Fri·Feb 5, 2021Friday·February 5, 2021

1. 01*

   Discovery and exclusion prospects for staus produced by heavy Higgs bosons decays at the LHC

   Ernesto Arganda🇪🇸 · Víctor Martín-Lozano🇩🇪 · Anibal D. Medina🇦🇷 · Nicolás I. Mileo🇦🇷

   In a previous work we developed a search strategy for staus produced by the decay of the heavy CP-even Higgs boson $H$ within the context of the large $\tan \beta$ regime of the minimal supersymmetric standard model (MSSM) in an scenario of large stau mixing. Here we study the performance of such search strategy by confronting it with the complementary mixing pattern in which decays of both the CP-even and CP-odd heavy Higgs bosons contribute to the production of ${\tilde{\tau }}_1{\tilde{\tau }}_2^{\ast }+c.c$ pairs. Again, we focus on final states with two opposite-sign tau leptons and large missing transverse energy. We find that our proposed search strategy, although optimized for the large stau mixing scenario, is still quite sensitive to the complementary mixing pattern. For instance, with a total integrated luminosity of only 100 fb${}^{-1}$ we are able to exclude heavy Higgs masses above 850 GeV for average stau masses higher than 290 GeV. We also extend the results reported in the preceding work for the large mixing scenario by including now the exclusion limits at 100 fb${}^{-1}$ and the prospects both for exclusion and discovery in a potential high luminosity phase of the LHC (1000 fb${}^{-1}$). Finally, we discuss the possibility to distinguish the two mixing scenarios when they share the same relevant mass spectrum and both reach the discovery level with our search strategy.

   hep-phhep-exAdv.High Energy Phys.(2022)·6 citations
2. 02*

   Decoupling of Asymmetric Dark Matter During an Early Matter Dominated Era

   Prolay Chanda🇺🇸 · James Unwin🇺🇸

   In models of Asymmetric Dark Matter (ADM) the relic density is set by a particle asymmetry in an analogous manner to the baryons. Here we explore the scenario in which ADM decouples from the Standard Model thermal bath during an early period of matter domination. We first present a model independent analysis for a generic ADM candidate with s-wave annihilation cross section with fairly general assumptions regarding the origin of the early matter dominated period. We contrast our results to those from conventional ADM models which assume radiation domination during decoupling. Subsequently, we examine an explicit example of this scenario in the context of an elegant SO(10) implementation of ADM in which the matter dominated era is due to a long lived heavy right-handed neutrino. In the concluding remarks we discuss the prospects for superheavy ADM in this setting.

   hep-phJCAP(2021)·9 citations
3. 03*

   Dark Matter Freeze-out via Catalyzed Annihilation

   Chuan-Yang Xing🇨🇳 · Shou-Hua Zhu🇨🇳

   We present a new paradigm of dark matter freeze-out, where the annihilation of dark matter particles is catalyzed. We discuss in detail the regime that the depletion of dark matter proceeds via $2\chi \to 2A^{\prime }$ and $3A^{\prime }\to 2\chi$ processes, in which $\chi$ and $A^{\prime }$ denote dark matter and the catalyst respectively. In this regime, the dark matter number density is depleted polynomially rather than exponentially (Boltzmann suppression) as in classic WIMPs and SIMPs. The paradigm applies for a secluded weakly interacting dark sector with a dark matter in the $\text{MeV-TeV}$ mass range. The catalyzed annihilation paradigm is compatible with CMB and BBN constraints, with enhanced indirect detection signals.

   hep-phPRL(2021)·15 citations
4. 04*

   Two-loop QCD corrections to $Wb\bar{b}$ production at hadron colliders

   Simon Badger🇮🇹 · Heribertus Bayu Hartanto🇬🇧 · Simone Zoia🇮🇹

   We present an analytic computation of the two-loop QCD corrections to $u\bar{d}\to W^{+}b\bar{b}$ for an on-shell $W$-boson using the leading colour and massless bottom quark approximations. We perform an integration-by-parts reduction of the unpolarised squared matrix element using finite field reconstruction techniques and identify an independent basis of special functions that allows an analytic subtraction of the infrared and ultraviolet poles. This basis is valid for all planar topologies for five-particle scattering with an off-shell leg.

