Tue·Mar 24, 2020Tuesday·March 24, 2020

1. 01*

   Strange Jet Tagging

   Yuichiro Nakai🇨🇳 · David Shih🇺🇸 · Scott Thomas🇺🇸

   Tagging jets of strongly interacting particles initiated by energetic strange quarks is one of the few largely unexplored Standard Model object classification problems remaining in high energy collider physics. In this paper we investigate the purest version of this classification problem in the form of distinguishing strange-quark jets from down-quark jets. Our strategy relies on the fact that a strange-quark jet contains on average a higher ratio of neutral kaon energy to neutral pion energy than does a down-quark jet. Long-lived neutral kaons deposit energy mainly in the hadronic calorimeter of a high energy detector, while neutral pions decay promptly to photons that deposit energy mainly in the electromagnetic calorimeter. In addition, short-lived neutral kaons that decay in flight to charged pion pairs can be identified as a secondary vertex in the inner tracking system. Using these handles we study different approaches to distinguishing strange-quark from down-quark jets, including single variable cut-based methods, a boosted decision tree (BDT) with a small number of simple variables, and a deep learning convolutional neural network (CNN) architecture with jet images. We show that modest gains are possible from the CNN compared with the BDT or a single variable. Starting from jet samples with only strange-quark and down-quark jets, the CNN algorithm can improve the strange to down ratio by a factor of roughly 2 for strange tagging efficiencies below 0.2, and by a factor of 2.5 for strange tagging efficiencies near 0.02.

   hep-phhep-ex39 citations
2. 02*

   Central exclusive ${\chi }_{c,b}$ production at high energy colliders and gluon saturation approach

   F. Kopp🇧🇷 · M.B. Gay Ducati🇧🇷 · M.V.T. Machado🇧🇷

   The central exclusive production of ${\chi }_c$ and ${\chi }_b$ at the LHC, RHIC and Tevatron energies is analyzed, using the recent unintegrated parton distribution (UGDs) functions available in the package TMDlib. Comparison with data is performed, which tests the underlying assumptions basing the theoretical approach and it can constrain the unintegrated gluon distribution function at the small-$x$ region. Predictions for LHC energies using recent UGDs based in CCFM formalism are provided. It is explored the underlying uncertainties on this production as the choice for the unintegrated gluon distribution and factorization scale is done. Moreover, based on the parton saturation model for the gluon distribution, analytical expressions for the rapidity distributions are proposed. The prompt production of $J/\psi +\gamma$ and ${\rm Y}+\gamma$ is computed for the first time for LHC energies within the very same formalism used for $\chi$ production.

   hep-phhep-exPLB(2020)·3 citations
3. 03*

   Sphaleron in the first-order electroweak phase transition with the dimension-six Higgs operator

   Vo Quoc Phong🇻🇳 · Phan Hong Khiem🇻🇳 · Ngo Phuc Duc Loc🇻🇳 · Hoang Ngoc Long🇻🇳

   By adding the dimension-six operator for the Higgs potential (denoted ${\mathcal{O}}_6$) in Standard Model, we have a first-order electroweak phase transition (EWPT) whose strength is larger than unity. The cutoff parameter of the dimension-six Higgs operator ($\Lambda$) is found to be in the range 593-860 GeV with the Wilson parameter equals to unity; it is also shown that the greater the $\Lambda$, the lower the phase transition strength and the larger the Wilson parameter, the wider the domain of $\Lambda$. At zero temperature, the sphaleron energy is calculated with a smooth ansatz and an ansatz with scale-free parameters, thereby we find that smooth profiles are not more accurate than profiles with scale-free parameters. Then, using the one-loop effective Higgs potential with the inclusion of ${\mathcal{O}}_6$ instead of all possible dimension-six operators, we directly calculate the electroweak sphaleron energy at finite temperature with the scale-free parameters ansatz and show that the decoupling condition is satisfied during the phase transition. Moreover, we can reevaluate the upper bound of the cutoff scale inferred from the first-order phase transition. In addition, with the upper bound of the cutoff parameter (about 800-860 GeV), EWPT is a solution to the energy scale of the dimension-six operators. There is an extended conclusion that EWPT can only be solved at a large energy scale than that of SM.

   hep-phPRD(2020)·20 citations
4. 04*

   Multiparton webs beyond three loops

   Neelima Agarwal · Abhinava Danish🇮🇳 · Lorenzo Magnea🇮🇹 · Sourav Pal🇮🇳 · Anurag Tripathi🇮🇳

   Correlators of Wilson-line operators are fundamental ingredients for the study of the infrared properties of non-abelian gauge theories. In perturbation theory, they are known to exponentiate, and their logarithm can be organised in terms of collections of Feynman diagrams called webs. We study the classification of webs to high perturbative orders, proposing a set of tools to generate them recursively: in particular, we introduce the concept of Cweb, or correlator web, which is a set of skeleton diagrams built with connected gluon correlators, instead of individual Feynman diagrams. As an application, we enumerate all Cwebs entering the soft anomalous dimension matrix for multi-parton scattering amplitudes at four loops, and we compute the mixing matrices for all Cwebs connecting four or five Wilson lines at that loop order, verifying that they obey sum rules that were derived or conjectured in the literature. Our results provide the colour building blocks for the calculation of the soft anomalous dimension matrix at four-loop order.

   hep-phhep-thJHEP(2020)·31 citations
5. 05*

   Axions in neutron star mergers

   Steven P. Harris🇺🇸 · Jean-Francois Fortin🇨🇦 · Kuver Sinha🇺🇸 · Mark G. Alford🇺🇸

   Supernovae and cooling neutron stars have long been used to constrain the properties of axions, such as their mass and interactions with nucleons and other Standard Model particles. We investigate the prospects of using neutron star mergers as a similar location where axions can be probed in the future. We examine the impact axions would have on mergers, considering both the possibility that they free-stream through the dense nuclear matter and the case where they are trapped. We calculate the mean free path of axions in merger conditions, and find that they would free-stream through the merger in all thermodynamic conditions. In contrast to previous calculations, we integrate over the entire phase space while using a relativistic treatment of the nucleons, assuming the matrix element is momentum-independent. In particular, we use a relativistic mean field theory to describe the nucleons, taking into account the precipitous decrease in the effective mass of the nucleons as density increases above nuclear saturation density. We find that within current constraints on the axion-neutron coupling, axions could cool nuclear matter on timescales relevant to neutron star mergers. Our results may be regarded as first steps aimed at understanding how axions affect merger simulations and potentially interface with observations.

