Fri·Apr 22, 2022Friday·April 22, 2022

1. 01*

   Pseudorapidity dependence of the $p_T$ spectra of charged hadrons in $pp$ collisions at $\sqrt{s}$ = 0.9 and 2.36 TeV

   Pei-Pin Yang🇨🇳 · Muhammad Ajaz🇵🇰 · Muhammad Waqas🇨🇳 · Fu-Hu Liu🇨🇳 · Mais K. Suleymanov🇦🇿

   We report the predictions of different Monte Carlo event generators including HIJING, Pythia, and QGSJETII in comparison with the experimental data measured by the CMS Collaboration at CERN in proton-proton ($pp$) collisions at center-of-mass energy $\sqrt{s}$ = 0.9 and 2.36 TeV. The CMS experimental transverse momentum ($p_T$ or $p_{\perp }$) spectra of charged hadrons were measured for pseudorapidity range 0 $\le$ $\eta$ $\le$ 2.4 with bin width of $\eta$ = 0.2 (for $p_T$ from 0.1 to 2 GeV/$c$) and a single bin of $\eta$ for $|$$\eta$$|$ $<$ 2.4 (for $p_T$ from 0.1 to 4 GeV/$c$). Pythia reproduced the $p_T$ spectra with reasonable agreement for most of the $p_T$ range. It depicts better results in the case of the $|\eta |<$ 2.4 than HIJING and QGSJETII which could reproduce the spectra in a limited $p_T$ range. Furthermore, to analyze the $p_T$ spectra of charged hadrons measured by the CMS Collaboration, we used a three component function (structured from the Boltzmann distribution) and the $q$-dual function (from the $q$-dual statistics) to extract parameter values relevant for the study of bulk properties of hadronic matter at high energy. We have also applied the two analytic functions over the model predictions. The values extracted by the functions from the HIJING and Pythia models are closer to the experimental data than the QGSJETII model. Although the models could reproduce the $p_T$ spectra of all charged particles in some of the $p_T$ range but none of them could reproduce the distributions over the entire $p_T$ range and in all the pseudorapidity regions.

   hep-phJ.Phys.G(2022)·24 citations
2. 02*

   Time-like Gravitational Formfactors and Shear Viscosity

   Oleg Teryaev🇷🇺

   The gravitational formfactor similar to shear viscosity is identified. In the time-like region it corresponds to the contribution of exotic hybrid meson. The exotic quantum numbers may be considered as a counterpart of dissipation in crossed channel. The ratio of viscosity to entropy density is estimated. The smallness due to holographic bound corresponds to the relative smallness of coupling of hybrid meson and the intrinsic transverse momentum, being the dynamical counterpart of temperature.

   hep-phgr-qcnucl-thJPS Conf.Proc.(2022)·5 citations
3. 03*

   The Higgs boson as a self-similar system: Towards a new solution to the hierarchy problem

   M. Ahmadvand🇮🇷

   We propose a new solution to the hierarchy (naturalness) problem, concerning quantum corrections of the Higgs mass. Assuming the Higgs boson as a system with a self-similar internal structure, we calculate its two-point function and find that the quadratic divergence is replaced by a logarithmic one in the mass corrections. It is shown that the partonic-like distribution follows the Tsallis statistics and also high energy physics experimental data for the Higgs transverse momentum distribution can be described by a self-similar statistical model.

   hep-phhep-exhep-th2 citations
4. 04*

   Double parton scattering via photon-proton interactions: a new light on the transverse proton structure

   Rinaldi Matteo🇮🇹

   In this contribution we present the main results of the investigation about double parton scattering (DPS) in quasi-real photon-proton interactions. We show the first evaluation of the DPS cross-section at leading-order for the four-jet photo-production observed at HERA. To this aim the $\gamma -p$ effective cross section has been computed for the first time. One of the main outcomes of this analysis is that the DPS contribution is not negligible and potentially measurable. Furthermore, possible future data could be used to get new information on the transverse proton structure not accessible in other processes.

   hep-phRev.Mex.Fis.Suppl.(2022)·0 citations
5. 05*

   The pion in the graviton soft-wall model: phenomenological applications

   M. Rinaldi🇮🇹 · F. A. Ceccopieri🇫🇷 · V. Vento🇪🇸

   The holographic graviton soft-wall model, introduced to describe the spectrum of scalar and tensor glueballs, is improved to incorporate the realization of chiral-symmetry as in QCD. Such a goal is achieved by including the longitudinal dynamics of QCD into the scheme. Using the relation between AdS/QCD and Light-Front dynamics, we construct the appropriate wave function for the pion which is used to calculate several pion observables. The comparison of our results with phenomenology is remarkably successful.

   hep-phEPJC(2022)·21 citations
6. 06*

   Implication of the dark axion portal for the EDM of fermions and dark matter probing with NA64$e$, NA64$\mu$, LDMX, $\text{mbox}{M}^3$, and BaBar

