Mon·Jul 26, 2021Monday·July 26, 2021

1. 01*

   Probing scalar dark matter oscillations with neutrino oscillations

   Marta Losada🇦🇪 · Yosef Nir🇮🇱 · Gilad Perez🇮🇱 · Yogev Shpilman🇮🇱

   If ultra-light dark matter (ULDM) exists and couples to neutrinos, it can be discovered via time-periodic variations in the neutrino mass and mixing parameters. We analyze the current bounds on such a scenario and establish the sensitivity expected for both time-averaged and time-resolved modulations in future neutrino oscillation experiments. We place a special emphasis in our analysis on time modulations of the CP violating mixing phase. We illustrate with a toy model the case where the leading modulation effect can be CP violating while the effect on CP conserving parameters is suppressed. We show a unique imprint that a time averaged CP violating modulation of ULDM can leave in neutrino oscillations, while direct CP asymmetries vanish.

   hep-phhep-exJHEP(2022)·48 citations
2. 02*

   The charm of 331

   Andrzej J. Buras🇩🇪 · Pietro Colangelo🇮🇹 · Fulvia De Fazio🇮🇹 · Francesco Loparco🇮🇹

   We perform a detailed analysis of flavour changing neutral current processes in the charm sector in the context of 331 models. As pointed out recently, in the case of $Z^{\prime }$ contributions in these models there are no new free parameters beyond those already present in the $B_{d,s}$ and $K$ meson systems analyzed in the past. As a result, definite ranges for new Physics (NP) effects in various charm observables could be obtained. While generally NP effects turn out to be small, in a number of observables they are much larger than the tiny effects predicted within the Standard Model. In particular we find that the branching ratio of the mode $D^0\to {\mu }^{+}{\mu }^{-}$, despite remaining tiny, can be enhanced by 6 orders of magnitude with respect to the SM. We work out correlations between this mode and rare $B_{d,s}$ and $K$ decays. We also discuss neutral charm meson oscillations and CP violation in the charm system. In particular, we point out that 331 models provide new weak phases that are a necessary condition to have non-vanishing CP asymmetries. In the case of $\Delta A_{CP}$, the difference between the CP asymmetries in $D^0\to K^{+}{K}^{-}$ and $D^0\to {\pi }^{+}{\pi }^{-}$, we find that agreement with experiment can be obtained provided that two conditions are verified: the phases in the ranges predicted in 331 models and large hadronic matrix elements.

   hep-phhep-exhep-latJHEP(2021)·37 citations
3. 03*

   Statistical evaluation of fitted models applied to ${\mathbf{p}}_{\mathbf{t}}$ spectrum data from 5 TeV and 13 TeV $\mathbf{p}$-$\mathbf{p}$ collisions at the large hadron collider

   Thomas A. Trainor🇺🇸

   In a recent analysis of high-statistics $p_t$ spectra from 5 and 13 TeV $p$-$p$ collisions a two-component (soft+hard) model (TCM) of hadron production near midrapidity, based on fixed model functions independent of collision multiplicity $n_{ch}$ or event selection criteria, was employed as a reference to determine data biases induced by the selection criteria. As in previous studies the fixed TCM accurately isolated jet-related and nonjet contributions to spectra. It was observed that two selection criteria (V0M and SPD), based on different pseudorapidity $\eta$ acceptances, bias the spectrum hard component (jet fragment distribution) in different but complementary ways whereas the soft component is not significantly biased. In the present study TCM model functions are adjusted (i.e. fitted) to accommodate data. The effect of selection bias is then represented by smooth evolution of model parameters with $n_{ch}$. To evaluate the quality of model fits, Z-scores (data-model differences divided by statistical uncertainties) are evaluated and compared with data/model ratios that are often used for such comparisons. Based on Z-scores the variable TCM is compared with two other frequently-invoked models: the Tsallis model and the blast-wave model as they have been recently applied to the same spectrum data. The results are relevant to recent claims that collectivity (various flow manifestations) as a possible manifestation of QGP formation is observed in small systems. Data systematics suggest that these $p$-$p$ $p_t$ spectra are consistent with conventional QCD.

