Fri·Dec 24, 2021Friday·December 24, 2021

1. 01*

   Two-body decays in deformed relativity

   Iarley P. Lobo🇧🇷 · Christian Pfeifer🇩🇪 · Pedro H. Morais🇧🇷 · Rafael Alves Batista🇪🇸 · Valdir B. Bezerra🇧🇷

   Deformed relativistic kinematics is a framework which captures effects, that are expected from particles and fields propagating on a quantum spacetime, effectively. They are formulated in terms of a modified dispersion relation and a modified momentum conservation equation. In this work we use Finsler geometry to formulate deformed relativistic kinematics in terms of particle velocities. The relation between the Finsler geometric velocity dependent formulation and the original momentum dependent formulation allows us to construct deformed Lorentz transformations between arbitrary frames. Moreover, we find the corresponding compatible momentum conservation equation to first order in the Planck scale deformation of special relativity based on the $\kappa$-Poincaré algebra in the bicrossproduct basis. We find that the deformed Lorentz transformations, as well as the deformed time dilation factor, contain terms that scale with the energy of the particle under consideration to the fourth power. We derive how the distributions of decay products are affected when the deformed relativity principle is satisfied and find, for the case of a pion decaying into a neutrino and a muon, that the ratio of expected neutrinos to muons with a certain energy is just slightly modified when compared to the predictions based on special relativity. We also discuss the phenomenological consequences of this framework for cosmic-ray showers in the atmosphere.

   hep-phgr-qchep-thJHEP(2022)·13 citations
2. 02*

   Co-interacting dark matter and conformally coupled light scalars

   Philippe Brax🇫🇷 · Carsten van de Bruck🇬🇧 · Sebastian Trojanowski🇵🇱

   The increasing observational pressure on the standard cosmological model motivates analyses going beyond the paradigm of the collision-less cold dark matter (DM). Since the only clear evidence for the existence of DM is based on gravitational interactions, it seems particularly fitting to study them in this sector where extensions to the standard model can be naturally introduced. A promising avenue can be obtained using modifications of the space-time metric coupled to DM and induced by the presence of a new ultra-light scalar field $\varphi$. The $\varphi$ field can contribute to the DM density and can couple all the matter species universally, including additional heavy DM particles. We present a simple two-component DM model employing derivative conformal interactions between the two DM species. This can simultaneously: 1) guarantee the necessary symmetries to stabilize the dark species, 2) predict a subdominant thermal relic density of the heavy DM component, and 3) alleviate small-scale structure tensions of the cold DM scenario due to the possible co-interactions in the dark sector. The scenario is highly predictive with future observational prospects ranging from the Large Hadron Collider (LHC) to gravitational-wave searches, and can be generalized to more rich and realistic dark sector models.

   hep-phastro-ph.COgr-qcPRD(2022)·3 citations
3. 03*

   Precision identified-hadron spectrum analysis for 5 TeV $\mathbf{p}$-$\mathbf{Pb}$ collisions -- Part II

   Thomas A. Trainor🇺🇸

   This is the second part of a two-part article on precision modeling of identified-hadron (PID) $p_t$ spectra from 5 TeV $p$-Pb collisions. In Part I a revised two-component (soft + hard) model (TCM) of PID spectra was introduced, an apparent detection inefficiency for protons was corrected and jet-related spectrum hard components isolated via an improved method were compared to a fixed TCM serving as reference. In the present article (Part II) the TCM is further elaborated to describe centrality variation of spectrum hard components (and therefore entire spectra) within data statistical uncertainties as determined by a standard statistical measure (Z-scores). The completed PID TCM is then used to investigate properties of spectrum and yield ratios (e.g. $p/\pi$ ratios) and ensemble-mean ${\bar{p}}_t$ data. Systematic differences are observed between meson and baryon hard components. With increasing $p$-Pb centrality meson hard components shift to lower $p_t$ while baryon hard components shift to higher $p_t$. Those trends explain quantitatively the main features and centrality variation of spectrum ratios. Ensemble-mean ${\bar{p}}_t$ trends are also predicted at the level of data statistical uncertainties, and details of the ${\bar{p}}_t$ centrality trends are explained quantitatively.

   hep-ph12 citations
4. 04*

   Radiative (anti)neutrino energy spectra from muon, pion, and kaon decays

   Oleksandr Tomalak🇺🇸

   To describe low-energy (anti)neutrino fluxes in modern coherent elastic neutrino-nucleus scattering experiments as well as high-energy fluxes in precision-frontier projects such as the Enhanced NeUtrino BEams from kaon Tagging (ENUBET) and the Neutrinos from STORed Muons (nuSTORM), we evaluate (anti)neutrino energy spectra from radiative muon (${\mu }^{-}\to e^{-}{\bar{\nu }}_e{\nu }_{\mu }(\gamma ),{\mu }^{+}\to e^{+}{\nu }_e{\bar{\nu }}_{\mu }(\gamma )$), pion ${\pi }_{\ell 2}$ (${\pi }^{-}\to {\mu }^{-}{\bar{\nu }}_{\mu }(\gamma ),{\pi }^{+}\to {\mu }^{+}{\nu }_{\mu }(\gamma )$), and kaon $K_{\ell 2}$ ($K^{-}\to {\mu }^{-}{\bar{\nu }}_{\mu }(\gamma ),K^{+}\to {\mu }^{+}{\nu }_{\mu }(\gamma )$) decays. We compare detailed $\mathrm{O}\left(\alpha \right)$ distributions to the well-known tree-level results, investigate electron-mass corrections and provide energy spectra in analytical form. Radiative corrections introduce continuous and divergent spectral components near the endpoint, on top of the monochromatic tree-level meson-decay spectra, which can change the flux-averaged cross section at $6\times 10^{-5}$ level for the scattering on ${}^{40}\mathrm{Ar}$ nucleus with (anti)neutrinos from the pion decay at rest. Radiative effects modify the expected (anti)neutrino fluxes from the muon decay around the peak region by $3-4$ permille, which is a precision goal for next-generation artificial neutrino sources.