   hep-phastro-ph.HEnucl-thJCAP(2020)·47 citations
6. 06*

   Electron and muon $(g-2)$ in the B-LSSM

   Jin-Lei Yang🇨🇳 · Tai-Fu Feng🇨🇳 · Hai-Bin Zhang🇨🇳

   The theoretical predictions in the standard model (SM) and measurements on the anomalous magnetic dipole moments (MDM) of muon and electron have great precision, hence the MDMs of muon and electron have close relation with the new physics (NP) beyond the SM. Recently, a negative $\sim 2.4\sigma$ discrepancy between the measured electron MDM and the SM prediction results from a recent improved determination of the fine structure constant. Combined with the long-lasting muon MDM discrepancy which is about $\sim 3.7\sigma$, it is difficult to explain both the magnitude and opposite signs of the deviations in a consistent model, without introducing large flavour-violating effects. The analysis shows that they can be explained in the minimal supersymmetric extension (MSSM) of the SM with local $B-L$ gauge symmetry (B-LSSM). Comparing with the MSSM, new parameters in the B-LSSM can affect the theoretical predictions on lepton MDMs, and the effects of them are explored.

   hep-phJ.Phys.G(2020)·48 citations
7. 07*

   Neutrino masses and mixing angles in a model with six Higgs triplets and $A_4$ symmetry

   Raghavendra Srikanth Hundi🇮🇳 · Itishree Sethi🇮🇳

   We have considered a model \cite{ma-weg}, where masses and a mixing pattern for neutrinos are governed by six Higgs triplets and $A_4$ symmetry. In this model we have applied a certain diagonalisation procedure through which we have shown that neutrino masses can have both normal or inverted hierarchy. We have also shown that current neutrino oscillation data can be explained in this model.

   hep-phPRD(2020)·5 citations
8. 08*

   Electroweak fermion triangle loop contributions to the muon anomalous magnetic moment revisited

   Ken Sasaki🇯🇵

   The contribution to the muon anomalous magnetic moment from the fermion triangle loop diagrams connected to the muon line by a photon and a $Z$ boson is reanalyzed in the unitary gauge. With use of the anomalous axial-vector Ward identity, it is shown that the calculation in the unitary gauge exactly coincides with the one in the 't Hooft-Feynman gauge. The part which arises from the ordinary axial-vector Ward identity corresponds to the contribution of the neutral Goldstone boson. For the top-quark contribution, the one-parameter integral form is obtained up to the order of $m_{\mu }^2/m_Z^2$. The results are compared with those obtained by the asymptotic expansion method.

   hep-phPTEP(2020)·0 citations
9. 09*

   String Breaking, Baryons, Medium, and Gauge/String Duality

   Oleg Andreev🇷🇺

   The string breaking phenomenon in QCD can be studied using the gauge/string duality. In this approach, one can make estimates of some of the string breaking distances at non-zero temperature and baryon chemical potential. These point towards the enhancement of baryon production in strong decays of heavy mesons in dense baryonic medium.

   hep-phhep-lathep-thnucl-thPRD(2020)·22 citations
10. 10*

    Hard diffractive ${\eta }_{\mathrm{c},\mathrm{b}}$ hadroproduction at the LHC

    Tichouk🇨🇳 · Hao Sun🇨🇳 · Xuan Luo🇨🇳

    In this paper, we investigate the inclusive diffractive hadroproduction for ${\eta }_{\mathrm{c}}$ and ${\eta }_{\mathrm{b}}$ at the LHC energies. Based on the NRQCD factorization formalism and the resolved-Pomeron model for the quarkonium production mechanism, we estimate the rapidity, momentum fraction loss dependence of the cross section. We give prediction ratios for single and central diffractive processes with respect to non diffractive process. These inclusive processes are sensitive to gluon content of Pomeron for small-$x$ and Reggeon for large-$x$, useful to study small and large-$x$ physics and good to test different mechanism for ${\eta }_{\mathrm{c}}$ and ${\eta }_{\mathrm{b}}$ production at the LHC. They also serve as the background to related exclusive processes thus should be predicted. Our results demonstrate that the Reggeon contribution of diffractive processes can be sizable, even sometimes dominant over Pomeron, and that its study can be useful to better constrain the Reggeon parton content. The experimental study of Reggeon can be carried out in certain kinematic windows.

    hep-phPRD(2020)·8 citations
11. 11*

    CP violating phase sum rule ${\delta }_{\mathrm{KM}}^q+{\delta }_{\mathrm{KM}}^l=0$ for CKM and PMNS matrices

    Junxing Pan🇨🇳 · Jin Sun🇨🇳 · Xiao-Dong Ma🇹🇼 · Xiao-Gang He🇹🇼

    The non-zero Dirac phases ${\delta }^q$ and ${\delta }^l$ in the CKM and PMNS mixing matrices signify CP violation. In general they are independent. Experimental data including recent T2K results show, however, that in the original KM parameterization for the mixing matrix, the sum ${\delta }_{\mathrm{KM}}^q+{\delta }_{\mathrm{KM}}^l$ is close to zero with ${\delta }_{\mathrm{KM}}^q$ to be approximately $\pi /2$. The KM parameterization may have provided some hints that these phases are actually related and CP is maximally violated. We show that this sum rule can be accommodated in models with spontaneous CP violation where both phases originate from a non-trivial common spontaneous CP violating maximized phase in the Higgs potential. We find some interesting phenomenological consequences for flavor changing neutral current and CP violation for such a model. In particular, data from $B_s-{\bar{B}}_s$ mixing provide very strong constraints on the mass scale for the new neutral scalars in the model, yet the model still allows the electric dipole moments of electron and neutron to reach to their current upper bounds. The model can be tested by near future experiments.