   Alexey S. Zhevlakov🇷🇺 · Dmitry V. Kirpichnikov🇷🇺 · Valery E. Lyubovitskij🇩🇪

   The link between ordinary Standard model (SM) photon and both dark photon and axion like particle (ALP) can be introduced through the dark axion portal coupling. Given the dark axion portal setup, in the present paper we refer the dark photon as the mediator between SM and dark matter (DM) particles, implying that it decays predominantly into pair of DM fermions. Furthermore, we discuss in detail the implication of the dark axion portal scenario for the lepton (electron and muon) fixed target experiments. In particular, for the specific fixed target facility we study the missing energy signatures of the dark photon production followed by its invisible decay into stable DM particles. We investigated the potential to probe dark axion portal vertices with regarding signatures and derive the expected sensitivities of NA64$e$, NA64$\mu$, LDMX and $\text{mbox}{M}^3$. Moreover, we estimated the expected reach of NA64$e$ from the projected statistics of the $J/\psi$ vector meson invisible decays. We also recasted BaBar monophoton bounds for the specific dark axion portal scenario. In addition, we modified the dark axion portal setup by including in the model both the hadron and lepton specific ALP couplings. As the result, we obtain the bounds on the combination of fermion-specific couplings of ALP from the fixed target experiments. We discuss the implication of the modified dark axion portal scenario for the electric dipole moments (EDM) of SM fermions. In addition, we derived the novel constraints on the combination of the $CP$-violating neutron-specific ALP couplings from the existing bounds on neutron EDM by taking into account the neutron anomalous magnetic moment.

   hep-phPRD(2022)·31 citations
7. 07*

   Impact of heavy quark and quarkonium data on nuclear gluon PDFs

   P. Duwentäster🇩🇪 · T. Ježo🇩🇪 · M. Klasen🇩🇪 · K. Kovařík🇩🇪 · A. Kusina🇵🇱 · K.F. Muzakka🇩🇪 · F.I. Olness🇺🇸 · R. Ruiz🇵🇱 · I. Schienbein🇫🇷 · J.Y. Yu🇫🇷

   A clear understanding of nuclear parton distribution functions (nPDFs) plays a crucial role in the interpretation of collider data taken at the Relativistic Heavy Ion Collider (RHIC), the Large Hadron Collider (LHC) and in the near future at the Electron-Ion Collider (EIC). Even with the recent inclusions of vector boson and light meson production data, the uncertainty of the gluon PDF remains substantial and limits the interpretation of heavy ion collision data. To obtain new constraints on the nuclear gluon PDF, we extend our recent nCTEQ15WZ+SIH analysis to inclusive quarkonium and open heavy-flavor meson production data from the LHC. This vast new data set covers a wide kinematic range and puts strong constraints on the nuclear gluon PDF down to $x\lesssim 10^{-5}$. The theoretical predictions for these data sets are obtained from a data-driven approach, where proton-proton data are used to determine effective scattering matrix elements. This approach is validated with detailed comparisons to existing next-to-leading order (NLO) calculations in non-relativistic QCD (NRQCD) for quarkonia and in the general-mass variable-flavor-number scheme (GMVFNS) for the open heavy-flavored mesons. In addition, the uncertainties from the data-driven approach are determined using the Hessian method and accounted for in the PDF fits. This extension of our previous analyses represents an important step toward the next generation of PDFs not only by including new data sets, but also by exploring new methods for future analyses.

   hep-phPRD(2022)·82 citations
8. 08*

   Measuring the anomalous quartic gauge couplings in the $W^{+}{W}^{-}\to W^{+}{W}^{-}$ process at muon collider using artificial neural networks

   Ji-Chong Yang🇨🇳 · Xue-Ying Han🇨🇳 · Zhi-Bin Qin🇨🇳 · Tong Li🇨🇳 · Yu-Chen Guo🇨🇳

   The muon collider provides a unique opportunity to study the vector boson scattering processes and dimension-8 operators contributing to anomalous quartic gauge couplings~(aQGCs). Because of the cleaner final state, it is easier to decode subprocess and certain operator couplings at a muon collider. We attempt to identify the anomalous $WWWW$ coupling in the exclusive $WW\to WW$ scattering in this paper. Since one aQGC can be induced by multiple dimension-8 operators, the study of one coupling can help to confine different operators. Meanwhile, singling out the $WW\to WW$ process can help to study the unitarity bounds. The vector boson scattering process corresponding to the anomalous $WWWW$ coupling is ${\mu }^{+}{\mu }^{-}\to \nu \nu \bar{\nu }\bar{\nu }{\ell }^{+}{\ell }^{-}$, with four (anti-)neutrinos in the final state, which brings troubles in phenomenological studies. In this paper, the machine learning method is used to tackle this problem. We find that, using the artificial neural network can extract the $W^{+}{W}^{-}\to W^{+}{W}^{-}$ contribution, and is helpful to reconstruct the center of mass energy of the subprocess which is important in the study of the Standard Model effective field theory. The sensitivities and the expected constraints on the dimension-8 operators at the muon collider with $\sqrt{s}=30$ TeV are presented. We demonstrate that the artificial neural networks exhibit great potential in the phenomenological study of processes with multiple neutrinos in the final state.

   hep-phJHEP(2022)·32 citations
9. 09*

   Mass spectra of ${\Xi }_{cc}$, ${\Xi }_{bc}$, ${\Omega }_{cc}$, and ${\Omega }_{bc}$ baryons in Regge Phenomenology