   hep-phhep-exnucl-exnucl-thPLB(2022)·16 citations
5. 05*

   Production of twisted particles in heavy-ion collisions

   Liping Zou🇨🇳 · Pengming Zhang🇨🇳 · Alexander J. Silenko🇷🇺

   A prevalence of production of twisted (vortex) particles in noncentral heavy-ion collisions is shown. In such collisions, photons emitted due to the rotation of charges are highly twisted. Charged particles are produced in nonspreading multiwave states and have significant orbital angular momenta. It can be expected that an emission of any twisted particles manifesting themselves in specific effects is rather ubiquitous.

   hep-phquant-phJ.Phys.G(2023)·5 citations
6. 06*

   Inelastic Dark Matter from Dark Higgs Boson Decays at FASER

   Jinmian Li🇨🇳 · Takaaki Nomura🇨🇳 · Takashi Shimomura🇯🇵

   We consider inelastic dark matter scenarios with dark photon mediator and a dark Higgs boson. The dark Higgs boson spontaneously breaks the gauge symmetry associated with the dark photon, and gives the mass to the dark photon and the mass difference to dark particles. Such a dark Higgs boson can decay into the dark particles and hence can be another source of the dark particles at collider experiments. We analyze the sensitivity to decays of the excited state into the dark matter and charged particles at the FASER 2 experiment in fermion and scalar inelastic dark matter scenarios. We consider two mass spectra as illustrating examples in which the excited state can be produced only through the decay of dark Higgs boson. We show that unprobed parameter region can be explored in fermion dark matter scenario for the illustrating mass spectra.

   hep-phJHEP(2022)·16 citations
7. 07*

   EPPS21: A global QCD analysis of nuclear PDFs

   Kari J. Eskola🇫🇮 · Petja Paakkinen🇫🇮 · Hannu Paukkunen🇫🇮 · Carlos A. Salgado🇪🇸

   We present an updated global analysis of collinearly factorized nuclear parton distribution functions (PDFs) at next-to-leading order in perturbative QCD. In comparison to our previous fit, EPPS16, the present analysis includes more data from proton-lead collisions at the Large Hadron Collider: 5TeV double-differential CMS dijet and LHCb D-meson data, as well as 8TeV CMS W${}^{\pm }$ data. These new data lead to significantly better-constrained gluon distributions at small and intermediate values of the momentum fraction $x$, confirming the presence of shadowing and antishadowing for gluons in large nuclei. In addition, we include Jefferson Lab measurements of deeply inelastic scattering which probe nuclear PDFs at large $x$ and low virtualities. For the first time within the Hessian framework, we now also explore the uncertainties of nuclear PDFs due to the errors in the baseline proton PDFs. We release the results of our analysis as a new public parametrization of nuclear PDFs called EPPS21.

   hep-phEPJC(2022)·250 citations
8. 08*

   $T_{cc}^{+}$ and its partners

   Chengrong Deng🇨🇳 · Shi-Lin Zhu🇨🇳

   Inspired by the $T_{cc}^{+}$ signal discovered by the LHCb Collaboration, we systematically investigate the doubly heavy tetraquark states with the molecule configuration $[Q_1{\bar{q}}_2][Q_3{\bar{q}}_4]$ ($Q=c$ and $b$, $q=u$, $d$ and $s$) in a nonrelativistic quark model. The model involves a color screening confinement potential, meson-exchange interactions and one-gluon-exchange interactions. The $T_{cc}^{+}$ state with $I{J}^P=01^{+}$ is a very loosely bound deuteron-like state with a binding energy around 0.34 MeV and a huge size of 4.32 fm. Both the meson exchange force and the coupled channel effect play a pivotal role. Without the meson exchange force, there does not exist the $T_{cc}^{+}$ molecular state. In strong contrast, the QCD valence bond forms clearly in the $T_{bb}^{+}$ system when we turn off the meson-exchange force, which is very similar to the hydrogen molecule in QED. Moreover, the $T_{bb}^{+}$ becomes a helium-like QCD-atom if we increase the bottom quark mass by a factor of three. Especially, the $T_{bb}^{+}$ states with $01^{+}$, $T_{bc}^{+}$ with $00^{+}$ and $01^{+}$ and the $V$-spin antisymmetric states $T_{bbs}^{+}$ with $\frac{1}{2}{1}^{+}$, $T_{bcs}^{+}$ with $\frac{1}{2}{0}^{+}$ and $\frac{1}{2}{1}^{+}$ can form a compact, hydrogen molecule-like or deuteron-like bound state with different binding dynamics. The high-spin states $T_{bc}^{+}$ with $02^{+}$ and $T_{bcs}^{+}$ with $\frac{1}{2}{2}^{+}$ can decay into $D$-wave $\bar{B}D$ and ${\bar{B}}_{s}D$ although they are below the thresholds ${\bar{B}}^{\ast }{D}^{\ast }$ and ${\bar{B}}_s^{\ast }{D}^{\ast }$, respectively. The isospin and $V$-spin symmetric states are unbound. We also calculate their magnetic moments and axial charges.

   hep-phhep-exhep-latnucl-thPRD(2022)·99 citations
9. 09*

   Lepton Universality Violation by Kaluza-Klein Neutrinos in $b\to sll$ transition

   Janus Capellan Aban🇹🇼 · Chuan-Ren Chen🇹🇼 · Chrisna Setyo Nugroho🇹🇼

   Recent measure of $R_K$, involving the decays of $b\to s{l}^{+}{l}^{-}$, by the LHCb at CERN strengthened the deviation from the Standard Model prediction. The best fit in the updated global analysis suggests that the muon specific Wilson coefficients $C_9^{bs\mu \mu }=-C_{10}^{bs\mu \mu }$ should be about $-0.41$. In this paper, we show that the accumulate effects of KK modes of a singlet Dirac neutrino propagating in the large extra-dimensional space naturally provide $C_9^{bsll}=-C_{10}^{bsll}$ to explain the anomaly. By taking the muon Yukawa coupling to be of $\mathcal{O}(1)$, the fundamental scale in the extra-dimensional framework should be lowered down to about $2.9$ TeV if there are two additional spatial dimensions.