   hep-phhep-thPRL(2021)·109 citations
5. 05*

   The impact of $a_0^0(980)-f_0(980)$ mixing on the localized $CP$ violations of the $B^{-}\to K^{-}{\pi }^{+}{\pi }^{-}$ decay

   Jing-Juan Qi🇨🇳 · Zhen-Yang Wang🇨🇳 · Chao Wang🇨🇳 · Zhen-Hua Zhang🇨🇳 · Xin-Heng Guo🇨🇳

   In the framework of the QCD factorization approach, we study the localized $CP$ violations of the $B^{-}\to K^{-}{\pi }^{+}{\pi }^{-}$ decay with and without $a_0^0(980)-f_0(980)$ mixing mechanism, respectively, and find that the localized $CP$ violation can be enhanced by this mixing effect when the mass of the ${\pi }^{+}{\pi }^{-}$ pair is in the vicinity of the $f_0(980)$ resonance. The corresponding theoretical prediction results are ${\mathcal{A}}_{CP}(B^{-}\to K{f}_0\to K^{-}{\pi }^{+}{\pi }^{-})=[0.24,0.36]$ and ${\mathcal{A}}_{CP}(B^{-}\to K^{-}{f}_0(a_0)\to K^{-}{\pi }^{+}{\pi }^{-})=[0.33,0.52]$, respectively. Meanwhile, we also calculate the branching fraction of the $B^{-}\to K^{-}{f}_0(980)\to K^{-}{\pi }^{+}{\pi }^{-}$ decay, which is consistent with the experimental results. We suggest that $a_0^0(980)-f_0(980)$ mixing mechanism should be considered when studying the $CP$ violation of the $B$ or $D$ mesons decays theoretically and experimentally.

   hep-phCPC(2022)·1 citation
6. 06*

   Tetraquarks in large-$N_c$ QCD

   Wolfgang Lucha🇦🇹 · Dmitri Melikhov🇷🇺 · Hagop Sazdjian🇫🇷

   The present work reviews the various aspects of the extension of the large-$N_c$ approach, as had been proposed and developed by 't Hooft, to the case of tetraquark states, which are a category of the general class of exotic states, also called multiquark states, whose internal valence-quark structure does not match with that of ordinary hadrons, and which have received, in recent years, many experimental confirmations. The primary question of describing, or probing, on theoretical grounds, multiquark states is first examined. The signature of such states inside Feynman diagrams in relation with their singularities is highlighted. The main mechanisms of formation of tetraquark states, provided by the diquark model and the molecular scheme, are considered together with their specific implications. The properties of tetraquark states at large $N_c$ are analyzed through the Feynman diagrams that describe two-meson scattering amplitudes. It turns out that, in that limit, the possible formation of tetraquark states is mainly due to the mutual interactions of their internal mesonic clusters. These essentially arise from the quark-rearrangement, or quark-interchange, mechanism. In coupled-channel meson-meson scattering amplitudes, one may expect the occurrence of two independent tetraquark states, each having priviledged couplings with the two mesons of their dominant channel. The question of the energy balance of various schemes in the static limit is also analyzed. The clarification of the mechanisms that are at work in the formation of tetraquarks is the main outcome from the large-$N_c$ approach to this problem.

   hep-phPPNP(2021)·33 citations
7. 07*

   An EFT toolbox for baryon and lepton number violating dinucleon to dilepton decays