   Juhi Oudichhya🇮🇳 · Keval Gandhi🇮🇳 · Ajay Kumar Rai🇮🇳

   In this article, we study the mass spectra of baryons containing two heavy quarks; charm-charm ($cc$) and bottom-charm ($bc$) with a light quark ($u,d,s$) within the framework of Regge phenomenology. With the assumption of linear Regge trajectories we have derived the relations between slope ratios, intercepts, and baryon masses. Using these relations, the ground state masses of ${\Xi }_{cc}$, ${\Xi }_{bc}$, ${\Omega }_{cc}$, and ${\Omega }_{bc}$ baryons are obtained. The values of Regge slopes and Regge intercepts are extracted for these baryons to estimate the excited state masses in both the ($J,M^2$) and ($n,M^2$) planes. Our obtained results are compared with the experimental observations where available and other theoretical predictions, which could be a valuable addition to the interpretations of experimentally unknown heavy baryon spectra.

   hep-phPhys.Scripta(2022)·31 citations
10. 10*

    Medium modification of the nucleon mechanical properties: Abel tomography case

    June-Young Kim🇩🇪 · Ulugbek Yakhshiev🇰🇷 · Hyun-Chul Kim🇰🇷

    We investigate how the gravitational form factors of the nucleon undergo changes in nuclear matter, emphasizing the Abel transformation from the three-dimensional (3D) Breit frame to the two-dimensional (2D) light-front frame. Since the gravitational form factors reveal the mechanical structure of the nucleon, we examine also the medium modifications of the energy-momentum, pressure, and shear-force distributions. We scrutinize the stabilities of the nucleon in nuclear matter. For this purpose, we employ the in-medium modified SU(2) Skyrme model to study these mechanical quantities of the nucleon, since it provides a simple but clear framework. In this in-medium modified SU(2) Skyrme model, the modification of pionic properties is performed by using low-energy pion-nucleus scattering data and the saturation properties of nuclear matter near the normal nuclear matter density, ${\rho }_0=0.5m_{\pi }^3$. The results reveal how the nucleon swells in nuclear matter as the mass distribution of the nucleon is broadened in medium. We also show that the mean square radii corresponding to the mass and angular momentum distributions increase in nuclear medium. This feature is kept both in 3D and 2D cases. We visualize how the strong force fields inside the nucleon in the 2D plane are distributed and illustrate how these forces undergo change in nuclear matter.

    hep-phhep-exnucl-exnucl-thEPJC(2022)·8 citations
11. 11*

    The ReBB model and its $H(x)$ scaling version at 8 TeV: Odderon exchange is a certainty

    I. Szanyi🇭🇺 · T. Csörgő🇭🇺

    The Real Extended Bialas-Bzdak (ReBB) model is shown here to describe, in the $0.37\le -t\le 1.2$ GeV${}^2$ region, the proton-proton elastic differential cross section data published by the TOTEM Collaboration at LHC at $\sqrt{s}=8$ TeV center of mass energy. In this kinematic range, corresponding to the diffractive minimum-maximum region, a model-dependent Odderon signal higher than 18 $\sigma$ is obtained by comparing the ReBB model prediction for the $p\bar{p}$ elastic differential cross section to this TOTEM measured $pp$ elastic differential cross section data at 8 TeV. However, when combining this signal with the Odderon signals from the ReBB model in the $0.37\le -t\le 1.2$ GeV${}^2$ four-momentum-transfer range at $\sqrt{s}=$ 1.96, 2.76 and 7 TeV, it turns out that the combined significance is dominated not by the new 8 TeV but by that of earlier 7 TeV TOTEM data, that carry an even larger Odderon effect. Thus, in any practical terms, within the framework of the ReBB model, the Odderon signal in the limited $0.37\le -t\le 1.2$ GeV${}^2$ and $1.96\le \sqrt{s}\le 8$ TeV kinematic region is not a probability, but a certainty. We show also that the $H(x)$ scaling version of the ReBB model works reasonably well at 8 TeV in the $0.37\le -t\le 0.97$ GeV${}^2$ region.

    hep-phEPJC(2022)·8 citations
12. 12*

    Multicomponent second-order dissipative relativistic hydrodynamics with binary reactive collisions

    Jin Hu🇨🇳 · Shuzhe Shi🇺🇸

    We derive the multi-component second-order dissipative relativistic hydrodynamic equations using the moment-expansion method. By computing the transport coefficients using hard-sphere interactions, we investigate the role of multiple components and the reactive collisions. We find that both of these factors increase the effective cross-section and hence decrease the transport coefficients and relaxation times. We further compute such transport properties using leading-order perturbative QCD cross-sections. For both types of cross-sections, we find that the ratio between vector current relaxation time and conductivity for a multi-component fluid is notably different from that for a single-component fluid. Therefore, the current study provides a more applicable guideline for such a ratio in phenomenological hydrodynamics simulations.

    hep-phnucl-thPRD(2022)·15 citations
13. 13*

    An analytical solution of Balitsky-Kovchegov equation using homotopy perturbation method