    hep-phPLB(2020)·6 citations
12. 12*

    Sensitivities to secret neutrino interaction at FASER$\nu$

    Majid Bahraminasr🇮🇷 · Pouya Bakhti🇮🇷 · Meshkat Rajaee🇮🇷

    We study the impact of the coupling of neutrinos with a new light neutral gauge boson, $Z^{\prime }$, with a mass of less than 500 {\rm MeV} in FASER$\nu$ experiment. Scenarios in which a light gauge boson is coupled to neutrinos are motivated within numerous contexts which are designed to explain various anomalies in particle physics and cosmology. This interaction leads to a new decay mode for charged mesons to a light lepton plus neutrino and $Z^{\prime }$, (${\pi }^{+}(K^{+})\to e^{+}\nu Z^{\prime }$) followed by the subsequent decay of $Z^{\prime }$ into the pair of neutrino and anti-neutrino, ($Z^{\prime }\to \nu \bar{\nu }$). FASER$\nu$, the Forward Search Experiment at the LHC, has the potential to detect collider neutrinos for the first time. In particular, the FASER$\nu$ emulsion detector will provide the opportunity to detect $\tau$-neutrinos and to measure their energies. Using this ability of FASER$\nu$ emulsion detector, we investigate the potential of FASER$\nu$ experiment and the proposed upgraded version of this experiment, FASER2$\nu$, to constrain the coupling of a neutrino with the light gauge boson.

    hep-phhep-exJ.Phys.G(2021)·26 citations
13. 13*

    CP asymmetry from hadronic charm rescattering in $B^{\pm }\to {\pi }^{-}{\pi }^{+}{\pi }^{\pm }$ decays at the high mass region

    I. Bediaga🇧🇷 · T. Frederico🇧🇷 · P. C. Magalhaes🇬🇧

    A model for the $B^{\pm }\to {\pi }^{-}{\pi }^{+}{\pi }^{\pm }$ decay amplitude is proposed to study the large CP violation observed at the high mass region of the Dalitz plane. A short distance $b\to u$ amplitude with the weak phase $\gamma$ is considered together with the contribution of a hadronic charm loop and a s-wave $D\bar{D}\to \pi \pi$ rescattering. In the model, the ${\chi }_c^0$ appears as a narrow resonant state of the $D\bar{D}$ system below threshold. It is introduced in an unitary two channel S-matrix model of the coupled $D\bar{D}$ and $\pi \pi$ channels, where the ${\chi }_c^0$ complex pole in $D\bar{D}$ channel shows its signature in the off-diagonal matrix element and in the associated $D\bar{D}\to \pi \pi$ transition amplitude. The strong phase of the resulting decay amplitude has a sharp sign change at the $D\bar{D}$ threshold, changing the sign of the CP asymmetry, as it is observed in the data. We conclude that the hadronic charm loop and rescattering mechanism are relevant to the broadening of the CP asymmetry around the ${\chi }_c^0$ resonance in the $\pi \pi$ channel. This novel mechanism provides a possible interpretation of the CP asymmetry defier experimental result presented by the LHCb collaboration for the $B^{\pm }\to {\pi }^{-}{\pi }^{+}{\pi }^{\pm }$ decay in the high mass region.

    hep-phhep-exPLB(2020)·14 citations
14. 14*

    The high-order nonrelativistic Hamiltonian of electromagnetic system

    Wanping Zhou🇨🇳 · Xuesong Mei🇨🇳 · Haoxue Qiao🇨🇳

    The nonrelativistic Hamiltonians of scalar, spinor and vector particles in the electromagnetic field are studied by applying the Douglas-Kroll-Hess approach. Their relativistic Hamiltonians are expanded on the potential, and the Hamiltonians containing one- and two-photon potentials are derived. The nonrelativistic Hamiltonians up to $m{\alpha }^8$ order are obtained by applying Taylor expansion on momentum, and the result of spin-1/2 spinor is coincided with the result obtained by applying scattering matching approach in the Ref.~[Phys. Rev. A {\bf 100}, 012513 (2019)]. Then, the singularities in Hamiltonian of Coulomb systems are separated out and cancelled. The regularized Hamiltonian up to $m{\alpha }^8$ order for scaler and electron in Coulomb field are obtained. The numerical results of relativistic corrections are coincided with the relativistic theory. The regularized Hamiltonian up to $m{\alpha }^6$ for multi-electrons in Coulomb field are also derived.

    hep-phphysics.atom-ph0 citations
15. 15*

    Average speed and its powers $v^n$ of a heavy quark in quarkonia

    Guo-Li Wang🇨🇳 · Tai-Fu Feng🇨🇳 · Xing-Gang Wu🇨🇳

    The typical velocity of a heavy quark in a quarkonium is a widely used quantity, in this paper, based on the relativistic Bethe-Salpeter equation method, we calculate the average values $\overline{|\mathbf{q}{|}^n}$ and $\overline{|\mathbf{v}{|}^n}\equiv v^n$ of a heavy quark in a $S$ wave or $P$ wave quarkonium rest frame, where $\mathbf{q}$ and $\mathbf{v}$ are the three dimensional momentum and velocity, $n=1,2,3,4$. For a charm quark in $J/\psi$, we obtained $v_{J/\psi }=0.46$, $v_{J/\psi }^2=0.26$, $v_{J/\psi }^3=0.18$, and $v_{J/\psi }^4=0.14$, for a bottom quark in ${\rm Y}(1S)$, $v_{{\rm Y}(1S)}=0.24$, $v_{{\rm Y}(1S)}^2=0.072$, $v_{{\rm Y}(1S)}^3=0.025$, and $v_{{\rm Y}(1S)}^4=0.010$. The values indicate that $v^n>v^{n_1}\cdot v^{n_2}$, where $n_1+n_2=n$, which is correct for all the charmonia and bottomonia. Our results also show the poor convergence if we make the {speed} expansion in charmonium system, but good for bottomonium. Based on the $v^n$ values and the following obtained relations $v_{4S}^n>v_{3S}^n>v_{2S}^n>v_{1S}^n$, $v_{4P}^n>v_{3P}^n>v_{2P}^n>v_{1P}^n$ and $v_{mP}^n>v_{mS}^n$ ($n,m=1,2,3,4$), we conclude that highly excited quarkonia have larger relativistic corrections than those of the corresponding low excited and ground states, and there are large relativistic corrections in charmonium system.