   hep-phPLB(2022)·2 citations
10. 10*

    New fermions in the light of the $(g-2{)}_{\mu }$

    J. C. Criado🇬🇧 · A. Djouadi🇪🇸 · N. Koivunen🇪🇪 · K. Müürsepp🇪🇪 · M. Raidal🇪🇪 · H.Veermäe

    The very precise measurement of the anomalous magnetic moment of the muon, recently released by the Muon g-2 experiment at Fermilab, can serve to set stringent constraints on new particles. If the observed 4$\sigma$ discrepancy from the Standard Model value is indeed real, it will set a tight margin on the scale of the masses and couplings of these particles. Instead, if the discrepancy is simply a result of additional theoretical and experimental uncertainties to be included, strong constraints can be put on their parameters. In this mini-review, we summarize the impact of the latest muon g-2 measurement on new fermions that are predicted by a wide range of new physics models and with exotic quantum numbers and interactions. We will particularly discuss the case of vector-like leptons, excited leptons, and supersymmetric fermions, as well as spin-3/2 isosinglet fermions, which have been advocated recently.

    hep-phFront.in Phys.(2022)·4 citations
11. 11*

    Measurement of Higgs boson self-couplings through $2\to 3$ vector bosons scattering in future muon colliders

    Junmou Chen🇨🇳 · Tong Li🇨🇳 · Chih-Ting Lu🇰🇷 · Yongcheng Wu🇺🇸 · Chang-Yuan Yao🇨🇳

    The $2\to 3$ scattering of longitudinal vector bosons (VBS) has been proven to be a complementary channel to measure the Higgs self-couplings in the Standard Model (SM) and the SM effective field theory (SMEFT) at colliders. We perform the first comprehensive study of all main $2\to 3$ VBS processes at high-energy muon colliders, especially including background analysis. The main contributing channels turn out to be the scattering of $W^{+}{W}^{-}\to W^{+}{W}^{-}h$, $ZZh$ and $hhh$. We obtain the constraints on $c_6$ and $c_{{\Phi }_1}$ which are the Wilson coefficients of the dimension-6 operators relevant for Higgs self-couplings in the SMEFT. With the center-of-mass energies of 10 TeV and 30 TeV, we find the expected sensitivity to the coefficients $c_6/{\Lambda }^2$ and $c_{{\Phi }_1}/{\Lambda }^2$ can reach the level of 0.01 TeV${}^{-2}$. The tightest constraints come from the $hhh$ channel, while the constraints from $WWh$ are also comparable. Our results crucially depend on selecting the longitudinal polarizations for the final $W$ and $Z$ bosons. We then study how the sensitivities change by varying the efficiency of tagging longitudinal polarizations, and find that the significance remains consistently high.

    hep-phPRD(2022)·24 citations
12. 12*

    Benchmarking Di-Higgs Production in Various Extended Higgs Sector Models

    Hamza Abouabid🇲🇦 · Abdesslam Arhrib🇲🇦 · Duarte Azevedo🇩🇪 · Jaouad El Falaki🇲🇦 · Pedro. M. Ferreira🇵🇹 · Margarete Muhlleitner🇩🇪 · Rui Santos🇵🇹

    We present a comprehensive study on Higgs pair production in various archetypical extended Higgs sectors such as the real and the complex 2-Higgs-Doublet Model, the 2-Higgs-Doublet Model augmented by a real singlet field and the Next-to-Minimal Supersymmetric extension of the Standard Model. We take into account all relevant theoretical and experimental constraints, in particular the experimental limits on non-resonant and resonant Higgs pair production. We present the allowed cross sections for Standard Model (SM)-like Higgs pair production and the ranges of the SM-like Yukawa and trilinear Higgs self-coupling that are still compatible with the applied constraints. Furthermore, we give results for the pair production of a SM-like with a non-SM-like Higgs boson and for the production of a pair of non-SM-like Higgs bosons. We find that di-Higgs production in the models under investigation can exceed the SM rate substantially, not only in the non-resonance region but also due to resonant enhancement. We give several benchmarks with interesting features such as large cross sections, the possibility to test CP violation, Higgs-to-Higgs cascade decays or di-Higgs production beating single Higgs production. In all of our benchmark points, the next-to-leading order QCD corrections are included in the large top-mass limit. For these points, we found that, depending on the model and the Higgs pair final state, the corrections increase the leading order cross section by a factor of 1.79 to 2.24. We also discuss the relation between the description of Higgs pair production in an effective field theory approach and in the specific models investigated here.

    hep-phhep-exJHEP(2022)·86 citations
13. 13*

    Real-time methods for spectral functions

    Johannes V. Roth🇩🇪 · Dominik Schweitzer🇩🇪 · Leon J. Sieke🇩🇪 · Lorenz von Smekal🇩🇪

    In this paper we develop and compare different real-time methods to calculate spectral functions. These are classical-statistical simulations, the Gaussian state approximation (GSA), and the functional renormalization group (FRG) formulated on the Keldysh closed-time path. Our test-bed system is the quartic anharmonic oscillator, a single self-interacting bosonic degree of freedom, coupled to an external heat bath providing dissipation analogous to the Caldeira-Leggett model. As our benchmark we use the spectral function from exact diagonalization with constant Ohmic damping. To extend the GSA for the open system, we solve the corresponding Heisenberg-Langevin equations in the Gaussian approximation. For the real-time FRG, we introduce a novel general prescription to construct causal regulators based on introducing scale-dependent fictitious heat baths. Our results explicitly demonstrate how the discrete transition lines of the quantum system gradually build up the broad continuous structures in the classical spectral function as temperature increases. At sufficiently high temperatures, classical, GSA and exact-diagonalization results all coincide. The real-time FRG is able to reproduce the effective thermal mass, but overestimates broadening and only qualitatively describes higher excitations, at the present order of our combined vertex and loop expansion. As temperature is lowered, the GSA follows the ensemble average of the exact solution better than the classical spectral function. In the low-temperature strong-coupling regime, the qualitative features of the exact result are best captured by our real-time FRG calculation, with quantitative improvements to be expected at higher truncation orders.

    hep-phPRD(2022)·27 citations
14. 14*

    Scalar Dark Matter and Radiative Dirac neutrino mass in an extended $U(1{)}_{B-L}$ model