    Ranjan Saikia🇮🇳 · Pragyan Phukan🇮🇳 · Jayanta Kumar Sarma🇮🇳

    An approximate analytical solution of the Balitsky-Kovchegov (BK) equation using the homotopy perturbation method (HPM) is suggested in this work. We have carried out our work in perturbative QCD (pQCD) dipole picture of deep inelastic scattering (DIS). The BK equation in momentum space with some change of variables and truncation of the BFKL (Balitsky-Fadin-Kuraev-Lipatov) kernel can be reduced to the FKPP (Fisher-Kolmogorov-Petrovsky-Piscounov) equation [Munier and Peschanski 2003]. The observed geometric scaling phenomena are similar to the travelling wave solution of the FKPP equation. We solved the BK equation using the HPM. The obtained solution in this work also suggests the travelling wave nature of the measured scattering amplitude N(k, Y) plotted at various rapidities. The result obtained in this work can be helpful for different phenomenological studies in high-density QCD.

    hep-phInt.J.Mod.Phys.A(2022)·4 citations
14. 14*

    Deviation from Tribimaximal mixing using $A_4$ flavour model with five extra scalars

    Victoria Puyam🇮🇳 · S.Robertson Singh🇮🇳 · N. Nimai Singh🇮🇳

    A modified neutrino mass model with five extra scalars is constructed using $A_4$ discrete symmetry group. The resultant mass matrix is able to give necessary deviation from Tribimaximal mixing which reproduces the current neutrino masses and mixing data with good accuracy. The model gives testable prediction for the future measurements of the neutrinoless double-beta decay parameter $|m_{\beta \beta }|$. The analysis is consistent with latest cosmological bound $\Sigma m_i\le$ 0.12 eV.

    hep-phNPB(2022)·10 citations
15. 15*

    Impact of CDF-II measurement of $M_W$ on the electroweak legacy of the LHC Run II

    Eduardo da Silva Almeida🇧🇷 · Alexandre Alves🇧🇷 · Oscar J. P. Eboli🇧🇷 · M. C. Gonzalez-Garcia🇪🇸

    We analyze the impact of the recently released CDF-II measurement of $W$ mass on the SMEFT analyses of the electroweak precision data as well as Higgs and electroweak diboson productions. We work in the Hagiwara, Ishihara, Szalapski, and Zeppenfeld basis in which eight generation-independent operators enter in the electroweak precision data at tree level and, unlike in the Warsaw basis, the analysis of that set of data constrains all the eight Wilson coefficients, without the need of combination with Higgs or electroweak diboson data results. We show that in the global analysis the determination of the coefficients of all operators which do not enter the electroweak precision data are barely affected by the new $M_W$ determination.

    hep-ph25 citations
16. 16*

    Dark photon kinetic mixing effects for the CDF W-mass measurement

    Yu Cheng🇨🇳 · Xiao-Gang He🇨🇳 · Fei Huang🇨🇳 · Jin Sun🇨🇳 · Zhi-Peng Xing🇨🇳

    A new $U(1{)}_X$ gauge boson $X$ primarily interacting with a dark sector can have renormalizable kinetic mixing with the standard model (SM) $U(1{)}_Y$ gauge boson $Y$. This mixing besides introduces interactions of dark photon and dark sector with SM particles, it also modifies interactions among SM particles. The modified interactions can be casted into the oblique $S$, $T$ and $U$ parameters. We find that with the dark photon mass larger than the $Z$ boson mass, the kinetic mixing effects can reduce the tension of the W mass excess problem reported recently by CDF from $7\sigma$ deviation to within $3\sigma$ compared with theory prediction. If there is non-abelian kinetic mixing between $U(1{)}_X$ and $SU(2{)}_L$ gauge bosons, in simple renormalizable models of this type a triplet Higgs is required to generate the mixing. We find that this triplet with a vacuum expectation value of order 5 GeV can naturally explain the W mass excess.

    hep-phPRD(2022)·58 citations
17. 17*

    NNLO QCD corrections in full colour for jet production observables at the LHC

    X. Chen🇩🇪 · T. Gehrmann🇨🇭 · E.W.N. Glover🇬🇧 · A. Huss🇨🇭 · J. Mo🇨🇭

    Calculations for processes involving a high multiplicity of coloured particles often employ a leading colour approximation, where only the leading terms in the expansion of the number of colours $N_c$ and the number of flavours $n_f$ are retained. This approximation of the full colour result is motivated by the $1/N_c^2$ suppression of the first subleading terms and by the increasing complexity of including subleading colour contributions to the calculation. In this work, we present the calculations using the antenna subtraction method in the NNLOJET framework for the NNLO QCD corrections at full colour for several jet observables at the LHC. The single jet inclusive cross section is calculated doubly differential in transverse momentum and absolute rapidity and compared with the CMS measurement at 13 TeV. A calculation for dijet production doubly differential in dijet mass and rapidity difference is also performed and compared with the ATLAS 7 TeV data. Lastly, a triply differential dijet cross section in average transverse momentum, rapidity separation and dijet system boost is calculated and compared with the CMS 8 TeV data. The impact of the subleading colour contributions to the leading colour approximation is assessed in detail for all three types of observables and as a function of the jet cone size. The subleading colour contributions play a potentially sizable role in the description of the triply differential distributions, which probe kinematical configurations that are not easily accessed by any of the other observables.