    hep-phhep-exPRD(2020)·15 citations
16. 16*

    Radiative $p_{\perp }$-broadening of fast partons in an expanding quark-gluon plasma

    B.G. Zakharov🇷🇺

    We study contribution of radiative processes to $p_{\perp }$-broadening of fast partons in an expanding quark-gluon plasma. It is shown that the radiative correction to $⟨p_{\perp }^2⟩$ for the QGP produced in $AA$-collisions at RHIC and LHC may be negative, and comparable in absolute value with the non-radiative contribution. We have found that the QGP expansion enhances the radiative suppression of $p_{\perp }$-broadening as compared to the static medium.

    hep-phnucl-thEPJC(2021)·11 citations
17. 17*

    Geometric optics in the presence of axion-like particles in curved space-time

    Dominik J. Schwarz🇩🇪 · Jishnu Goswami🇩🇪 · Aritra Basu🇩🇪

    We present a concise derivation of geometric optics in the presence of axionic fields in a curved space-time. Whenever light can be described via geometric optics (the eikonal approximation), the only difference to the situation without axionic field is the phenomenon of achromatic birefringence. Consequently, redshift of light and distance estimates based on propagating light rays, as well as shear and magnification due to gravitational lensing are not affected by the interaction of light with an axionic field.

    hep-phastro-ph.IMgr-qcPRD(2021)·18 citations
18. 18*

    Phase transitions in perturbative walking dynamics

    Aleksandr Azatov🇮🇹 · Miguel Vanvlasselaer🇮🇹

    In this paper, we investigate the dynamics of the confinement-deconfinement phase transition in a toy model where the walking dynamics is realized perturbatively. We study the properties of the phase transition focusing on the possible cosmological signatures it can provide. Interestingly the model is well under perturbative control only when the mass of the lightest field - the dilaton/scalon is much lighter than the rest of the fields and the phase transition proceeds slowly leading to strong signals in the stochastic gravitational wave spectrum.

    hep-phhep-thJHEP(2020)·42 citations
19. 19*

    Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center

    Kevork N. Abazajian🇺🇸 · Shunsaku Horiuchi🇺🇸 · Manoj Kaplinghat🇺🇸 · Ryan E. Keeley🇺🇸 · Oscar Macias🇯🇵

    The extended excess toward the Galactic Center (GC) in gamma rays inferred from Fermi-LAT observations has been interpreted as being due to dark matter (DM) annihilation. Here, we perform new likelihood analyses of the GC and show that, when including templates for the stellar galactic and nuclear bulges, the GC shows no significant detection of a DM annihilation template, even after generous variations in the Galactic diffuse emission models and a wide range of DM halo profiles. We include Galactic diffuse emission models with combinations of three-dimensional inverse Compton maps, variations of interstellar gas maps, and a central source of electrons. For the DM profile, we include both spherical and ellipsoidal DM morphologies and a range of radial profiles from steep cusps to kiloparsec-sized cores, motivated in part by hydrodynamical simulations. Our derived upper limits on the dark matter annihilation flux place strong constraints on DM properties. In the case of the pure $b$-quark annihilation channel, our limits on the annihilation cross section are more stringent than those from the Milky Way dwarfs up to DM masses of approximately TeV and rule out the thermal relic cross section up to approximately 300 GeV. Better understanding of the DM profile, as well as the Fermi-LAT data at its highest energies, would further improve the sensitivity to DM properties.

    hep-phastro-ph.COastro-ph.HEPRD(2020)·105 citations
20. 20*

    Centrality dependence of chemical freeze-out parameters and strangeness equilibration in RHIC and LHC energies

    Deeptak Biswas🇮🇳

    We have estimated centrality variation of chemical freeze-out parameters from yield data at mid-rapidity of ${\pi }^{\pm }$, $K^{\pm }$ and $p$, $\bar{p}$ for collision energies of RHIC (Relativistic Heavy Ion Collider), Beam Energy Scan (RHIC-BES) program, and LHC (Large Hadron Collider). We have considered a simple hadron resonance gas model and employed a formalism involving conserved charges ($B,Q,S$) of QCD for parameterization. Along with temperature and three chemical potentials ($T,{\mu }_B,{\mu }_Q,{\mu }_S$), a strangeness under-saturation factor (${\gamma }_S$) has been used to incorporate the partial equilibration in the strange sector. Our obtained freeze-out temperature does not vary much with centrality, whereas chemical potentials and ${\gamma }_S$ seem to have a significant dependence. The strange hadrons are found to deviate from a complete chemical equilibrium at freeze-out at the peripheral collisions. This deviation appears to be more prominent as the collision energy decreases at lower RHIC-BES energies. We have also shown that this departure from equilibrium reduces towards central collisions, and strange particle equilibration may happen after a threshold number of participants in $A$-$A$ collision.

    hep-phnucl-thAdv.High Energy Phys.(2021)·24 citations
21. 21*

    Baryons from Mesons: A Machine Learning Perspective

    Yarin Gal🇬🇧 · Vishnu Jejjala🇿🇦 · Damian Kaloni Mayorga Pena🇿🇦 · Challenger Mishra🇬🇧

    Quantum chromodynamics (QCD) is the theory of the strong interaction. The fundamental particles of QCD, quarks and gluons, carry colour charge and form colourless bound states at low energies. The hadronic bound states of primary interest to us are the mesons and the baryons. From knowledge of the meson spectrum, we use neural networks and Gaussian processes to predict the masses of baryons with 90.3% and 96.6% accuracy, respectively. These results compare favourably to the constituent quark model. We as well predict the masses of pentaquarks and other exotic hadrons.