    Subhasmita Mishra🇹🇷 · Nimmala Narendra🇮🇳 · Prafulla Kumar Panda🇮🇳 · Nirakar Sahoo🇮🇳

    We explore a gauged $U(1{)}_{B-L}$ extension of standard model with inclusion of three right-handed neutrinos of exotic $B-L$ charges to cancel the gauge anomaly. Non-trivial transformation of new particles under $B-L$ symmetry forbids the neutrino mass at tree level and hence a small Dirac mass can be generated radiatively at one loop with a doublet fermion and singlet scalar. We also discuss the phenomenology of a scalar dark matter, which can be obtained from the mixing of neutral CP even component of a doublet and real singlet scalar. An adhoc $Z_2$ symmetry is required in the current framework to stabilize the dark matter candidate. Presence of new particles with $Z_2$ odd charges and small mass splitting, makes the phenomenology more interesting by governing the relic density with co-annihilation processes. We explore the spin-independent direct detection constraints on dark matter via the scalar mediation. The new particle spectrum not only opens up new window for dark matter study but also satisfy the constraints from lepton flavor violating decay of $\mu \to e\gamma$.

    hep-phNPB(2022)·12 citations
15. 15*

    Gravitational shine of dark domain walls

    E. Babichev🇫🇷 · D. Gorbunov🇷🇺 · S. Ramazanov🇨🇿 · A. Vikman🇨🇿

    Cosmic domain walls are harmless, provided that their tension decreases with expansion of the Universe. This setup can be realized, if the scale of spontaneous symmetry breaking is induced dynamically through the interaction with hot primordial plasma. In that case, the domain wall tension can attain large values in the early Universe without any conflict with observations. Owing to the large initial tension, these topological defects may serve as a powerful source of gravitational waves. We make a preliminary estimate of the gravitational wave spectrum and argue that it is distinct from the spectrum produced by other sources, in particular by domain walls of a constant tension. The resulting gravitational wave signal is in the range accessible by Einstein Telescope, DECIGO, TianQin, LISA, IPTA, or SKA, if the field constituting the domain walls is very feebly coupled with hot primordial plasma and has tiny self-interactions. In particular, one can consider this field for the role of Dark Matter. We discuss various Dark Matter production mechanisms and properties of the emitted gravitational waves associated with them. We find that the conventional freeze-out and freeze-in mechanisms lead to large and perhaps unobservable frequency of gravitational waves. However, the Dark Matter production is also possible at the second order phase transition leading to the domain wall formation or at the inverse phase transition, when the domain walls get dissolved eventually. In both cases, there is essentially no lower bound on the frequency of emitted gravitational waves.

    hep-phastro-ph.COgr-qcJCAP(2022)·58 citations
16. 16*

    Investigation of the possible $D{\bar{D}}^{\ast }$/$B{\bar{B}}^{\ast }$ and $D{D}^{\ast }$/$\bar{B}{\bar{B}}^{\ast }$ molecule states

    Meng-Jie Zhao🇨🇳 · Zhen-Yang Wang🇨🇳 · Chao Wang🇨🇳 · Xin-Heng Guo🇨🇳

    In this work, we systematically study the $D{\bar{D}}^{\ast }$/$B{\bar{B}}^{\ast }$ and $D{D}^{\ast }$/$\bar{B}{\bar{B}}^{\ast }$ systems with the Bethe-Salpeter equation in the ladder and instantaneous approximations for the kernel. By solving the Bethe-Salpeter equation numerically with the kernel containing the direct and crossed one particle-exchange diagrams and introducing three different form factors (monopole, dipole, and exponential form factors) at the vertices, we find only the isoscalar $D{\bar{D}}^{\ast }$/$B{\bar{B}}^{\ast }$ and $D{D}^{\ast }$/$\bar{B}{\bar{B}}^{\ast }$ systems can exist as bound states. This indicate that the $X(3872)$ and $T_{cc}^{+}$ could be accommodated as $I^G(J^{PC})=0^{+}(1^{++})$ $D{\bar{D}}^{\ast }$ and $(I)J^P=(0)1^{+}$ $D{D}^{\ast }$ molecular states while the molecular state explanations for $Z_b(10610)$ and $Z_c(3900)$ are excluded.

    hep-phPRD(2022)·35 citations
17. 17*

    Top-pair events with B-hadrons at the LHC

    Terry Generet🇩🇪

    In these proceedings, we summarise the results of the recent calculation of the NNLO QCD corrections for the production of a top-quark pair in association with a bottom-flavoured hadron. The results consist of differential distributions of observables involving the identified hadron.

    hep-ph0 citations
18. 18*

    Simplified models for resonant neutral scalar production with missing transverse energy final states

    Henning Bahl🇺🇸 · Victor Martin Lozano🇩🇪 · Georg Weiglein🇩🇪

    Additional Higgs bosons appear in many extensions of the Standard Model (SM). While most existing searches for additional Higgs bosons concentrate on final states consisting of SM particles, final states containing beyond the SM (BSM) particles play an important role in many BSM models. In order to facilitate future searches for such final states, we develop a simplified model framework for heavy Higgs boson decays to a massive SM boson as well as one or more invisible particles. Allowing one kind of BSM mediator in each decay chain, we classify the possible decay topologies for each final state, taking into account all different possibilities for the spin of the mediator and the invisible particles. Our comparison of the kinematic distributions for each possible model realization reveals that the distributions corresponding to the different simplified model topologies are only mildly affected by the different spin hypotheses, while there is significant sensitivity for distinguishing between the different decay topologies. As a consequence, we point out that expressing the results of experimental searches in terms of the proposed simplified model topologies will allow one to constrain wide classes of different BSM models. The application of the proposed simplified model framework is explicitly demonstrated for the example of a mono-Higgs search. For each of the simplified models that are proposed in this paper we provide all necessary ingredients for performing Monte-Carlo simulations such that they can readily be applied in experimental analyses.

    hep-phhep-exJHEP(2022)·7 citations
19. 19*

    Neutrinoless Double Beta Decay via Light Neutralinos in R-Parity Violating Supersymmetry