   hep-ph7 citations
4. 04*

   Vector Portal Pseudo-Goldstone Dark Matter

   Ian Chaffey🇺🇸

   We present a model of pseudo-Goldstone dark matter that interacts through a light vector mediator based on a spontaneously broken $SU(2)$ dark sector. The dark matter mass is induced by the explicit breaking of the dark $SU(2)$ symmetry. A residual global $U(1)$ symmetry prevents dark matter decay. The behavior of this model is studied under the assumption that the observed dark matter relic abundance is due to thermal freeze-out. We consider self-interaction targets for small scale structure anomalies and the possibility of interacting with the Standard model through the vector mediator.

   hep-phastro-ph.CO0 citations
5. 05*

   Spontaneous chiral symmetry breaking in holographic soft wall models

   Alfonso Ballon-Bayona🇧🇷 · Luis A. H. Mamani🇧🇷 · Diego M. Rodrigues🇧🇷

   We investigate non-linear extensions of the holographic soft wall model proposed by Karch, Katz, Son and Stephanov [1] including non-minimal couplings in the five-dimensional action. The non-minimal couplings bring a new parameter $a_0$ which controls the transition between spontaneous and explicit symmetry breaking near the limit of massless quarks (the chiral limit). In the physical region (positive quark mass), we show that above a critical value of the parameter $a_0$ the chiral condensate $⟨\bar{q}q⟩$ is finite in the chiral limit, signifying spontaneous chiral symmetry breaking. This result is supported by the lightest states arising in the spectrum of the pseudoscalar mesons, which become massless in the chiral limit and are therefore intrepreted as Nambu-Goldstone bosons. Moreover, the decay constants of the pseudoscalar mesons also support this conclusion, as well as the Gell-Mann-Oakes-Renner (GOR) relation satisfied by the lightest states. We also calculate the spectrum of scalar, vector, and axial-vector mesons with their corresponding decay constants. We describe the evolution of masses and decay constants with the increasing of the quark mass and for the physical mass we compare our results against available experimental data. Finally, we do not find instabilities in our model for the physical region (positive quark mass).

   hep-phhep-lathep-thPRD(2021)·18 citations
6. 06*

   Investigation of the $X(4020)$ peak in the $D^{\ast }{\bar{D}}^{\ast }$ and $\pi h_c$ channels

   Shuntaro Sakai🇯🇵

   In this paper, the nature of $X(4020)$ observed in the vicinity of the $D^{\ast }{\bar{D}}^{\ast }$ threshold of the $\pi h_c$ and $D^{\ast }{\bar{D}}^{\ast }$ distributions is studied. Using a model containing one bare-particle state with the $\pi h_c$ and $D^{\ast }{\bar{D}}^{\ast }$ one-loop self energies, we make a fit to the $\pi h_c$ and $D^{\ast }{\bar{D}}^{\ast }$ distributions of the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{h}_c$ and $e^{+}{e}^{-}\to {\pi }^{-}{D}^{\ast +}{\bar{D}}^{\ast 0}$ reactions reported by the BESIII Collaboration. It is found that both structures seen in the $\pi h_c$ and $D^{\ast }{\bar{D}}^{\ast }$ channels are described well with one resonant state which can be associated with $X(4020)$ while the obtained $X(4020)$ mass and width are found to be larger than those in the latest PDG. We evaluate the scattering length and effective range of the $S$-wave $D^{\ast }{\bar{D}}^{\ast }$ pair with spin $J=1$ related to the $X(4020)$ properties which can be tested with model calculations or future lattice QCD study. Our analysis suggests that a large part of $X(4020)$ may come from a bare-particle state originating from some short-range dynamics other than the $D^{\ast }{\bar{D}}^{\ast }$ channel.

   hep-ph2 citations
7. 07*

   Nonlinear corrections on the parameterization methods

   G.R.Boroun🇮🇷 · B.Rezaei🇮🇷

   We present non-linear corrections (NLC) to the distribution functions at low values of $x$ and $Q^2$ using the parametrization $F_2(x,Q^2)$ and $F_L(x,Q^2)$. We use a direct method to extract non-linear corrections to the ratio of structure functions and the reduced cross section in the next-to-next-to-leading order (NNLO) approximation with respect to the parametrization method (PM). Comparison between the non-linear results with the bounds in color dipole model (CDM) and HERA data indicate the consistency of the non-linear behavior of the gluon distribution function at low-$x$ and low-$Q^2$. The non-linear longitudinal structure functions are comparable with the H1 Collaboration data in a wide range of $Q^2$ values. Consequently, the non-linear corrections at NNLO approximation to the reduced cross sections at low and moderate $Q^2$ values show good agreement with the HERA combined data. These results at low $x$ and low $Q^2$ can be applied to the LHeC region for analyses of ultra-high-energy processes.