    hep-phJHEP(2022)·52 citations
18. 18*

    Experimentally distinguishable origin for electroweak symmetry breaking

    Victor Baules🇺🇸 · Nobuchika Okada🇺🇸

    We consider a classically conformal $U(1)$ gauge extension of the Standard Model (SM), in which the $U(1)$ gauge symmetry is radiatively broken by the Coleman-Weinberg mechanism. This breaking triggers the electroweak (EW) symmetry breaking through a mixed quartic coupling between the $U(1)$ Higgs field and the SM Higgs doublet. For two Higgs boson mass eigenstates after the symmetry breaking, $h_1$ (SM-like Higgs boson) and $h_2$ (SM singlet-like Higgs boson), we calculate the Higgs boson trilinear coupling ($g_{h_1{h}_2{h}_2}$) in the model by setting the Higgs boson mass spectrum to be $M_{h_1}>2M_{h_2}$. For a common Higgs mass spectrum and mixing angle between two Higgs fields, we find that $g_{h_1{h}_2{h}_2}$ in the classically conformal model is highly suppressed compared to that calculated for the conventional Higgs potential, where the $U(1)$ and EW symmetry breaking originate from the negative squared masses for the Higgs fields at the tree-level. Thus, this coupling suppression is a striking nature of the radiative origin of EW symmetry breaking. We then consider how to distinguish this origin at the proposed International Linear Collider (ILC) via precise measurements of anomalous SM Higgs boson couplings and the search for anomalous SM Higgs boson decay $h_1\to h_2{h}_2$ followed by $h_2\to b\bar{b}$. We conclude that once the anomalous couplings are measured at the ILC, the observation of the anomalous Higgs boson decay is promising in the conventional Higgs potential, while this decay process is highly suppressed and undetectable for the classically conformal model.

    hep-phhep-exPTEP·1 citation
19. 19*

    W-boson mass in the triplet seesaw model

    Julian Heeck🇺🇸

    The CDF collaboration has recently published a precision measurement of the W-boson mass that differs from the Standard Model prediction by seven standard deviations. This result can be explained with additional electroweak multiplets that either break the custodial symmetry or contribute to oblique parameters at loop level. Here, we study one of the best-motivated scenarios involving new multiplets: the type-II seesaw model, which involves a scalar triplet that generates Majorana neutrino masses and can furthermore resolve the W-boson mass discrepancy. This favors a doubly-charged scalar with mass between 100 and 200 GeV as well as other scalars with a fixed mass splitting. The entire preferred parameter space is testable at the LHC.

    hep-phhep-exPRD(2022)·57 citations
20. 20*

    CDF II $W$-mass anomaly faces first-order electroweak phase transition

    Andrea Addazi🇨🇳 · Antonino Marciano🇨🇳 · António P. Morais🇵🇹 · Roman Pasechnik🇸🇪 · Hao Yang🇨🇳

    We suggest an appealing strategy to probe a large class of scenarios beyond the Standard Model simultaneously explaining the recent CDF II measurement of the $W$ boson mass and predicting first-order phase transitions (FOPT) testable in future gravitational-wave (GW) experiments. Our analysis deploys measurements from the GW channels and high energy particle colliders. We discuss this methodology focusing on the specific example provided by an extension of the Standard Model of particle physics that incorporates an additional scalar $\mathrm{SU}(2{)}_{\mathrm{L}}$ triplet coupled to the Higgs boson. We show that within this scenario a strong electroweak FOPT is naturally realised consistently with the measured $W$ boson mass-shift. Potentially observable GW signatures imply the triplet mass scale to be TeV-ish, consistently with the value preferred by the $W$ mass anomaly. This model can be tested in future space-based interferometers such as LISA, DECIGO, BBO, TianQin, TAIJI projects and in future colliders such as FCC, ILC, CEPC.

    hep-phEPJC(2023)·34 citations
21. 21*

    Pion and kaon fragmentation functions at next-to-next-to-leading order

    Rabah Abdul Khalek🇺🇸 · Valerio Bertone🇫🇷 · Alice Khoudli🇫🇷 · Emanuele R. Nocera🇬🇧

    We present a new determination of unpolarised charged pion and kaon fragmentation functions from a set of single-inclusive electron-positron annihilation and lepton-nucleon semi-inclusive deep-inelastic scattering data. The determination includes next-to-next-to-leading order QCD corrections to both processes, and is carried out in a framework that combines a neural-network parametrisation of fragmentation functions with a Monte Carlo representation of their uncertainties. We discuss the quality of the determination, in particular its dependence on higher order corrections.

    hep-phhep-exPLB(2022)·89 citations
22. 22*

    On the Superiority of the $|V_{cb}|-\gamma$ Plots over the Unitarity Triangle Plots in the 2020s