    Patrick D. Bolton🇬🇧 · Frank F. Deppisch🇬🇧 · P. S. Bhupal Dev🇺🇸

    We perform a study of neutrinoless double beta ($0\nu \beta \beta$) decay mediated by the lightest neutralino of arbitrary mass in the Minimal Supersymmetric Standard Model (MSSM) under the presence of R-parity violating trilinear interactions. In this scenario, the exchange of the lightest neutralino can result in $0\nu \beta \beta$ decay of either long-range or short-range behaviour, depending on the neutralino mass. Using nuclear matrix elements calculated in the Interacting Boson Model, we use an interpolation between the long- and short-range behaviours with an approximate formula. The non-observation of $0\nu \beta \beta$ decay is then used to place constraints on the supersymmetry parameter space, compatible with constraints from collider experiments. We compare these constraints to bounds from pion decays, CKM unitarity and Big Bang Nucleosynthesis.

    hep-phJHEP(2022)·21 citations
20. 20*

    $B\to D\ell {\nu }_{\ell }$ form factors beyond leading power and extraction of $|V_{cb}|$ and $R(D)$

    Jing Gao🇨🇳 · Tobias Huber🇩🇪 · Yao Ji🇩🇪 · Chao Wang🇨🇳 · Yu-Ming Wang🇨🇳 · Yan-Bing Wei🇨🇳

    We investigate the subleading-power corrections to the exclusive $B\to D\ell {\nu }_{\ell }$ form factors at $\mathcal{O}({\alpha }_s^0)$ in the light-cone sum rules (LCSR) framework by including the two- and three-particle higher-twist contributions from the $B$-meson light-cone distribution amplitudes up to the twist-six accuracy, by taking into account the subleading terms in expanding the hard-collinear charm-quark propagator, and by evaluating the hadronic matrix element of the subleading effective current $\bar{q}{\gamma }_{\mu }i/D_{\perp }/(2m_b)h_v$. Employing further the available leading-power results for the semileptonic $B\to D$ form factors at the next-to-leading-logarithmic level and combining our improved LCSR predictions with the recent lattice determinations, we then carry out a comprehensive phenomenological analysis on the semi-leptonic $B\to D\ell {\nu }_{\ell }$ decay. We extract $|V_{cb}|=\left(40.2_{-0.5}^{+0.6}{|}_{\mathrm{th}}{}_{-1.4}^{+1.4}{|}_{\exp }\right)\times 10^{-3}$ ($|V_{cb}|=\left(40.9_{-0.5}^{+0.6}{|}_{\mathrm{th}}{}_{-1.0}^{+1.0}{|}_{\exp }\right)\times 10^{-3}$) using the BaBar (Belle) experimental data, and particularly obtain for the gold-plated ratio $R(D)=0.302\pm 0.003$.

    hep-phJHEP(2022)·48 citations
21. 21*

    Classical and Quantum Evolution in a Simple Coherent Neutrino Problem

    Joshua D. Martin🇺🇸 · A. Roggero🇺🇸 · Huaiyu Duan🇺🇸 · J. Carlson🇺🇸 · V. Cirigliano🇺🇸

    The extraordinary neutrino flux produced in extreme astrophysical environments like the early universe, core-collapse supernovae and neutron star mergers may produce coherent quantum neutrino oscillations on macroscopic length scales. The Hamiltonian describing this evolution can be mapped into quantum spin models with all-to-all couplings arising from neutrino-neutrino forward scattering. To date many studies of these oscillations have been performed in a mean-field limit where the neutrinos time evolve in a product state. In this paper we examine a simple two-beam model evolving from an initial product state and compare the mean-field and many-body evolution. The symmetries in this model allow us to solve the real-time evolution for the quantum many-body system for hundreds or thousands of spins, far beyond what would be possible in a more general case with an exponential number ($2^N$) of quantum states. We compare mean-field and many-body solutions for different initial product states and ratios of one- and two-body couplings, and find that in all cases in the limit of infinite spins the mean-field (product state) and many-body solutions coincide for simple observables. This agreement can be understood as a consequence of the fact that the typical initial condition represents a very local but dense distribution about a mean energy in the spectrum of the Hamiltonian. We explore quantum information measures like entanglement entropy and purity of the many-body solutions, finding intriguing relationships between the quantum information measures and the dynamical behavior of simple physical observables.

    hep-phastro-ph.HEnucl-thPRD(2022)·47 citations
22. 22*

    3HDM with $\Delta (27)$ symmetry and its phenomenological consequences

    J. Kalinowski🇵🇱 · W. Kotlarski🇩🇪 · M. N. Rebelo🇵🇹 · I. de Medeiros Varzielas🇵🇹

    We perform a comprehensive analysis of a version of the 3-Higgs doublet model whose scalar potential is invariant under a global $\Delta (27)$ discrete symmetry and where the three scalar doublets are chosen to transform as a triplet under this discrete group. For each of the known tree-level minima we study the mass spectra and use the oblique parameters $STU$ as well as perturbative unitarity to constrain the parameter space of the model. We then discuss phenomenological consequences of some leading order flavour mixing quark Yukawa couplings by considering the flavour violation process $b\to s\gamma$. We show that perturbative unitarity significantly constrains parameters of the model while, conversely, the beyond the Standard Model contributions to the $b\to s\gamma$ decay are automatically tamed by the symmetry.

    hep-phJHEP(2023)·14 citations
23. 23*

    Status of NNLO QCD corrections for process with one or more jets in the final state at the LHC

    João Pires🇵🇹

    The abundant amount of data to be collected by the ATLAS and CMS collaborations in future runs of the Large Hadron Collider at CERN opens up a new era of precision physics. Some of the most prominent precision observables are related to processes with one or more jets in the final state. In order to fully exploit the potential of the LHC and the HL-LHC, it is imperative to make theoretical predictions at the level of accuracy that matches or even exceeds that of the upcoming measurements. In this talk we present a review of the status of theoretical predictions including NNLO QCD corrections for process with one or more jets in the final state at the LHC.