    hep-phcs.LGhep-lathep-th+1Int.J.Mod.Phys.A(2022)·19 citations
22. 22*

    A Fundamental QCD Axion Model

    Alberto Salvio🇮🇹

    We construct and study a fundamental field theory of the QCD axion: all couplings flow to zero in the infinite-energy limit realizing the totally asymptotically free (TAF) scenario. Some observable quantities (such as the masses of new quarks and scalars) are predicted at low energies by the TAF requirement in terms of gauge couplings and a vector-boson mass. Here the minimal model of this sort is explored; the axion sector is charged under an SU(2) gauge group and a dark photon appears at low energies. This model can be TAF and feature an absolutely stable vacuum at the same time.

    hep-phhep-thPLB(2020)·11 citations
23. 23*

    Beyond the Standard Model Effective Field Theory: The Singlet Extended Standard Model

    Shekhar Adhikari🇺🇸 · Ian M. Lewis🇺🇸 · Matthew Sullivan🇺🇸

    One of the assumptions of simplified models is that there are a few new particles and interactions accessible at the LHC and all other new particles are heavy and decoupled. The effective field theory (EFT) method provides a consistent method to test this assumption. Simplified models can be augmented with higher order operators involving the new particles accessible at the LHC. Any UV completion of the simplified model will be able to match onto these beyond the Standard Model EFTs (BSM-EFT). In this paper we study the simplest simplified model: the Standard Model extended by a real gauge singlet scalar. In addition to the usual renormalizable interactions, we include dimension-5 interactions of the singlet scalar with Standard Model particles. As we will show, even when the cutoff scale is 3 TeV, these new effective interactions can drastically change the interpretation of Higgs precision measurements and scalar searches. In addition, we discuss how power counting in a BSM-EFT depends strongly on the processes and parameter space under consideration. Finally, we propose a ${\chi }^2$ method to consistently combine the limits from new particle searches with measurements of the Standard Model. Unlike imposing a hard cut off on heavy resonance rates, our method allows fluctuations in individual channels that are consistent with global fits.

    hep-phPRD(2021)·33 citations
24. 24*

    Tensor form factors of $P\to P,S,V$ and $A$ transitions within the standard and the covariant light-front approaches

    Qin Chang🇨🇳 · Xiao-Lin Wang🇨🇳 · Li-Ting Wang🇨🇳

    In this paper, we investigate the tensor form factors of $P\to P,S,V$ and $A$ transitions within the standard light-front (SLF) and the covariant light-front (CLF) quark models (QMs). The self-consistency and Lorentz covariance of CLF QM are analyzed via these quantities, and the effects of zero-mode are discussed. For the $P\to V$ and $A$ transitions, besides the inconsistence between the results extracted via longitudinal and transverse polarization states, which is caused by the residual $\omega$-dependent spurious contributions, we find and analyze a "new" self-consistence problem of the traditional CLF QM, which is caused by the different strategies for dealing deal with the trace term in CLF matrix element. A possible solution to the problems of traditional CLF QM is discussed and confirmed numerically. Finally, the theoretical predictions for the tensor form factors of some $c\to q,s$ and $b\to q,s,c$ ($q=u,d$) induced $P\to P,S,V$ and $A$ transitions are updated within the CLF QM with a self-consistent scheme.

    hep-phhep-exCPC(2020)·22 citations
25. 25*

    Four-jet production via double parton scattering in $pA$ collisions at the LHC

    B. Blok (Technion)🇮🇱 · F.A. Ceccopieri (Technion)🇮🇱

    We present predictions for the double parton scattering (DPS) four-jet production cross sections in $pA$ collisions at the LHC. Relying on the experimental capabilities to correlate centrality with impact parameter $B$ of the proton-nucleus collision, we discuss a strategy to extract the double parton scattering contributions in $pA$ collisions, which gives direct access to double parton distribution in the nucleon. We show that the production cross sections via DPS of four jets, out of which two may be light- or heavy-quark jets, are large enough to allow the method to be used already with data accumulated in 2016 $pA$ run.

    hep-phhep-exnucl-exnucl-thPRD(2020)·2 citations
26. 26*

    Prospective constraints on anomalous Higgs boson interactions in an effective Lagrangian via diphoton production at FCC-hh

    H. Denizli🇹🇷 · A. Senol🇹🇷

    We study the CP-conserving and CP-violating dimension-six operators of Higgs-gauge boson couplings via $pp\to \gamma \gamma$+n-jet signal process in a strongly interacting light Higgs based effective field theory framework at the center of mass energy of 100 TeV. In order to perform a simulation which includes realistic detector effects, the signal events in the existence of ${\bar{c}}_{\gamma }$, ${\tilde{c}}_{\gamma }$, ${\bar{c}}_g$ and ${\tilde{c}}_g$ Wilson coefficients and the relevant SM background events are generated in MadGraph, then passed through Pythia 8 for parton showering and finally run Delphes with FCC-hh detector card. In our analysis, we focus on the kinematic variables of the two photons in the final states of signal and relevant background processes that can reconstruct Higgs boson. We obtain constraints on the four Wilson coefficients of dimension-six operators using the transverse momentum distribution of reconstructed di-photon system with optimized kinematic cuts. The obtained 95\% confidence level limits on these four Wilson coefficients including detector effects at $\sqrt{s}$=100 TeV with an integrated luminosity of 30 ab${}^{-1}$ without systematic error are at least one order or more better than current experimental limits reported by ATLAS experiment. Even with ${\delta }_{sys}=2\%$ systematic error, we find comparable limits with current experimental results.

    hep-phNPB(2021)·2 citations
27. 27*

    Implications of light charged Higgs boson at the LHC Run III in the 2HDM

    Abdesslam Arhrib🇲🇦 · Rachid Benbrik🇲🇦 · Hicham Harouiz🇲🇦 · Stefano Moretti🇬🇧 · Yan Wang🇨🇳 · Qi-Shu Yan🇨🇳

