splitting ($\bar{\psi }\to \bar{\psi }+\varphi$), and particle-antiparticle annihilation ($\psi +\bar{\psi }\to \varphi$). This is in contrast to the scenario with zero magnetic field, where only the annihilation processes contribute to boson production. We examine the impact of Landau-level quantization on the energy dependence of the rate and investigate the angular distribution of emitted scalar bosons. The differential rate resulting from both (anti)particle splitting and annihilation processes are typically suppressed in the direction of the magnetic field and enhanced in perpendicular directions. Overall, the background magnetic field significantly amplifies the total emission rate. We speculate that our model calculations provide valuable theoretical insights with potentially important applications.

    hep-phhep-thnucl-thPRD(2023)·5 citations
23. 23*

    Data-driven reevaluation of $ft$-values in superallowed $\beta$ decays

    Chien-Yeah Seng🇺🇸 · Mikhail Gorchtein🇩🇪

    We present a comprehensive re-evaluation of the $ft$ values in superallowed nuclear $\beta$ decays crucial for the precise determination of $V_{ud}$ and low-energy tests of the electroweak Standard Model. It consists of the first, fully data-driven analysis of the nuclear $\beta$ decay form factor, that utilizes isospin relations to connect the nuclear charged weak distribution to the measurable charge distributions. This prescription supersedes previous shell-model estimations, and allows for a rigorous quantification of theory uncertainties in $f$ which is absent in the existing literature. Our new evaluation shows an overall downward shift of the central values of $f$ at the level of 0.01\%.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2024)·25 citations
24. 24*

    Power Spectrum in the Chaotic Regime of Axionic Blue Isocurvature Perturbations

    Daniel J. H. Chung🇺🇸 · Sai Chaitanya Tadepalli🇺🇸

    Large blue tilted spectral index axionic isocurvature perturbations can be produced when the axion sector is far out of equilibrium during inflation through an initial Peccei-Quinn (PQ) symmetry breaking field displacement along a nearly flat direction in the effective potential. As a companion to a previous work, we present analytic formulae for the blue isocurvature spectrum for the case of the kinetic energy density of the PQ symmetry breaking field being larger than the quartic power of the final spontaneous PQ symmetry breaking scale. It corresponds to a regime in which the nonlinearities of the classical potential become important many times during the formation of the axion isocurvature quantum perturbations leading to interesting resonant behavior. One consequence of this nonlinearity-driven resonance is the chaotic nature of the map that links the underlying Lagrangian parameters to the isocurvature amplitudes. We point out an accidental duality symmetry between the perturbation equations and the background field equations that can be used to understand this. Finally, we present two types of analytic results. The first relies on a computation utilizing an effective potential wherein fast time scale fluctuations have been integrated out. The second is grounded in a functional ansatz, requiring only a limited set of fitting parameters. Both analytic results should be useful for carrying out forecasts and fits to the data.

    ↳ astro-ph.COhep-phPRD(2024)·11 citations
25. 25*

    Nuclear Modification Factor in Pb-Pb and p-Pb collisions at $\sqrt{s_{NN}}$=5.02 TeV at LHC energies using Boltzmann Transport Equation with Tsallis Blast Wave Description

    Aditya Kumar Singh🇮🇳 · Aviral Akhil🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Pooja Pareek🇮🇳

    In this article, we have studied the nuclear modification factor measured in Pb-Pb collisions ($R_{PbPb}$) for ${\pi }^{\pm }$, $K^{\pm }$, $p+\bar{p}$, $K^{\ast 0}+\overline{K^{\ast 0}}$, $\varphi$ and in p-Pb collisions ($R_{pPb}$) for ${\pi }^{\pm }$, $K^{\pm }$, $p+\bar{p}$ at Large hadron collider (LHC) energy of $\sqrt{s_{NN}}$ = 5.02 TeV for the most central and peripheral collisions. We have also analysed the experimental data of transverse momentum ($p_T$) spectra for these identified hadrons at LHC for Pb-Pb as well as for p-Pb collisions. We have used Boltzmann transport equation (BTE) in relaxation time approximation (RTA) for this analysis. The Tsallis statistics is used as an initial distribution function and The Tsallis blast wave (TBW) model is employed as an equilibrium distribution in BTE. The present model fits the measured transverse momentum spectra, $R_{PbPb}$, and $R_{pPb}$ successfully upto $p_T$ = 8 GeV with a reasonable ${\chi }^2/ndf$ for all the considered hadrons at various centralities. The experimental data for $R_{pPb}$ are generated using the particle yields at pPb and pp collisions where number of binary collisions are taken from Glauber model calculations. We find that the average transverse flow velocity ($<{\beta }_r>$) follows the mass and centrality ordering and decreases with the mass as well as when one move from the central collisions to peripheral collisions. These findings are inline with the results of the hydrodynamical calculations.