    hep-phPoS(2022)·0 citations
24. 24*

    A Green's basis for the bosonic SMEFT to dimension 8

    Mikael Chala🇪🇸 · Álvaro Díaz-Carmona🇪🇸 · Guilherme Guedes🇪🇸

    We present a basis of dimension-eight Green's functions involving Standard Model (SM) bosonic fields, consisting of 86 new operators. Rather than using algebraic identities and integration by parts, we prove the independence of these interactions in momentum space, including a discussion on evanescent bosonic operators. Our results pave the way for renormalising the SM effective field theory (SMEFT), as well as for performing matching of ultraviolet models onto the SMEFT, to higher order. To demonstrate the potential of our construction, we have implemented our basis in matchmakereft and used it to integrate out a heavy singlet scalar and a heavy quadruplet scalar up to one loop. We provide the corresponding dimension-eight Wilson coefficients. Likewise, we show how our results can be easily used to simplify cumbersome redundant Lagrangians arising, for example, from integrating out heavy fields using the path-integral approach to matching.

    hep-phJHEP(2022)·53 citations
25. 25*

    Investigating Leggett-Garg inequality in neutrino oscillations -- role of decoherence and decay

    Sheeba Shafaq🇮🇳 · Tanmay Kushwaha🇮🇳 · Poonam Mehta🇮🇳

    Neutrinos, due to their weakly interacting nature, provide us with a unique opportunity to test foundations of quantum mechanics over macroscopic distances. There has been considerable theoretical and experimental interest in examining the extent of violation of Leggett-Garg inequalities (LGI) in the context of neutrino flavour oscillations. While it is established that neutrino oscillations occur due to mass and mixing among the three generations of neutrinos, sub-dominant effects due to physics beyond the Standard Model (SM) are not yet ruled out. As we are entering the precision era in neutrino physics, it is possible that some of these effects may leave an imprint on data. Thus, it is worthwhile to investigate different physics scenarios beyond the SM and study their impact on oscillation probabilities. In the present work, we invoke damping effects (including decoherence and decay) on oscillation probabilities and study their implications on the LGI.

    hep-phhep-exquant-ph9 citations
26. 26*

    Lepton PDFs and Multipurpose Single Lepton Searches at the LHC

    Herbi K. Dreiner🇩🇪 · Victor Martin Lozano🇩🇪 · Saurabh Nangia🇩🇪 · Toby Opferkuch🇨🇭

    A final state consisting of one charged lepton, at least one jet, and little missing transverse energy can be a very promising signature of new physics at the LHC across a wide range of models. However, it has received only limited attention so far. In this work we discuss the potential sensitivity of this channel to various new physics scenarios. To demonstrate our point, we consider its application to lepton parton density functions (PDFs) at the LHC in the context of supersymmetry. These lepton PDFs can lead to resonant squark production (similar to leptoquarks) via lepton number violating couplings present in R-parity Violating Supersymmetry (RPV-SUSY). Unlike leptoquarks, in RPV-SUSY there are many possible decay modes leading to a wide range of signatures. We propose two generic search regions: (a) A single first or second generation charged lepton, exactly 1 jet and low missing transverse energy, and (b) A single first or second generation charged lepton, at least 3 jets, and low missing transverse energy. We demonstrate that together these cover a large range of RPV-SUSY signatures, and have the potential to perform better than existing low-energy bounds, while being general enough to extend to a wide range of possible models hitherto not explored at the LHC.

    hep-phhep-exPRD(2023)·6 citations
27. 27*

    Vector Boson Dark Matter From Trinification

    K.S. Babu🇺🇸 · Sudip Jana🇩🇪 · Anil Thapa🇺🇸

    We show how trinification models based on the gauge group $SU(3{)}_C\times SU(3{)}_L\times SU(3{)}_R$ realized near the TeV scale can provide naturally a variety of dark matter (DM) candidates. These models contain a discrete $T$ parity which may remain unbroken even after spontaneous symmetry breaking. The lightest $T$-odd particle, which could be a fermion, a scalar, or a gauge boson, can constitute the dark matter of the universe. This framework naturally admits a doublet-singlet fermionic DM, a singlet scalar DM, or a vector boson DM. Here we develop the vector boson DM scenario wherein the DM couples off-diagonally with the usual fermions and vector-like fermions present in the theory. We show consistency of this framework with dark matter relic abundance and direct detection limits as well as LHC constraints. We derive upper limits of 900 GeV on the vector gauge boson DM mass and 4.5 TeV on the vector-like quarks and lepton masses. We also show the consistency of spontaneous gauge symmetry breaking down to Standard Model times an extra $U(1)$ while preserving the $T$-parity.

    hep-phJHEP(2022)·14 citations
28. 28*

    Scalar field couplings to quadratic curvature and decay into gravitons

    Yohei Ema🇺🇸 · Kyohei Mukaida🇯🇵 · Kazunori Nakayama🇯🇵

    Any field, even if it lives in a completely hidden sector, interacts with the visible sector at least via the gravitational interaction. In this paper, we show that a scalar field in such a hidden sector generically couples to the quadratic curvature via dimension five operators, i.e., $\varphi R^2$, $\varphi R^{\mu \nu }{R}_{\mu \nu }$, $\varphi R_{\mu \nu \rho \sigma }{R}^{\mu \nu \rho \sigma }$, $\varphi R_{\mu \nu \rho \sigma }{\tilde{R}}^{\mu \nu \rho \sigma }$, because they can emerge if there exist particles heavier than it. We derive these scalar couplings to the quadratic curvature by integrating out heavy particles in a systematic manner. Such couplings are of phenomenological interest since some of them induce the scalar decay into the graviton pair. We point out that the decay of a scalar field can produce a substantial amount of the stochastic cosmic graviton background at high frequency since the suppression scale of these operators is given by the mass of heavy particles not by the Planck scale. The resultant graviton spectrum is computed in some concrete models.

    hep-phhep-thJHEP(2022)·36 citations
29. 29*

    Neutrinoless double beta decay in the minimal type-I seesaw model: How the enhancement or cancellation happens?