   Xiao-Gang He🇹🇼 · Xiao-Dong Ma🇹🇼

   In this paper we systematically consider the baryon ($B$) and lepton ($L$) number violating dinucleon to dilepton decays ($pp\to {\ell }^{+}{\ell }^{\prime +},pn\to {\ell }^{+}{\bar{\nu }}^{\prime },nn\to \bar{\nu }{\bar{\nu }}^{\prime }$) with $\Delta B=\Delta L=-2$ in the framework of effective field theory. We start by constructing a basis of dimension-12 (dim-12) operators mediating such processes in the low energy effective field theory (LEFT) below the electroweak scale. Then we consider their standard model effective field theory (SMEFT) completions upwards and their chiral realizations in baryon chiral perturbation theory (B$\chi$PT) downwards. We work to the first nontrivial orders in each effective field theory, collect along the way the matching conditions, and express the decay rates in terms of the Wilson coefficients associated with the dim-12 operators in SMEFT and the low energy constants pertinent to B$\chi$PT. We find the current experimental limits push the associated new physics scale larger than $1-3$ TeV, which is still accessible to the future collider searches. Through weak isospin symmetry, we find the current experimental limits on the partial lifetimes of transitions $pp\to {\ell }^{+}{\ell }^{\prime +},pn\to {\ell }^{+}{\bar{\nu }}^{\prime }$ imply stronger limits on $nn\to \bar{\nu }{\bar{\nu }}^{\prime }$ than their existing lower bounds, which are improved by $2-3$ orders of magnitude. Furthermore, assuming charged mode transitions are also dominantly generated by the similar dim-12 SMEFT interactions, the experimental limits on $pp\to e^{+}{e}^{+},e^{+}{\mu }^{+},{\mu }^{+}{\mu }^{+}$ lead to stronger limits on $pn\to {\ell }_{\alpha }^{+}{\bar{\nu }}_{\beta }$ with $\alpha ,\beta =e,\mu$ than their existing bounds. Conversely, the same assumptions help us to set a lower bound on the lifetime of the experimentally unsearched mode $pp\to e^{+}{\tau }^{+}$ from that of $pn\to e^{+}{\bar{\nu }}_{\tau }$, i.e., ${\Gamma }_{pp\to e^{+}{\tau }^{+}}^{-1}\gtrsim 2\times 10^{34}\mathrm{yrs}$.

   hep-phJHEP(2021)·20 citations
8. 08*

   Phase diagram of interacting pion matter and isospin charge fluctuations

   O. S. Stashko🇺🇦 · O. V. Savchuk🇩🇪 · R. V. Poberezhnyuk🇺🇦 · V. Vovchenko🇺🇸 · M. I. Gorenstein🇺🇦

   Equation of state and electric (isospin) charge fluctuations are studied for matter composed of interacting pions. The pion matter is described by self interacting scalar fields via a ${\varphi }^4-{\varphi }^6$ type Lagrangian. The mean-field approximation is used, and interaction parameters are fixed by fitting lattice QCD results on the isospin density as a function of the isospin chemical potential at zero temperature. Two scenarios for fixing the model parameters -- with and without the first order phase transition -- are considered, both yielding a satisfactory description of the lattice data. Thermodynamic functions and isospin charge fluctuations are studied and systematically compared for these two scenarios, yielding qualitative differences in the behavior of isospin charge susceptibilities. These differences can be probed by lattice simulations at temperatures $T\lesssim 100$ MeV.