    In this study, we focus on the bosonic decays of light charged Higgs boson (i.e., with $M_{H^{\pm }}<m_t$) in the 2-Higgs Doublet Model (2HDM) Type-I. To study the signal of such a charged Higgs state at the Large Hadron Collider (LHC), in a scenario where the $H^0$ boson is the Standard Model (SM)-like one already discovered, we assume that it decays mainly via $h^0{W}^{\pm \ast }$ and/or $H^{\pm }\to A^0{W}^{\pm \ast }$ (i.e., via an off-shell $W^{\pm }$ boson), which can reach a sizable Branching Ratio (BR) for $\tan \beta \ge 4$, when the exclusion bounds from $H^{\pm }\to \tau \nu$ and $cs$ searches get weaker. By using six Benchmark Points (BPs), which are consistent with current LHC constraints, we perform a Monte Carlo (MC) study and examine the sensitivity of the LHC to light charged Higgs boson decaying via the above bosonic modes and produced in top decay following both single top and top pair production processes. Our findings demonstrate that, when the integrated luminosity can reach 100 fb${}^{-1}$, the LHC has the potential to either discover or rule out most of these BPs via either of these two production and decay channels or both.

    hep-phhep-exPRD(2020)·22 citations
28. 28*

    Intensity Mapping as a Probe of Axion Dark Matter

    Jurek B. Bauer (U Göttingen)🇩🇪 · David J. E. Marsh (U Göttingen)🇩🇪 · Renée Hložek (U Toronto)🇨🇦 · Hamsa Padmanabhan (U Geneva/CITA)🇨🇦 · Alex Laguë (U Toronto/CITA)🇨🇦

    Intensity mapping (IM) of spectral lines has the potential to revolutionize cosmology by increasing the total number of observed modes by several orders of magnitude compared to the cosmic microwave background (CMB) anisotropies. In this paper, we consider IM of neutral hydrogen (HI) in the redshift range $0\lesssim z\lesssim 3$ employing a halo model approach where HI is assumed to follow the distribution of dark matter (DM) halos. If a portion of the DM is composed of ultralight axions then the abundance of halos is changed compared to cold dark matter below the axion Jeans mass. With fixed total HI density, ${\Omega }_{\mathrm{HI}}$, assumed to reside entirely in halos, this effect introduces a scale-independent increase in the HI power spectrum on scales above the axion Jeans scale, which our model predicts consistent with N-body simulations. Lighter axions introduce a scale-dependent feature even on linear scales due to its suppression of the matter power spectrum near the Jeans scale. We use the Fisher matrix formalism to forecast the ability of future HI surveys to constrain the axion fraction of DM and marginalize over astrophysical and model uncertainties. We find that a HIRAX-like survey is a very reliable IM survey configuration, being affected minimally by uncertainties due to non-linear scales, while the SKA1MID configuration is the most constraining as it is sensitive to non-linear scales. Including non-linear scales and combining a SKA1MID-like IM survey with the Simons Observatory CMB, the benchmark "fuzzy DM" model with $m_a=10^{-22}\text{ eV}$ can be constrained at the 10% level. For lighter ULAs this limit improves below 1%, and allows the possibility to test the connection between axion models and the grand unification scale across a wide range of masses.

    ↳ astro-ph.COastro-ph.GAhep-phMNRAS(2020)·73 citations
29. 29*

    Constructive Gravity: Foundations and Applications

    Frederic P. Schuller🇳🇱

    Constructive gravity allows to calculate the Lagrangian for gravity, provided one previously prescribes the Lagrangian for all matter fields on a spacetime geometry of choice. We explain the physical and mathematical foundation of this result and point out how to answer questions about gravity that could not be meaningfully asked previously.

    ↳ gr-qchep-ph5 citations
30. 30*

    First-principles calculation of electroweak box diagrams from lattice QCD

    Xu Feng🇨🇳 · Mikhail Gorchtein🇩🇪 · Lu-Chang Jin🇺🇸 · Peng-Xiang Ma🇨🇳 · Chien-Yeah Seng🇩🇪

    We present the first realistic lattice QCD calculation of the $\gamma W$-box diagrams relevant for beta decays. The nonperturbative low-momentum integral of the $\gamma W$ loop is calculated using a lattice QCD simulation, complemented by the perturbative QCD result at high momenta. Using the pion semileptonic decay as an example, we demonstrate the feasibility of the method. By using domain wall fermions at the physical pion mass with multiple lattice spacings and volumes, we obtain the axial $\gamma W$-box correction to the semileptonic pion decay, ${\square }_{\gamma W}^{VA}{|}_{\pi }=2.830(11{)}_{\mathrm{stat}}(26{)}_{\mathrm{sys}}\times 10^{-3}$, with the total uncertainty controlled at the level of $\sim 1$\%. This study sheds light on the first-principles computation of the $\gamma W$-box correction to the neutron decay, which plays a decisive role in the determination of $|V_{ud}|$.

    ↳ hep-lathep-exhep-phPRL(2020)·99 citations
31. 31*

    Quark polarization from parton scatterings in heavy ion collisions

    Jun-Jie Zhang🇨🇳 · Ren-Hong Fang🇨🇳 · Qun Wang🇨🇳 · Xin-Nian Wang🇨🇳

    Based on the result in our previous work, we calculate the polarization of quarks from parton scatterings in high energy heavy ion collisions. The result is compared with the STAR data at $\sqrt{s_{NN}}=200$ GeV.

    ↳ nucl-thhep-phNPA(2021)·0 citations
32. 32*

    Behavior of a Free Quantum Particle in the Poincaré Upper Half-Plane Geometry

    Parham Dehghani🇹🇷 · S. Habib Mazharimousavi🇹🇷 · S. Danial Forghani🇹🇷

    Inspired by the recent work of Filho et al., a Hermitian momentum operator is introduced in a general curved space with diagonal metric. The modified Hamiltonian associated with this new momentum is calculated and discussed. Furthermore, granting the validity of the Heisenberg equation in a curved space, the Ehrenfest theorem is generalized and interpreted with the new position-dependent differential operator in a curved space. The modified Hamiltonian leads to a modified time-independent Schrödinger equation, which is solved explicitly for a free particle in the Poincaré upper half-plane geometry. It is shown that a "free particle" does not behave as it is totally free due to curved background geometry.