    Dong-Liang Fang🇨🇳 · Yu-Feng Li🇨🇳 · Yi-Yu Zhang🇨🇳

    We discuss the contribution of right-handed neutrinos (RHNs) to the effective neutrino mass of the neutrinoless double beta decay within the minimal type-I seesaw model using the intrinsic seesaw relation of neutrino mass and mixing parameters and the relative mass dependence of the nuclear matrix elements. In the viable parameter space, we find the possibilities of both the enhancement and cancellation to the effective neutrino mass from RHNs. The bounds on the parameter space of the RHNs can be determined with the effective neutrino mass extracted from neutrinoless double beta decay experiments.

    hep-phhep-exPLB(2022)·16 citations
30. 30*

    Spacelike zero crossings and timelike phases in the electromagnetic form factors of vector mesons

    Stefan Leupold (Uppsala U.)🇸🇪

    Some form factors of ground-state hadrons with spin might show a zero crossing at spacelike momenta of electron-hadron scattering. In the timelike region of hadron-antihadron production by electron-positron collisions the form factors become complex. When the hadrons decay, the relative phases between form factors can be measured by the angular distributions of their decay products. Using analyticity and the QCD high-energy limits for constraint-free form factors and for helicity amplitudes, we show how a single zero crossing in the spacelike region is related to the high-energy limit of the phase in the timelike region. Theoretical predictions for such zero crossings can therefore be tested by experimental measurements, e.g. by Belle II, in the high-energy timelike region. In the present work, this line of reasoning is applied to vector mesons.

    hep-ph1 citation
31. 31*

    The Quantum Trellis: A classical algorithm for sampling the parton shower with interference effects

    Sebastian Macaluso🇺🇸 · Kyle Cranmer🇺🇸

    Simulations of high-energy particle collisions, such as those used at the Large Hadron Collider, are based on quantum field theory; however, many approximations are made in practice. For example, the simulation of the parton shower, which gives rise to objects called `jets', is based on a semi-classical approximation that neglects various interference effects. While there is a desire to incorporate interference effects, new computational techniques are needed to cope with the exponential growth in complexity associated to quantum processes. We present a classical algorithm called the quantum trellis to efficiently compute the un-normalized probability density over N-body phase space including all interference effects, and we pair this with an MCMC-based sampling strategy. This provides a potential path forward for classical computers and a strong baseline for approaches based on quantum computing.

    hep-phcs.DSquant-ph3 citations
32. 32*

    Shedding Flavor on Dark via Freeze-in: $U(1{)}_{B-3L_i}$ Gauged Extensions

    Basabendu Barman🇨🇴 · Purusottam Ghosh🇮🇳 · Anish Ghoshal🇵🇱 · Lopamudra Mukherjee🇺🇸

    We consider a singlet fermionic dark matter (DM) $\chi$ in a gauged $U(1{)}_{B-3L_i}$ extension of the Standard Model (SM), with $i\in e,\mu ,\tau$, and derive bounds on the allowed parameter space, considering its production via freeze-in mechanism. The DM communicates with the SM only through flavorful vector-portal $Z_{\text{B3L}}$ due to its non-trivial charge $x$ under $U(1{)}_{B-3L_i}$, which also guarantees the stability of the DM over the age of the Universe for $x\ne \{\pm 3/2,\pm 3\}$. Considering $Z_{\text{B3L}}$ to lie within the mass range of a few MeV up to a few GeV, we obtain constraints on the gauge coupling $g_{\text{B3L}}$ from the requirement of producing right relic abundance. Taking limits from various (present and future) experimental facilities, e.g., NuCal, NA64, FASER, SHiP into account, we show that the relic density allowed parameter space for the frozen in DM can be probed with $g_{\text{B3L}}\gtrsim 10^{-8}$ for both $m_{\chi }<m_{\text{ZB3L}}/2$ and $m_{\chi }\gtrsim m_{\text{ZB3L}}$, while $g_{\text{B3L}}\lesssim 10^{-8}$ remains mostly unconstrained. We also briefly comment on the implications of neutrino mass generation via Type-I seesaw and anomalous $(g-2{)}_{\mu }$ in context with $B-3L_{\mu }$ gauged symmetry.

    hep-phJCAP(2022)·19 citations
33. 33*

    Quantum vortex instability and black hole superradiance

    Sam Patrick🇨🇦 · August Geelmuyden🇬🇧 · Sebastian Erne🇦🇹 · Carlo F. Barenghi🇬🇧 · Silke Weinfurtner🇬🇧

    Vortices and black holes set the scene for many interesting dynamical processes in physics. Here, we study the dynamical instability of quantised vortices and rotational superradiance around rotating black holes, illustrating in the process that the same physics is at play in these two seemingly disparate phenomena. We also compare the instability of the vortex to the black hole bomb instability, which occurs for massive scalar fields in the Kerr spacetime. Taking inspiration from the analogy between black hole bomb modes and the hydrogen spectrum, the vortex instability is compared with nuclear resonances involved in $\alpha$-decay.

    ↳ cond-mat.quant-gasgr-qchep-phhep-thPRResearch(2022)·24 citations
34. 34*

    Warm inflation with bulk viscous pressure for different solutions of an anisotropic universe

    Mehdi Shokri🇮🇷 · Jafar Sadeghi🇮🇷 · Ramón Herrera🇨🇱 · Saeed Noori Gashti🇮🇷

    We study a warm inflationary model for different expansions assuming an anisotropic universe described by Bianchi I metric. The universe is filled with a scalar field or inflaton, radiation, and bulk viscous pressure. We carry out the inflationary analysis for different solutions of such universe in two different cases of the bulk viscosity coefficient $\xi$ and the dissipation coefficient $\Gamma$ as constant and variable parameters, respectively. We compare the obtained results with the recent observations, in order to find the observational constraints on the parameters space of the models. Moreover, we attempt to present a better judgment among the considered models by calculation of the non-linear parameter $f_{NL}$ describing the non-Gaussianity property of the models. Additionally, we investigate the warm inflationary models with viscous pressure from the Weak Gravity Conjecture approach, considering the swampland criteria.