   hep-phnucl-thPRC(2021)·4 citations
9. 09*

   Molecular nature of $P_{cs}(4459)$ and its heavy quark spin partners

   C. W. Xiao🇨🇳 · J. J. Wu🇨🇳 · B. S. Zou🇨🇳

   Inspired by the observation of the $P_{cs}(4459)$ state by LHCb recently, we reexamine the results of the interaction of the $J/\psi \Lambda$ channel with its coupled channels, exploiting the coupled channel unitary approach combined with heavy quark spin and local hidden gauge symmetries. By tuning the only free parameter, we find a pole of $(4459.07+i6.89)$ MeV below the ${\bar{D}}^{\ast }{\Xi }_c$ threshold, which was consistent well with the mass and width of the $P_{cs}(4459)$ state. Thus, we assume the $P_{cs}(4459)$ state to be a ${\bar{D}}^{\ast }{\Xi }_c$ bound state with the uncertainties on its degeneracy with $J^P={\frac{1}{2}}^{-}$ and $J^P={\frac{3}{2}}^{-}$. For the degeneracy, it would have two-poles structure, like $P_c(4450)$ before. There is another pole in the $J^P={\frac{1}{2}}^{-}$ sector, $(4310.53+i8.23)$ MeV, corresponding to a deep bound state of $\bar{D}{\Xi }_c$. Furthermore, the previously predicted loose bound states of $\bar{D}{\Xi }_c^{\prime }$, ${\bar{D}}^{\ast }{\Xi }_c^{\prime }$, ${\bar{D}}^{\ast }{\Xi }_c^{\ast }$ with $J=1/2,I=0$ and ${\bar{D}}^{\ast }{\Xi }_c^{\prime }$, $\bar{D}{\Xi }_c^{\ast }$, ${\bar{D}}^{\ast }{\Xi }_c^{\ast }$ with $J=3/2,I=0$ may exist as either bound states or unbound virtual states. We hope that future experiments can search for the ${\bar{D}}^{(\ast )}{\Xi }_c$ molecular states in their dominant decay channels of ${\bar{D}}_s^{(\ast )}{\Lambda }_c$, also in the $J/\psi \Lambda$ and ${\eta }_c\Lambda$ channels to reveal their different nature.

   hep-phPRD(2021)·76 citations
10. 10*

    Scalar and gauge sectors in the 3-Higgs Doublet Model under the S3-symmetry

    M. Gómez-Bock · M. Mondragón🇲🇽 · A. Pérez-Martínez🇲🇽

    We analyse the Higgs sector of an $S_3$ model with three Higgs doublets and no CP violation. After electroweak breaking there are nine physical Higgs bosons, one of which corresponds to the Standard Model one. We study the scalar and gauge sectors of this model, taking into account the conditions set by the minimisation and stability of the potential. We calculate the masses, trilinear and quartic Higgs-Higgs, and Higgs-gauge couplings. We consider two possible alignment scenarios, where only one of the three neutral scalars has couplings to the gauge bosons and corresponds to the SM Higgs, and whose trilinear and quartic couplings reduce exactly to the SM ones. We also obtain numerically the allowed parameter space for the scalar masses in each of the alignment scenarios. We use the calculated trilinear and quartic couplings to find the analytical structure of the one-loop neutral scalar mass matrix, without fermionic contributions. We show that it is possible to have a compact mass spectrum where the contribution to the oblique parameters might be small. We explore some scenarios for the loop contributions to the neutral scalar masses.

    hep-phEPJC(2021)·16 citations
11. 11*

    Search for Axion(-like) Particles in Heavy-Ion Collisions

    Yi Yang🇹🇼 · Cheng-Wei Lin🇹🇼

    We propose a novel way to search for axion(-like) particles in heavy-ion collisions using prompt photons as the probe and the property of conversion between photon and axion(-like) particles under a strong magnetic field generated in the non-central collisions. The expected result reveals that a new phase space region of the coupling constant for photon and axion(-like) particles can be covered in the future high energy nuclear colliders.

    hep-phhep-exJHEP(2022)·4 citations
12. 12*

    EWPD in the SMEFT to dimension eight

    Tyler Corbett🇩🇰 · Andreas Helset🇺🇸 · Adam Martin🇺🇸 · Michael Trott🇩🇰

    We calculate the $\mathcal{O}(⟨H^{†}H{⟩}^2/{\Lambda }^4)$ corrections to LEP electroweak precision data using the geometric formulation of the Standard Model Effective Field Theory (SMEFT). We report our results in simple-to-use interpolation tables that allow the interpretation of this data set to dimension eight for the first time. We demonstrate the impact of these previously unknown terms in the case of a general analysis in the SMEFT, and also in the cases of two distinct models matched to dimension eight. Neglecting such dimension-eight corrections to LEP observables introduces a theoretical error in SMEFT studies. We report some preliminary studies defining such a theory error, explicitly demonstrating the effect of previously unknown dimension-eight SMEFT corrections on LEP observables.