   hep-phEPJC(2021)·7 citations
8. 08*

   Analysis of three-body charmed B meson decays under the factorization-assisted topological-amplitude approach

   Si-Hong Zhou🇨🇳 · Run-Hui Li🇨🇳 · Zheng-Yi Wei🇨🇳 · Cai-Dian Lü

   We analyze the quasi-two-body charmed $B$ decays $B_{(s)}^{+,0}\to D_{(s)}^{\ast }{P}_2\to D_{(s)}{P}_1{P}_2$ with $P_{1,2}$ as a pion or kaon. The intermediate processes $B_{(s)}\to D_{(s)}^{\ast }{P}_2$ are calculated with the factorization-assisted topological-amplitude approach and the resonant effects are calculated with the Breit-Wigner formalism. Taking all p-wave resonance states ${\bar{D}}_{(s)}^{\ast }$ into consideration, we present the related branching fractions, calculate the Breit-Wigner-Tail effects, and investigate the flavor $SU(3)$ breaking effects. Most of our branching fractions are consistent with the perturbative QCD approach's predictions as well as the current experimental data. With more precision calculation of the intermediate two body charmed B meson decays, our quasi-two-body B decays calculation has significantly less theoretical uncertainty than the perturbative QCD approach. Many of those channels without any experimental data will be confronted with the future more accurate experiment measurements. Our results of the Breit-Wigner-tail effects also agree with the experimental very well. In $B^0$ decays this effect can reach approximately to $5\%$. It is also found that the Breit-Wigner-tail effects are not sensitive to the widths of their corresponding resonances. The flavor $SU(3)$ symmetry breaking effect is also investigated.

   hep-phPRD(2021)·20 citations
9. 09*

   Production of three isolated photons in the high-energy factorization approach

   Vladimir Saleev🇷🇺

   We study large-$p_T$ three-photon production at the LHC at the center-of-mass energy $\sqrt{s}=8$ TeV. We use the LO approximation of the parton Reggeization approach consistently merged with the real NLO corrections. For numerical calculations use the parton-level generator KaTie and modified KMR-type unintegrated parton distribution functions. We find good agreement between our predictions and data with the same accuracy as in the NNLO calculations based on the collinear parton model of QCD. At higher energies ($\sqrt{s}=13$ and 27 TeV) parton Reggeization approach predicts larger cross sections, up to $\sim 10$ \% and $\sim 20$ \%, respectively.

   hep-phSciPost Phys.Proc.(2022)·3 citations
10. 10*

    Sensitivity of future linear $e^{+}{e}^{-}$ colliders to processes of dark matter production with light mediator exchange

    Jan Kalinowski🇵🇱 · Wojciech Kotlarski🇵🇱 · Krzysztof Mekala🇵🇱 · Pawel Sopicki🇵🇱 · Aleksander Filip Zarnecki🇵🇱

    As any $e^{+}{e}^{-}$ scattering process can be accompanied by a hard photon emission from the initial state radiation, the analysis of the energy spectrum and angular distributions of those photons can be used to search for hard processes with an invisible final state. Thus high energy $e^{+}{e}^{-}$ colliders offer a unique possibility for the most general search of dark matter (DM) based on the mono-photon signature. We consider production of DM particles at the International Linear Collider (ILC) and Compact Linear Collider (CLIC) experiments via a light mediator exchange. Detector effects are taken into account within the DELPHES fast simulation framework. Limits on the light DM production in a simplified model are set as a function of the mediator mass and width based on the expected two-dimensional distributions of the reconstructed mono-photon events. The experimental sensitivity is extracted in terms of the DM production cross section. Limits on the mediator couplings are then presented for a wide range of mediator masses and widths. For light mediators, for masses up to the centre-of-mass energy of the collider, coupling limits derived from the mono-photon analysis are more stringent than those expected from direct resonance searches in decay channels to SM particles.