    ↳ hep-thhep-phAnnals Phys.(2020)·1 citation
33. 33*

    The observation of vibrating pear shapes in radon nuclei: update

    P.A. Butler🇬🇧 · L.P. Gaffney🇨🇭 · P. Spagnoletti🇬🇧 · J. Konki🇨🇭 · M. Scheck🇬🇧 · J.F. Smith🇬🇧 · K. Abrahams🇿🇦 · M. Bowry🇨🇦 · J. Cederkäll🇸🇪 · T. Chupp🇺🇸 · G. De Angelis🇮🇹 · H. De Witte🇧🇪 and 32 other authors

    There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the standard model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we have observed the low-lying quantum states in ${}^{224}$Rn and ${}^{226}$Rn by accelerating beams of these radioactive nuclei. We report here additional states not assigned in our 2019 publication. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.

    ↳ nucl-exhep-phnucl-thphysics.atom-phNature Commun.(2019)·50 citations
34. 34*

    On the axial-vector form factor of the nucleon and chiral symmetry

    Matthias F.M. Lutz🇩🇪 · Ulrich Sauerwein🇩🇪 · Rob G.E. Timmermans🇳🇱

    We consider the chiral Lagrangian with nucleon, isobar, and pion degrees of freedom. The baryon masses and the axial-vector form factor of the nucleon are derived at the one-loop level. We explore the impact of using on-shell baryon masses in the loop expressions. As compared to results from conventional chiral perturbation theory we find significant differences. An application to QCD lattice data is presented. We perform a global fit to the available lattice data sets for the baryon masses and the nucleon axial-vector form factor, and determine the low-energy constants relevant at N${}^3$LO for the baryon masses and at N${}^2$LO for the form factor. Partial finite-volume effects are considered. We point out that the use of on-shell masses in the loops results in non-analytic behavior of the baryon masses and the form factor as function of the pion mass, which becomes prominent for larger lattice volumes than presently used.

    ↳ hep-lathep-phEPJC(2020)·25 citations
35. 35*

    Mass spectra in $\mathcal{N}=1$ SQCD with additional colorless fields and problems with Seiberg's duality

    Victor L. Chernyak🇷🇺

    Considered is the direct $\mathcal{N}=1$ SQCD-like $\Phi$-theory with $SU(N_c)$ colors and $3N_c/2<N_F<2N_c$ flavors of light quarks $\overline{Q},Q$. Besides, it includes $N_F^2$ additional colorless but flavored fields ${\Phi }_i^j$ with the large mass parameter ${\mu }_{\Phi }\gg {\Lambda }_Q$, interacting with quarks through the Yukawa coupling. In parallel, is considered its Seiberg's dual variant, i.e. the $d\Phi$-theory with $(N_F-N_c)$ dual colors, $N_F$ flavors of dual quarks $\overline{q},q$ and $N_F^2$ elementary mion fields $M_j^i\to ({\overline{Q}}_j{Q}^i)$. In considered here vacua, the quarks of both theories are in the conformal regimes at scales $\mu <{\Lambda }_Q$. The mass spectra are calculated in sections 4 and 5. It is shown that they are different in the direct and dual theories, in disagreement with the Seiberg hypothesis about equivalence of two such theories. Besides it is shown in the direct theory that a qualitatively new phenomenon takes place: the seemingly heavy fields $\Phi$ `return back' and there appear two additional generations of light $\Phi$-particles with small masses ${\mu }_{2,3}^{\mathrm{pole}}(\Phi )\ll {\Lambda }_Q$. In Conclusions also presented comparison of mass spectra of these two theories for such values of parameters when the direct theory is in the very strong coupling regime, while the dual one is in the weak coupling IR-free logarithmic regime. It is shown that mass spectra of these two theories are parametrically different in this case.

    ↳ hep-thhep-ph5 citations
36. 36*

    Violation of slow-roll in non-minimal inflation

    Tomo Takahashi🇯🇵 · Tommi Tenkanen🇺🇸 · Shuichiro Yokoyama🇯🇵

    We show that a non-minimal coupling to gravity can not only make some inflationary models consistent with cosmological data, similar to the case of Higgs inflation, but can also invoke slow-roll violation to realize graceful exit from inflation. In particular, this is the case in models where a destabilizing mechanism that ends inflation should be assumed when the model is minimally coupled to gravity. As explicit examples, we consider the power-law and inverse monomial inflation models with a non-minimal coupling to gravity. While these models are excluded in the minimally coupled case, we show that they can become viable again in non-minimally coupled scenarios. In most scenarios we considered, reheating can be naturally realized via gravitational particle production but that this depends on the underlying theory of gravity in a non-trivial way.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2020)·18 citations
37. 37*

    Second-order Post-Minkowskian scattering in arbitrary dimensions

    Andrea Cristofoli🇩🇰 · Poul H. Damgaard🇩🇰 · Paolo Di Vecchia🇩🇰 · Carlo Heissenberg🇸🇪

    We extract the long-range gravitational potential between two scalar particles with arbitrary masses from the two-to-two elastic scattering amplitude at 2nd Post-Minkowskian order in arbitrary dimensions. In contrast to the four-dimensional case, in higher dimensions the classical potential receives contributions from box topologies. Moreover, the kinematical relation between momentum and position on the classical trajectory contains a new term which is quadratic in the tree-level amplitude. A precise interplay between this new relation and the formula for the scattering angle ensures that the latter is still linear in the classical part of the scattering amplitude, to this order, matching an earlier calculation in the eikonal approach. We point out that both the eikonal exponentiation and the reality of the potential to 2nd post-Minkowskian order can be seen as a consequence of unitarity. We finally present closed-form expressions for the scattering angle given by leading-order gravitational potentials for dimensions ranging from four to ten.