    Andrzej J. Buras🇩🇪

    The UT plots played already for three decades an important role in the tests of the SM and the determination of the CKM parameters. As of 2022, among the four CKM parameters, $V_{us}$ and $\beta$ are already measured with respectable precision, while this is not the case of $|V_{cb}|$ and $\gamma$. In the case of $|V_{cb}|$ the main obstacle are the significant tensions between its inclusive and exclusive determinations from tree-level decays. The present uncertainty in $\gamma$ of $4^{\circ }$ from tree-level decays will be reduced to $1^{\circ }$ by the LHCb and Belle II collaborations in the coming years. Unfortunately in the UT plots $|V_{cb}|$ is not seen and the experimental improvements in the determination of $\gamma$ from tree-level decays at the level of a few degrees are difficult to appreciate. In view of these deficiencies of the UT plots with respect to $|V_{cb}|$ and $\gamma$ and the central role these two CKM parameters will play in this decade, the recently proposed plots of $|V_{cb}|$ versus $\gamma$ extracted from various processes appear to be superior to the UT plots in the flavour phenomenology. We illustrate this idea with $\Delta M_s$, $\Delta M_d$, ${ϵ}_K$ and with rare decays $B_s\to {\mu }^{+}{\mu }^{-}$, $B_d\to {\mu }^{+}{\mu }^{-}$, $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ and $K_L\to {\pi }^0\nu \bar{\nu }$. The power of ${ϵ}_K$, $K^{+}\to {\pi }^{+}\nu \bar{\nu })$ and $K_L\to {\pi }^0\nu \bar{\nu })$ in the determination of $|V_{cb}|$, due to their strong dependence on $|V_{cb}|$, is transparently exhibited in this manner. Combined with future reduced errors on $\gamma$ and $|V_{cb}|$ from tree-level decays such plots can better exhibit possible inconsistenices between various determinations of these two parameters, caused by new physics, than it is possible with the UT plots.

    hep-phhep-exhep-latEPJC(2022)·12 citations
23. 23*

    Status of the two-Higgs-doublet model in light of the CDF $m_W$ measurement

    Soojin Lee🇰🇷 · Kingman Cheung🇹🇼 · Jinheung Kim🇰🇷 · Chih-Ting Lu🇨🇳 · Jeonghyeon Song🇰🇷

    The most recent $W$-boson mass measurement by the CDF collaboration with a substantially reduced uncertainty indicates a significant deviation from the standard model prediction, as large as $7\sigma$ if taken literally. Then the Peskin-Takeuchi parameters of $S$ and $T$ shift to larger values, which has profound consequences in searching for physics beyond the SM. In the framework of two-Higgs-doublet models, we study the effect of the new $W$-boson mass measurement on the parameter space. Combined with other constraints including theoretical requirements, flavor-changing neutral currents in $B$ physics, the cutoff scale above 1 TeV, Higgs precision data, and direct collider search limits from the LEP, Tevatron, and LHC experiments, we find upper bounds on the masses of the heavy Higgs bosons: $M_{H,A,H^{\pm }}\lesssim 1.1$ TeV in type I, II, X, and Y for the normal Higgs scenario; $M_{H^{\pm }}\lesssim 450$ GeV and $M_A\lesssim 420$ GeV in type I and X for the inverted scenario where the heavier $CP$-even Higgs boson is the observed one. Another important finding is that type II and type Y in the inverted scenario are completely excluded. Such unprecedented findings imply that the upcoming LHC run can readily close out a large portion of the still-available parameter space.

    hep-phhep-exPRD(2022)·68 citations
24. 24*

    Cogenesis of Baryon Asymmetry and Gravitational Dark Matter from Primordial Black Holes

    Basabendu Barman🇨🇴 · Debasish Borah🇮🇳 · Suruj Jyoti Das🇮🇳 · Rishav Roshan🇰🇷

    We propose a scenario where dark matter (DM) with a wide mass range from a few keV to PeV can be produced solely from evaporating primordial black holes (PBH), while being consistent with the required free streaming length for structure formation. If DM does not have any other interactions apart from gravity and the universe has a PBH dominated phase at early epoch, then PBH evaporation typically leads to overproduction of DM in this mass range. By incorporating this gravitational DM within a Type-I seesaw scenario with three right handed neutrinos (RHN), we bring the abundance of PBH generated DM within observed limits by late entropy injection due to decay of one of the RHNs, acting as the diluter. The diluter, due to its feeble coupling with the bath particles, gets produced primarily from the PBH evaporation thereby leading to the second stage of early matter domination after the end of PBH dominated era. The other two RHNs contribute to the origin of light neutrino mass and also lead to the observed baryon asymmetry via leptogenesis with contributions from both thermally and PBH generated RHNs. The criteria of DM relic and baryon asymmetry can be satisfied simultaneously if DM mass gets restricted to a ballpark in the MeV-GeV regime with the requirement of resonant leptogenesis for heavier DM mass in order to survive the large entropy dilution at late epochs.

    hep-phJCAP(2022)·34 citations
25. 25*

    Dynamical relaxation of cosmological constant

    M.Yoshimura🇯🇵

    A special class of conformal gravity theories is proposed to solve the long standing problem of the fine-tuned cosmological constant. In the proposed model time evolution of the inflaton field leaves behind a nearly vanishing, but finite value of dark energy density of order (a few meV)${}^4$ to explain the late-time accelerating universe. A multiple scalar inflaton field is assumed to have a conformal coupling to the Ricci scalar curvature in the lagrantian, which results in, after a Weyl rescaling to the Einstein metric frame, modification of inflaton kinetic and potential terms along with its coupling to Higgs fields in the standard model. One may define an effective cosmological $\Lambda$ function in the Einstein metric frame, which controls, when the potential is added, a slow-roll inflation and subsequent oscillation at the potential minimum of a spontaneous symmetry breaking phase. The inflaton oscillation accompanies particle production towards thermalized hot big-bang universe. At the same time zero-point quantum fluctuation of second inflaton field is generated,and its accumulated fluctuation gives rise to a symmetry restoration, pushing back the inflaton field towards the infinity. This gives a dynamical relaxation of vanishing effective cosmological constant. Both inhomogeneous inflaton modes and their collapsed black holes of primordial origin are good candidates of cold dark matter.