    hep-phEPJC(2021)·37 citations
11. 11*

    Addendum: Refined bounds on MeV-scale thermal dark sectors from BBN and the CMB

    Nashwan Sabti🇬🇧 · James Alvey🇬🇧 · Miguel Escudero🇩🇪 · Malcolm Fairbairn🇬🇧 · Diego Blas🇪🇸

    Very recently, the LUNA collaboration has reported a new measurement of the $d+p\to {}^3\text{He}+\gamma$ reaction rate, which plays an important role in the prediction of the primordial deuterium abundance at the time of BBN. This new measurement has triggered a new set of global BBN analyses within the context of the Standard Model. In this addendum to JCAP 01 (2020) 004 (arXiv:1910.01649), we consider the implications of these new results for our constraints on MeV-scale dark sectors. Importantly, we find that our bounds in the BBN-only and Planck-only analyses are insensitive to these updates. Similarly, we find that our constraints derived using BBN and CMB data simultaneously are not significantly modified for neutrinophilic particles. The bounds on electrophilic dark sector states, however, can vary moderately when combining BBN and CMB observations. We present updated results for all the relevant light dark sector states, calculated using the rates obtained by the leading groups performing standard BBN analyses.

    hep-phastro-ph.COJCAP(2021)·46 citations
12. 12*

    A new method to extract the valence transversity distributions

    Mauro Anselmino🇮🇹 · Raj Kishore🇨🇳 · Asmita Mukherjee🇮🇳

    A new method is suggested for the extraction of $u$-quark and $d$-quark transversity distributions, using single spin asymmetry (SSA) data in semi-inclusive deep inelastic scattering (SIDIS) processes, where they couple to the Collins or the di-hadron fragmentation functions. We discuss a recent suggestion to extract the transversity distribution using the concept of difference asymmetries and their ratios, which avoids the requirement of Collins function. We suggest new measurements, involving ratios of polarized cross-sections, that would directly probe the ratio $h_1^{d_v}/h_1^{u_v}$. We also show some numerical estimates.

    hep-phSciPost Phys.Proc.(2022)·0 citations
13. 13*

    Shadow generalized parton distributions: a practical approach to the deconvolution problem of DVCS

    V. Bertone🇫🇷 · H. Dutrieux🇫🇷 · C. Mezrag🇫🇷 · H. Moutarde🇫🇷 · P. Sznajder🇵🇱

    Deeply virtual Compton scattering (DVCS) attracts a lot of interest due to its sensitivity to generalized parton distributions (GPDs) which provide a rich access to the partonic structure of hadrons. However, the practical extraction of GPDs for this channel requires a deconvolution procedure, whose feasibility has been disputed. We provide a practical approach to this problem based on a next-to-leading order analysis and a careful study of evolution effects, by exhibiting shadow GPDs with arbitrarily small imprints on DVCS observables at current and future experimental facilities. This shows that DVCS alone will not allow for a model independent extraction of GPDs and a multi-channel analysis is required for this purpose.

    hep-phhep-exhep-latnucl-exSciPost Phys.Proc.(2022)·4 citations
14. 14*

    Quantifying the Quark Gluon Plasma

    Derek Everett🇺🇸

    The study of heavy-ion collisions presents a challenge to both theoretical and experimental nuclear physics. Due to the extremely short lifetime and small size of the collision system, disentangling information provided by experimental observables and progress in physical insight requires the careful application of plausible reasoning. I apply a program of statistical methodologies, primarily Bayesian, to quantify properties of the medium in specific models, as well as compare and criticize differing models of the system. Of particular interest are estimations of the specific shear and bulk viscosities, where we find that information carried by the experimental data is still limited. In particular we find a large sensitivity to prior assumptions at high temperatures. Moreover, sensitivities to model assumptions are present at low temperatures, and this source of model uncertainty is propagated with model averaging and model mixing.