    ↳ hep-thgr-qchep-phJHEP(2020)·154 citations
38. 38*

    Dissecting the $\Delta I=1/2$ rule at large $N_c$

    Andrea Donini🇪🇸 · Pilar Hernández🇪🇸 · Carlos Pena🇪🇸 · Fernando Romero-López🇪🇸

    We study the scaling of kaon decay amplitudes with the number of colours, $N_c$, in a theory with four degenerate flavours, $N_f=4$. In this scenario, two current-current operators, $Q^{\pm }$, mediate $\Delta S=1$ transitions, such as the two isospin amplitudes of non-leptonic kaon decays for $K\to (\pi \pi {)}_{I=0,2}$, $A_0$ and $A_2$. In particular, we concentrate on the simpler $K\to \pi$ amplitudes, $A^{\pm }$, mediated by these two operators. A diagrammatic analysis of the large-$N_c$ scaling of these observables is presented, which demonstrates the anticorrelation of the leading $\mathcal{O}(1/N_c)$ and $\mathcal{O}(N_f/N_c^2)$ corrections in both amplitudes. Using our new $N_f=4$ and previous quenched data, we confirm this expectation and show that these corrections are $naturally$ large and may be at the origin of the $\Delta I=1/2$ rule. The evidence for the latter is indirect, based on the matching of the amplitudes to their prediction in Chiral Perturbation Theory, from which the LO low-energy couplings of the chiral weak Hamiltonian, $g^{\pm }$, can be determined. A NLO estimate of the $K\to (\pi \pi {)}_{I=0,2}$ isospin amplitudes can then be derived, which is in good agreement with the experimental value.

    ↳ hep-lathep-phEPJC(2020)·21 citations
39. 39*

    Varying Newton constant and black hole to white hole quantum tunneling

    G.E. Volovik🇫🇮

    The thermodynamics of black holes is discussed for the case, when the Newton constant $G$ is not a constant, but is the thermodynamic variable. This gives for the first law of the Schwarzschild black hole thermodynamics: $d{S}_{\text{BH}}=-AdK+\frac{dM}{T_{\text{BH}}}$, where the gravitational coupling $K=1/4G$, $M$ is the black hole mass, $A$ is the area of horizon, and $T_{\text{BH}}$ is Hawking temperature. From this first law it follows that the dimensionless quantity $M^2/K$ is the adiabatic invariant, which in principle can be quantized if to follow the Bekenstein conjecture. From the Euclidean action for the black hole it follows that $K$ and $A$ serve as dynamically conjugate variables. This allows us to calculate the quantum tunneling from the black hole to the white hole, and determine the temperature and entropy of the white hole.

    ↳ gr-qccond-mat.otherhep-phUniverse(2020)·15 citations
40. 40*

    Gravitational Wave Production right after a Primordial Black Hole Evaporation

    Keisuke Inomata🇯🇵 · Masahiro Kawasaki🇯🇵 · Kyohei Mukaida🇩🇪 · Takahiro Terada🇰🇷 · Tsutomu T. Yanagida🇨🇳

    We discuss the footprint of evaporation of primordial black holes (PBHs) on stochastic gravitational waves (GWs) induced by scalar perturbations. We consider the case where PBHs once dominated the Universe but eventually evaporated before the big bang nucleosynthesis. The reheating through the PBH evaporation could end with a sudden change in the equation of state of the Universe compared to the conventional reheating caused by particle decay. We show that this "sudden reheating" by the PBH evaporation enhances the induced GWs, whose amount depends on the length of the PBH-dominated era and the width of the PBH mass function. We explore the possibility to constrain the primordial abundance of the evaporating PBHs by observing the induced GWs. We find that the abundance parameter $\beta \gtrsim 10^{-5}\text{ - }10^{-8}$ for $\mathcal{O}(10^3\text{ - }10^5)\text{g}$ PBHs can be constrained by future GW observations if the width of the mass function is smaller than about a hundredth of the mass.

    ↳ astro-ph.COgr-qchep-phPRD(2020)·210 citations
41. 41*

    Effective photon mass and (dark) photon conversion in the inhomogeneous Universe

    Andres Aramburo Garcia🇳🇱 · Kyrylo Bondarenko🇨🇭 · Sylvia Ploeckinger🇳🇱 · Josef Pradler🇦🇹 · Anastasia Sokolenko🇦🇹

    Photons traveling cosmological distances through the inhomogeneous Universe experience a great variation in their in-medium induced effective mass. Using the EAGLE suite of hydrodynamical simulations, we infer the free electron distribution and thereby the effective photon mass after reionization. We use this data to study the inter-conversion of kinetically mixed photons and dark photons, which may occur at a great number of resonance redshifts, and obtain the "optical depth" against conversion along random lines-of-sight. Using COBE/FIRAS, Planck, and SPT measurements, we constrain the dark photon parameter space from the depletion of CMB photons into dark photons that causes both spectral distortions and additional anisotropies in the CMB. Finally, we also consider the conversion of sub-eV dark radiation into ordinary photons. We make the line-of-sight distributions of both, free electrons and dark matter, publicly available.

    ↳ astro-ph.COhep-phJCAP(2020)·53 citations
42. 42*

    Equivalence of Light-Front and Covariant Quantum Electrodynamics at One Loop Level and the form of the Gauge Boson Propagator

    Deepesh Bhamre🇮🇳 · Anuradha Misra🇮🇳

    We consider the three fundamental one loop Feynman diagrams of QED viz. vertex correction, fermion self-energy and vacuum polarization in the light-front gauge and discuss the equivalence of their standard covariant expressions with the light-front expressions obtained using light-cone time-ordered Hamiltonian perturbation theory. Although this issue has been considered by us and others previously, our emphasis in this article is on addressing the ambiguity regarding the correct form of the gauge boson propagator to be used in the light-front gauge. We generalize our earlier results and show, using an alternative method called the Asymptotic Method, how integrating over the light-front energy consistently in the covariant expression of each of the three one loop corrections leads to the propagating as well as the instantaneous diagrams of the light-front theory. In doing so, we re-establish the necessity of using the correct form of gauge boson propagator.

    ↳ hep-thhep-phPramana(2022)·5 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.