    hep-phJHEP(2021)·98 citations
13. 13*

    Uncovering the High Scale Higgs Singlet Model

    Sally Dawson🇺🇸 · Pier Paolo Giardino🇪🇸 · Samuel Homiller🇺🇸

    The scalar singlet model extends the Standard Model with the addition of a new gauge singlet scalar. We re-examine the limits on the new scalar from oblique parameter fits and from a global fit to precision electroweak observables and present analytic expressions for our results. For the case when the new scalar is much heavier than the weak scale, we map the model onto the dimension-six Standard Model effective field theory (SMEFT) and review the allowed parameter space from unitarity considerations and from the requirement that the electroweak minimum be stable. A global fit to precision electroweak data, along with LHC observables, is used to constrain the parameters of the high scale singlet model and we determine the numerical effects of performing the matching at both tree level and 1-loop.

    hep-phPRD(2021)·32 citations
14. 14*

    The Fermi constant from muon decay versus electroweak fits and CKM unitarity

    Andreas Crivellin🇨🇭 · Martin Hoferichter🇨🇭 · Claudio Andrea Manzari🇨🇭

    The Fermi constant ($G_F$) is extremely well measured through the muon lifetime, defining one of the key fundamental parameters in the Standard Model (SM). Therefore, to search for physics beyond the SM (BSM) via $G_F$, the constraining power is determined by the precision of the second-best independent determination of $G_F$. The best alternative extractions of $G_F$ proceed either via the global electroweak (EW) fit or from superallowed $\beta$ decays in combination with the Cabibbo angle measured in kaon, $\tau$, or $D$ decays. Both variants display some tension with $G_F$ from muon decay, albeit in opposite directions, reflecting the known tensions within the EW fit and hints for the apparent violation of CKM unitarity, respectively. We investigate how BSM physics could bring the three determinations of $G_F$ into agreement using SM effective field theory and comment on future perspectives.

    hep-phhep-exhep-latnucl-ex+1PRL(2021)·77 citations
15. 15*

    Learning to Isolate Muons

    Julian Collado🇺🇸 · Kevin Bauer🇺🇸 · Edmund Witkowski🇺🇸 · Taylor Faucett🇺🇸 · Daniel Whiteson🇺🇸 · Pierre Baldi🇺🇸

    Distinguishing between prompt muons produced in heavy boson decay and muons produced in association with heavy-flavor jet production is an important task in analysis of collider physics data. We explore whether there is information available in calorimeter deposits that is not captured by the standard approach of isolation cones. We find that convolutional networks and particle-flow networks accessing the calorimeter cells surpass the performance of isolation cones, suggesting that the radial energy distribution and the angular structure of the calorimeter deposits surrounding the muon contain unused discrimination power. We assemble a small set of high-level observables which summarize the calorimeter information and close the performance gap with networks which analyze the calorimeter cells directly. These observables are theoretically well-defined and can be studied with collider data.

    ↳ physics.data-anhep-exhep-phJHEP(2020)·14 citations
16. 16*

    Self-Interacting Dark Matter and Small-Scale Gravitational Lenses in Galaxy Clusters

    Daneng Yang🇨🇳 · Hai-Bo Yu🇺🇸

    Recently, Meneghetti et al. reported an excess of small-scale gravitational lenses in galaxy clusters. We study its implications for self-interacting dark matter (SIDM), compared with standard cold dark matter (CDM). We design controlled N-body simulations that incorporate observational constraints. The presence of early-type galaxies in cluster substructures can deepen gravitational potential and reduce tidal mass loss. Both scenarios require a relatively high baryon concentration in the substructure to accommodate the lensing measurements, and their tangential caustics are similar. The SIDM substructure can experience gravothermal collapse and produce a steeper density profile than its CDM counterpart, leading to a larger radial galaxy-galaxy strong lensing cross section, although this effect is hard to observe. Our results indicate SIDM can provide a unified explanation to small-scale lenses in galaxy clusters and stellar motions in dwarf galaxies.