    ↳ gr-qcastro-ph.COhep-phPhys.Scripta(2024)·13 citations
35. 35*

    Massive On-shell Recursion Relations for n-point Amplitudes

    Chao Wu🇨🇳 · Shou-Hua Zhu🇨🇳

    We construct two and three-line shifts for tree-level amplitude with massless and/or massive particles, and provide a method to construct general multi-line shifts for all masses. We choose the massless-massive BCFW shift from these shifts and examine its validity in renormalizable theories. Using such a shift, we find that amplitudes with at least one massless vector boson are constructible. This reveals the importance of gauge theory in the construction of amplitudes with massive particles. We also find that this kind of amplitudes have a cancellation related to group structure among different channels, which is essential for constructibility. Furthermore, we show that in the limit of large shift parameter $z$, the amplitude with four massive vector bosons, which can include transverse massive vector particles, have structures proportional to the amplitude with shifted vector particles replaced by Goldstone bosons in the leading order. This is responsible for the failure of massive-massive BCFW recursion relations in the amplitudes with four massive vector bosons.

    ↳ hep-thhep-phJHEP(2022)·21 citations
36. 36*

    Generalization capabilities of neural networks in lattice applications

    Srinath Bulusu🇦🇹 · Matteo Favoni🇦🇹 · Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Daniel Schuh🇦🇹

    In recent years, the use of machine learning has become increasingly popular in the context of lattice field theories. An essential element of such theories is represented by symmetries, whose inclusion in the neural network properties can lead to high reward in terms of performance and generalizability. A fundamental symmetry that usually characterizes physical systems on a lattice with periodic boundary conditions is equivariance under spacetime translations. Here we investigate the advantages of adopting translationally equivariant neural networks in favor of non-equivariant ones. The system we consider is a complex scalar field with quartic interaction on a two-dimensional lattice in the flux representation, on which the networks carry out various regression and classification tasks. Promising equivariant and non-equivariant architectures are identified with a systematic search. We demonstrate that in most of these tasks our best equivariant architectures can perform and generalize significantly better than their non-equivariant counterparts, which applies not only to physical parameters beyond those represented in the training set, but also to different lattice sizes.

    ↳ hep-latcs.LGhep-phstat.MLPoS(2022)·0 citations
37. 37*

    Equivariance and generalization in neural networks

    Srinath Bulusu🇦🇹 · Matteo Favoni🇦🇹 · Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Daniel Schuh🇦🇹

    The crucial role played by the underlying symmetries of high energy physics and lattice field theories calls for the implementation of such symmetries in the neural network architectures that are applied to the physical system under consideration. In these proceedings, we focus on the consequences of incorporating translational equivariance among the network properties, particularly in terms of performance and generalization. The benefits of equivariant networks are exemplified by studying a complex scalar field theory, on which various regression and classification tasks are examined. For a meaningful comparison, promising equivariant and non-equivariant architectures are identified by means of a systematic search. The results indicate that in most of the tasks our best equivariant architectures can perform and generalize significantly better than their non-equivariant counterparts, which applies not only to physical parameters beyond those represented in the training set, but also to different lattice sizes.

    ↳ hep-latcs.LGhep-phstat.MLEPJ Web Conf.(2022)·6 citations
38. 38*

    Electrical conductivity of the quark-gluon plasma from the low energy limit of photon and dilepton spectra

    Stefan Floerchinger🇩🇪 · Charlotte Gebhardt🇩🇪 · Klaus Reygers🇩🇪

    Fluid dynamic considerations are used to determine the electric current spectral density in the regime of small energies and momenta. The spectral density in this regime is parameterized by the electric conductivity, the charge susceptibility, and the relaxation time for the electric current, which is needed for relativistic causality. Experimentally, the spectral function can be accessed through the production rates of photons and dileptons in the expanding quark-gluon plasma. We use fluid dynamic simulations of high energy nuclear collisions, together with the transport limit of the spectral density, to obtain photon and dielectron spectra for different values of the conductivity and relaxation times. The yields of photon and dileptons produced in the plasma are compared to the background from decays of short-lived hadrons. We discuss how experiments can constrain the electrical conductivity and associated relaxation time of the quark-gluon plasma.

    ↳ nucl-thhep-phnucl-exPLB(2023)·18 citations
39. 39*

    Causal Temporal Renormalisation Group Flow of the Energy-Momentum Tensor

    Markus Heller🇩🇪 · Jan M. Pawlowski🇩🇪

    We derive the temporal renormalisation group flow of the energy-momentum tensor at the example of a general scalar theory. The local causal structure of the temporal renormalisation group flow allows to monitor and control causality, unitarity and general conservation laws at each infinitesimal renormalisation group step. We explore energy-conserving truncations in a comparison of generic flows and the causal temporal flow of the energy-momentum tensor. We also observe that the temporal regulator preserves scale invariance, which is violated for generic momentum regulators. Specifically we discuss the relation of these terms to the trace anomaly of the energy-momentum tensor. Moreover, we show that the causal temporal flow of the energy-momentum tensor can be integrated analytically, and demonstrate, that the result is consistent with energy conservation.

    ↳ hep-thcond-mat.othercond-mat.stat-mechhep-ph11 citations
40. 40*

    Relativistic Hydrodynamics: A Singulant Perspective

    Michal P. Heller🇩🇪 · Alexandre Serantes🇫🇮 · Michał Spaliński🇵🇱 · Viktor Svensson🇩🇪 · Benjamin Withers🇬🇧

    There is growing evidence that the hydrodynamic gradient expansion is factorially divergent. We advocate for using Dingle's singulants as a way to gain analytic control over its large-order behaviour for nonlinear flows. Within our approach, singulants can be viewed as new emergent degrees of freedom which reorganise the large-order gradient expansion. We work out the physics of singulants for longitudinal flows, where they obey simple evolution equations which we compute in Müller-Israel-Stewart-like models, holography and kinetic theory. These equations determine the dynamics of the large-order behaviour of the hydrodynamic expansion, which we confirm with explicit numerical calculations. One of our key findings is a duality between singulant dynamics and a certain linear response theory problem. Finally, we discuss the role of singulants in optimal truncation of the hydrodynamic gradient expansion. A by-product of our analysis is a new Müller-Israel-Stewart-like model, where the qualitative behaviour of singulants shares more similarities with holography than models considered hitherto.

    ↳ hep-thhep-phnucl-thphysics.flu-dynPRX(2022)·30 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.