    ↳ nucl-thhep-exhep-phnucl-exEur.Phys.J.Plus(2024)·5 citations
26. 26*

    $P_{tail}^{\alpha }$: a high resolution gamma/hadron and composition discriminant variable for Water-Cherenkov Detector cosmic-ray observatories

    Ruben Conceição🇵🇹 · Pedro J. Costa🇵🇹 · Lucio Gibilisco🇵🇹 · Mário Pimenta🇵🇹 · Bernardo Tomé🇵🇹

    The precise and efficient identification of the nature of the primary cosmic rays on an event-by-event basis stands as a fundamental aspiration for any cosmic ray observatory. In particular, the detection and characterization of gamma ray events are challenged by their occurrence within an overwhelmingly greater flux of charged cosmic rays spanning several orders of magnitude. The intricacies of distinguishing between cosmic ray compositions and the inherent uncertainties associated with hadronic interactions present formidable challenges, which, if not properly addressed, can introduce significant sources of systematic errors. This work introduces a novel composition discriminant variable, $P_{tail}^{\alpha }$, which quantifies the number of Water Cherenkov Detectors with a signal well above the mean signal observed in WCDs located at an equivalent distance from the shower core, in events with approximately the same energy at the ground. This new event variable is then shown to be, in the reconstructed energy range $10\mathrm{TeV}$ to $1.6\mathrm{PeV}$, well correlated with the total number of muons that hit, in the same event, all the observatory stations located at a distance greater than $200\mathrm{m}$ from the shower core. The two variables should thus have similar efficiencies in the selection of high-purity gamma event samples and in the determination of the nature of charged cosmic ray events.

    ↳ astro-ph.HEastro-ph.IMhep-exhep-ph+1PRD(2024)·6 citations
27. 27*

    Zemach and Friar radii of the proton and neutron from lattice QCD

    Dalibor Djukanovic🇩🇪 · Georg von Hippel🇩🇪 · Harvey B. Meyer🇩🇪 · Konstantin Ottnad🇩🇪 · Miguel Salg🇩🇪 · Hartmut Wittig🇩🇪

    We present the first lattice-QCD result for the Zemach and Friar radii of the proton and neutron. Our calculation includes both quark-connected and -disconnected diagrams and assesses all sources of systematic uncertainties arising from excited-state contributions, finite-volume effects and the continuum extrapolation. At the physical point, we obtain for the proton $r_Z^p=(1.013\pm 0.010(\mathrm{stat})\pm 0.012(\mathrm{syst}))\mathrm{fm}$ and $r_F^p=(1.301\pm 0.012(\mathrm{stat})\pm 0.014(\mathrm{syst}))\mathrm{fm}$. These numbers suggest small values of the Zemach and Friar radii of the proton, but are compatible with most of the experimental studies.

    ↳ hep-lathep-phnucl-thPRD(2024)·9 citations
28. 28*

    Contrasting Features of Parton Energy Loss in Heavy-ion Collisions at RHIC and the LHC

    Thomas Marshall🇺🇸 · Philip Suh🇺🇸 · Gang Wang🇺🇸 · Huan Zhong Huang🇺🇸

    Energetic quarks and gluons lose energy as they traverse the hot and dense medium created in high-energy heavy-ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC). The nuclear modification factor ($R_{AA}$) of leading particles quantifies parton energy loss in such collisions, with the particle spectrum in $p+p$ collisions as a reference. Previous $R_{AA}$ measurements at RHIC energies have revealed an approximately constant trend at high transverse momenta ($p_T$), implying a scenario where parton energy loss, $\Delta p_T$, scales proportionally with $p_T$, a feature naively expected from energy loss dynamics in elastic collisions. In this study, we investigate the LHC $R_{AA}$ measurements which exhibit a pronounced $p_T$ dependence of $R_{AA}$ for various particle species, and our analysis attributes this behavior to $\Delta p_T$ being approximately proportional to $\sqrt{p_T}$. These distinct features are consistent with model calculations of dominant radiative energy loss dynamics at the LHC, in contrast to the dominance of collisional energy loss at RHIC. Additionally, the linear increase of fractional energy loss with medium density at different $p_T$ magnitudes affirms the previous empirical observation that the magnitude of the energy loss depends mostly on the initial entropy density, with no significant path-length dependence. Implications on the dynamical scenarios of parton energy loss and future experimental investigations will also be discussed.

    ↳ nucl-thhep-exhep-phnucl-exCPC(2025)·2 citations
29. 29*

    Quantum Field Theory in Large N Wonderland: Three Lectures

    Paul Romatschke🇺🇸

    In these lecture notes, I review how to use large N techniques to solve quantum field theories in various dimensions. In particular, the case of N-dimensional quantum mechanics, non-relativistic cold and dense neutron matter, and scalar field theory in four dimensions are covered. A recurring theme is that large N solutions are fully non-perturbative, and can be used to reliably access quantum field theory for parameter regions where weak-coupling expansions simply fail.

    ↳ hep-thhep-phnucl-thActa Phys.Polon.B(2024)·18 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.