    ↳ astro-ph.GAastro-ph.COhep-phPRD(2021)·64 citations
17. 17*

    Selfinteracting Particle-Antiparticle System of Bosons

    D. Anchishkin🇺🇦 · V. Gnatovskyy🇺🇦 · D. Zhuravel🇺🇦 · V. Karpenko🇺🇦

    Thermodynamic properties of a system of interacting boson particles and antiparticles at finite temperatures are studied within the framework of the thermodynamically consistent Skyrme-like mean-field model. The mean field contains both attractive and repulsive terms. Self-consistency relations between the mean field and thermodynamic functions are derived. We assume conservation of the isospin density for all temperatures. It is shown that, independently of the strength of the attractive mean field, at the critical temperature $T_{\mathrm{c}}$ the system undergoes the phase transition of second-order to the Bose-Einstein condensate, which exists in the temperature interval $0\le T\le T_{\mathrm{c}}$. We obtained that the condensation represents a discontinuity of the derivative of the heat capacity at $T=T_{\mathrm{c}}$, and condensate occurs only for the component with a higher particle-number density in the particle-antiparticle system.

    ↳ nucl-thhep-phquant-phPRC(2022)·6 citations
18. 18*

    Tachyonic Preheating in Palatini $R^2$ Inflation

    Alexandros Karam🇪🇪 · Eemeli Tomberg🇪🇪 · Hardi Veermäe🇪🇪

    We study preheating in the Palatini formalism with a quadratic inflaton potential and an added $\alpha R^2$ term. In such models, the oscillating inflaton field repeatedly returns to the plateau of the Einstein frame potential, on which the tachyonic instability fragments the inflaton condensate within less than an e-fold. We find that tachyonic preheating takes place when $\alpha \gtrsim 10^{13}$ and that the energy density of the fragmented field grows with the rate $\Gamma /H\approx 0.011\times {\alpha }^{0.31}$. The model extends the family of plateau models with similar preheating behaviour. Although it contains non-canonical quartic kinetic terms in the Einstein frame, we show that, in the first approximation, these can be neglected during both preheating and inflation.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2021)·54 citations
19. 19*

    Finite symmetry groups in physics

    Robert A. Wilson🇬🇧

    Finite symmetries abound in particle physics, from the weak doublets and generation triplets to the baryon octet and many others. These are usually studied by starting from a Lie group, and breaking the symmetry by choosing a particular copy of the Weyl group. I investigate the possibility of instead taking the finite symmetries as fundamental, and building the Lie groups from them by means of a group algebra construction. Finite group algebras are the natural algebraic structures in which finite symmetry groups, such as the symmetry group of three generations of elementary fermions, are embedded in Lie groups, that are necessary for the formalism of quantum field theory, including the gauge groups of the fundamental forces. They are also the natural algebraic structures for describing representations of groups, which are used for describing elementary particles and their quantum properties. It is natural therefore to ask the question whether finite group algebras can provide a formal underpinning for the standard model of particle physics, and if so, whether this foundation can explain any aspects of the model that are otherwise unexplained, such as the curious structure of the combined gauge group, or the mixing angles between the different forces. In this paper I investigate the relationships between finite symmetry groups and the gauge groups of each of the fundamental forces individually and in combination, and show that the geometry of representations of the finite groups can be used to predict accurate values for a number of the mixing angles in the standard model, including the electro-weak mixing angle, one lepton mixing angle, one quark mixing angle and one of the CP-violating phases.

    ↳ math.GRhep-ph11 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.