    hep-phastro-ph.COgr-qchep-th4 citations
26. 26*

    Thawing k-essence dark energy in the PAge space

    Zhiqi Huang🇨🇳

    A broad class of dark energy models can be written in the form of k-essence, whose Lagrangian density is a two-variable function of a scalar field $\varphi$ and its kinetic energy $X\equiv \frac{1}{2}{\partial }^{\mu }\varphi {\partial }_{\mu }\varphi$. In the thawing scenario, the scalar field becomes dynamic only when the Hubble friction drops below its mass scale in the late universe. Thawing k-essence dark energy models can be randomly sampled by generating the Taylor expansion coefficients of its Lagrangian density from random matrices \cite{thaws}. Ref. \cite{thaws} points out that the non-uniform distribution of effective equation of state parameters $(w_0,w_a)$ of thawing k-essence model can be used to improve the statistics of model selection. The present work studies the statistics of thawing k-essence in a more general framework that is Parameterized by the Age of the universe (PAge) \cite{PAge}. For fixed matter fraction ${\Omega }_m$, the random thawing k-essence models cluster in a narrow band in the PAge parameter space, providing a strong theoretical prior. We simulate cosmic shear power spectrum data for the Chinese Space Station Telescope optical survey, and compare the fisher forecast with and without the theoretical prior of thawing k-essence. For an optimal tomography binning scheme, the theoretical prior improves the figure of merit in PAge space by a factor of $3.3$.

    ↳ astro-ph.COgr-qchep-phhep-thCommun.Theor.Phys.(2022)·8 citations
27. 27*

    An updated view and perspectives on high-energy gamma-ray emission from SGR J1935+2154 and its environment

    Jaziel G. Coelho🇧🇷 · Luana N. Padilha🇧🇷 · Rita C. dos Anjos🇧🇷 · Cynthia V. Ventura🇧🇷 · Geanderson A. Carvalho🇧🇷

    SGR J1935+2154 was discovered in 2016 and is currently one of the most burst-active Soft Gamma-ray Repeaters (SGR), having emitted several X-ray bursts in recent years. In one of our previous articles, we investigated the contribution to high-energy and very high-energy gamma-ray emission (VHE, $E>100$ GeV) due to cosmic-ray acceleration of SNR G57.2+0.8 hosting SGR J1935+2154 using the GALPROP propagation code. However, follow-up observations of SGR 1935+2154 were made for 2 hours on April 28, 2020, using the High Energy Stereoscopic System (H.E.S.S.). The observations coincide with X-ray bursts detected by INTEGRAL and Fermi/Gamma-ray Burst Monitor (GBM). These are the first high-energy gamma-ray observations of an SGR in a flaring state, and upper limits on sustained and transient emission have been derived. Now that new H.E.S.S. observations have been made, it is interesting to update our model with respect to these new upper limits. We extend our previous results to a more general situation using the new version of GALPROP. We obtain a hadronic model that confirms the results discussed by H.E.S.S.. This leads to an optimistic prospect that cosmic ray gamma rays from SGR J1935+2154 can contribute to the overall gamma energy density distribution and in particular to the diffusion gamma rays from the Galactic center.

    ↳ astro-ph.HEastro-ph.SRhep-phhep-thJCAP(2022)·7 citations
28. 28*

    Effect of various particlization scenarios on anisotropic flow and particle production using UrQMD hybrid model

    Sumit Kumar Kundu🇮🇳 · Yoshini Bailung🇮🇳 · Sudhir Pandurang Rode🇷🇺 · Partha Pratim Bhaduri🇮🇳 · Ankhi Roy🇮🇳

    We discuss the effect of various particlization scenarios available in the hybrid ultrarelativistic quantum molecular dynamics (UrQMD) event generator on different observables in non-central ($b$ $=$ 5--9 $fm$) Au + Au collisions in the beam energy range 1A-158A GeV. Particlization models switch fluid dynamic description to the transport description using various hypersurface criteria. In addition to particlization models, various equations-of-state (EoS) provided by the UrQMD hybrid model were employed. The observables examined in this paper include the excitation function of anisotropic coefficients such as directed ($v_1$) and elliptic flow ($v_2$), particle ratios of the species, and the shape of net-proton rapidity spectra at mid-rapidity. The results obtained here can help predict and compare the measurements provided by future experiments at the Facility for Antiproton and Ion Research (FAIR) and the Nuclotron-based Ion Collider fAcility (NICA) once the data becomes available. We also study the most suitable combination of the particlization model and EoS, which best describes the experimental measurements.

    ↳ nucl-thhep-phNPA(2023)·1 citation
29. 29*

    Ultraviolet Finiteness or Asymptotic Safety in Higher Derivative Gravitational Theories

    Leslaw Rachwal🇧🇷

    We present and discuss well known conditions for ultraviolet finiteness and asymptotic safety. The requirements for complete absence of ultraviolet divergences in quantum field theories and existence of a non-trivial fixed point for renormalization group flow in the ultraviolet regime are compared based on the example of a six-derivative quantum gravitational theory in $d=4$ spacetime dimensions. In this model, it is possible for the first time to have fully UV-finite quantum theory without adding matter or special symmetry, but by inclusion of additional terms cubic in curvatures. We comment on similarities and some apparent differences between the two approaches, but we show that they are both compatible to each other. Finally, we motivate the claim that actually asymptotic safety needs UV-finite models for providing explicit form of the ultraviolet limit of Wilsonian effective actions describing special situations at fixed points.