    hep-phnucl-th3 citations
15. 15*

    One-loop corrections to ALP couplings

    J. Bonilla🇪🇸 · I. Brivio🇩🇪 · M.B. Gavela🇪🇸 · V. Sanz🇪🇸

    The plethora of increasingly precise experiments which hunt for axion-like particles (ALPs), as well as their widely different energy reach, call for the theoretical understanding of ALP couplings at loop-level. We derive the one-loop contributions to ALP-SM effective couplings, including finite corrections. The complete leading-order -- dimension five -- effective linear Lagrangian is considered. The ALP is left off-shell, which is of particular impact on LHC and accelerator searches of ALP couplings to $\gamma \gamma$, $ZZ$, $Z\gamma$, $WW$, gluons and fermions. All results are obtained in the covariant $R_{\xi }$ gauge. A few phenomenological consequences are also explored as illustration, with flavour diagonal channels in the case of fermions: in particular, we explore constraints on the coupling of the ALP to top quarks, that can be extracted from LHC data, from astrophysical sources and from Dark Matter direct detection experiments such as PandaX, LUX and XENON1T. Furthermore, we clarify the relation between alternative ALP bases, the role of gauge anomalous couplings and their interface with chirality-conserving and chirality-flip fermion interactions, and we briefly discuss renormalization group aspects.

    hep-phJHEP(2021)·96 citations
16. 16*

    Generalising Holographic Superconductors

    Andrea Donini🇪🇸 · Victor Enguita-Vileta🇪🇸 · Fabian Esser🇪🇸 · Veronica Sanz🇪🇸

    In this paper we propose a generalised holographic framework to describe superconductors. We first unify the description of s-, p- and d-wave superconductors in a way that can be easily promoted to higher spin. Using a semi-analytical procedure to compute the superconductor properties, we are able to further generalise the geometric description of the hologram beyond the AdS-Schwarzschild Black Hole paradigm, and propose a set of higher-dimensional metrics which exhibit the same universal behaviour. We then study the properties of the condensate and the scaling of the critical temperature with the parameters of the higher-dimensional theory, reproducing existing results in the literature and extending them to include a possible description of the newly observed f-wave superconducting systems.

    ↳ hep-thcond-mat.supr-conhep-phAdv.High Energy Phys.(2022)·5 citations
17. 17*

    The bottomonium melting from screening correlators at high temperature

    Peter Petreczky🇺🇸 · Sayantan Sharma🇮🇳 · Johannes Heinrich Weber🇩🇪

    We study the bottomonium screening masses in a 2+1 flavor QCD medium on the lattice using the Highly Improved Staggered Quark(HISQ) discretization for the quarks. We focus on a wide temperature range in the region $350\mathrm{MeV}\le T<1000\mathrm{MeV}$, and perform our calculations on three different lattice spacings to control the lattice cut-off effects, corresponding to temporal lattice extent of $N_{\tau }=8,10,12$. From a detailed study of the temperature dependence of screening masses we conclude that while the ${\eta }_b(1S)$ and ${\rm Y}(1S)$ states melt at $T>500$ MeV, the scalar and axial-vector states ${\chi }_{b0}(1P)$ and $h_b(1P)$ melt already at $T>350$ MeV.

    ↳ hep-lathep-phPRD(2021)·23 citations
18. 18*

    Investigations into the characteristics and influences of nonequilibrium evolution

    Xiaobing Li🇨🇳 · Mingmei Xu🇨🇳 · Yanhua Zhang🇺🇸 · Zhiming Li🇨🇳 · Yu Zhou🇺🇸 · Jinghua Fu🇨🇳 · Yuanfang Wu🇨🇳

    In order to estimate qualitatively the influence of nonequilibrium evolution in relativistic heavy ion collisions, we use the three dimensional Ising model with Metropolis algorithm to study the evolution from nonequilibrium to equilibrium on the phase boundary. The evolution of order parameter approaches its equilibrium value exponentially, the same as that given by Langevin equation. The average relaxation time is defined which is demonstrated to well represent the relaxation time in dynamical equations. It is shown that the average relaxation time at critical temperature diverges as the zth power of system size. The third and the fourth cumulants of order parameter during the nonequilibrium evolution could be either positive or negative, depending on the observation time, consistent with dynamical models at T > Tc. It is found that the nonequilibrium evolution at T > Tc lasts very short, and the influence is weaker than that at T < Tc. Those qualitative features are instructive to determine experimentally the critical point and the phase boundary of QCD.

    ↳ cond-mat.stat-mechhep-phhep-thPRC(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.