    ↳ hep-thgr-qchep-phmath-ph+2Universe(2022)·4 citations
30. 30*

    Measurement of the effective weak mixing angle at the CEPC

    Zhenyu Zhao🇨🇳 · Siqi Yang🇨🇳 · Manqi Ruan🇨🇳 · Minghui Liu🇨🇳 · Liang Han🇨🇳

    We present a study of the measurement of the effective weak mixing angle parameter (${\sin }^2{\theta }_{\text{eff}}^{\ell }$) at the Circular Electron Positron Collider (CEPC). As a fundamental physics parameter, ${\sin }^2{\theta }_{\text{eff}}^{\ell }$ plays a key role not only in the global test of the standard model electroweak sector, but also in constraining the potential beyond standard model new physics at high energy frontier. CEPC proposes a two year running period around the Z boson mass pole at high instataneous luminosity, providing a large data sample with $4\times 10^{12}$ $Z$ candidates generated in total. It allows a high precision measurement of ${\sin }^2{\theta }_{\text{eff}}^{\ell }$ both in the lepton and quark final states, of which the uncertainty can be one order of magnitude lower than any previous measurement at the LEP, SLC, Tevatron and LHC. It will not only improve the overall precision of the ${\sin }^2{\theta }_{\text{eff}}^{\ell }$ experimental determination to be comparable to the preicision of the theoretical calculation with two-loop radiative corrections, but also provide direct comparisons between different final states. In this paper, we also study the measurement of ${\sin }^2{\theta }_{\text{eff}}^{\ell }$ at high mass region. With one month data taken, the precision of ${\sin }^2{\theta }_{\text{eff}}^{\ell }$ measured at 130 GeV from $b$ quark final state is 0.00010, which will be an important experimental observation on the energy-running effect of ${\sin }^2{\theta }_{\text{eff}}^{\ell }$.

    ↳ hep-exhep-phCPC(2023)·7 citations
31. 31*

    Results on photon-mediated dark matter-nucleus interactions from the PICO-60 C${}_3$F${}_8$ bubble chamber

    B. Ali🇨🇿 · I. J. Arnquist🇺🇸 · D. Baxter🇺🇸 · E. Behnke🇺🇸 · M. Bressler🇺🇸 · B. Broerman🇨🇦 · C. J. Chen🇺🇸 · K. Clark🇨🇦 · J. I. Collar🇺🇸 · P. S. Cooper🇺🇸 · C. Cripe🇺🇸 · M. Crisler🇺🇸 and 43 other authors

    Many compelling models predict dark matter coupling to the electromagnetic current through higher multipole interactions, while remaining electrically neutral. Different multipole couplings have been studied, among them anapole moment, electric and magnetic dipole moments, and millicharge. This study sets limits on the couplings for these photon-mediated interactions using non-relativistic contact operators in an effective field theory framework. Using data from the PICO-60 bubble chamber leading limits for dark matter masses between 2.7 GeV/c${}^2$ and 24 GeV/c${}^2$ are reported for the coupling of these photon-mediated dark matter-nucleus interactions. The detector was filled with 52 kg of C${}_3$F${}_8$ operating at thermodynamic thresholds of 2.45 keV and 3.29 keV, reaching exposures of 1404 kg-day and 1167 kg-day, respectively.

    ↳ astro-ph.COhep-exhep-phPRD(2022)·14 citations
32. 32*

    Energetics of quantum vacuum friction. II: Dipole fluctuations and field fluctuations

    Xin Guo🇨🇳 · Kimball A. Milton🇺🇸 · Gerard Kennedy🇬🇧 · William P. McNulty🇺🇸 · Nima Pourtolami🇨🇦 · Yang Li🇨🇳

    As a second paper in series with arXiv:2108.01539, we discuss here quantum vacuum friction on an intrinsically dissipative particle. The friction arises not only from the field fluctuations but also from the dipole fluctuations intrinsic to the particle. As a result, the dissipative particle can be out of the nonequilibrium steady state (NESS), where it loses or gains internal energy. Only if the temperature of the particle equals a special NESS temperature will the particle be in NESS. We first derive the NESS conditions which give the NESS temperature of the particle as a function of the radiation temperature and the velocity of the particle. Imposing the NESS conditions, we then obtain an expression for the quantum vacuum friction in NESS. The NESS quantum vacuum friction is shown to be always negative definite, therefore a true drag. The NESS temperature and quantum vacuum friction are calculated numerically for various models. Out of NESS, even though the quantum vacuum frictional force no longer has a definite sign in the rest frame of the radiation, we find the external force needed to keep the particle moving must be in the same direction as the motion of the particle. This then excludes the possibility of making a perpetual motion machine, which could convert the vacuum energy into useful mechanical work. In addition, we find that the deviation of the temperature of the particle from its NESS temperature causes the particle to lose or gain internal energy in such a way that the particle would return to NESS after deviating from it. This enables experimental measurements of the NESS temperature of the particle to serve as a feasible signature for these quantum vacuum frictional effects.

    ↳ hep-thcond-mat.mes-hallhep-phphysics.atom-ph+1PRD(2022)·10 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.