Mon·Jan 24, 2022Monday·January 24, 2022

1. 01*

   Inelastic Dirac Dark Matter

   Anastasiia Filimonova🇳🇱 · Sam Junius🇧🇪 · Laura Lopez Honorez🇧🇪 · Susanne Westhoff🇩🇪

   Feebly interacting thermal relics are promising dark matter candidates. Among them, scenarios of inelastic Dark Matter evade direct detection by suppressed elastic scattering off atomic nuclei. We introduce inelastic Dirac Dark Matter, a new model with two Dirac fermions in the MeV-GeV mass range. At feeble couplings, dark matter can depart from chemical as well as kinetic equilibrium with the Standard Model before freeze-out. In this case, the freeze-out is driven by conversion processes like coscattering, rather than coannihilation. We show that inelastic Dirac relics are consistent with cosmological observations, in particular with nucleosynthesis and the cosmic microwave background. Searches for dark sectors at colliders and fixed-target experiments, in turn, are very sensitive probes. Compared to the strongly constrained pseudo-Dirac scenario, inelastic Dirac Dark Matter offers a new search target for existing and upcoming experiments like Belle II, ICARUS, LDMX and SeaQuest.

   hep-phJHEP(2022)·33 citations
2. 02*

   Flavor alignment of New Physics in light of the $(g-2{)}_{\mu }$ anomaly

   Felix Wilsch🇨🇭

   Addressing the $(g-2{)}_{\mu }$ anomaly and simultaneously being consistent with the tight bounds on $\mu \to e\gamma$ requires a precise alignment of the lepton dipole operator in flavor space. We investigate this alignment condition in the Standard Model Effective Field Theory by considering the Renormalization Group mixing of the relevant operators. We find that semileptonic four-fermion operators, which are likely to yield a sizable contribution to the $(g-2{)}_{\mu }$ anomaly, need to be tightly aligned to the lepton dipole operator and Yukawa coupling. We discuss how New Physics models can comply with these stringent conditions by employing particular dynamical assumptions or using flavor symmetries.

   hep-ph0 citations
3. 03*

   Critical point particle number fluctuations from molecular dynamics

   Volodymyr A. Kuznietsov🇺🇦 · Oleh Savchuk🇺🇦 · Mark I. Gorenstein🇺🇦 · Volker Koch🇺🇸 · Volodymyr Vovchenko🇺🇸

   We study fluctuations of particle number in the presence of critical point by utilizing molecular dynamics simulations of the classical Lennard-Jones fluid in a periodic box. The numerical solution of the $N$-body problem naturally incorporates all correlations, exact conservation laws, and finite size effects, allowing us to study the fluctuation signatures of the critical point in a dynamical setup. We find that large fluctuations associated with the critical point are observed when measurements are performed in coordinate subspace, but, in the absence of collective flow and expansion, are essentially washed out when momentum cuts are imposed instead. We put our findings in the context of event-by-event fluctuations in heavy-ion collisions.

   hep-phcond-mat.stat-mechnucl-thPRC(2022)·27 citations
4. 04*

   Theory and phenomenology of the three-gluon vertex

   J. Papavassiliou🇪🇸 · A. C. Aguilar🇧🇷 · M. N. Ferreira🇧🇷

   The three-gluon vertex is a fundamental ingredient of the intricate QCD dynamics, being inextricably connected to key nonperturbative phenomena, such as the emergence of a mass scale in the gauge sector of the theory. In this presentation, we review the main theoretical properties of the three-gluon vertex in the Landau gauge, obtained from the fruitful synergy between functional methods and lattice simulations. We pay particular attention to the manifestation and origin of the infrared suppression of its main form factors and the associated zero crossing. In addition, we discuss certain characteristic phenomenological applications that require this special vertex as input.

   hep-phhep-latRev.Mex.Fis.Suppl.(2022)·8 citations
5. 05*

   The neutron and proton mass radii from the vector meson photoproduction data on the deuterium target

   Chengdong Han🇨🇳 · Gang Xie🇨🇳 · Wei Kou🇨🇳 · Rong Wang🇨🇳 · Xurong Chen🇨🇳

   In this study, we try to extract the mass radii of the neutron and the proton from the differential cross section data of near-threshold $\omega$ and $\varphi$ photoproductions on deuterium target, which is often approximated as a quasi-free neutron plus a quasi-free proton. The incoherent data of $\omega$ and $\varphi$ photoproductions are provided by CBELSA/TAPS collaboration and LEPS collaboration respectively, where the deuteron is disintegrated in the experiments to measure the properties of individual nucleons. Under the VMD model and the assumption of dipole gravitational form factor, we determined the loosely bound neutron and proton mass radii to be $0.795\pm 0.092(stat.)\pm 0.073(syst.)$ fm and $0.744\pm 0.029(stat.)\pm 0.042(syst.)$ fm respectively from the near-threshold data of $\gamma d\to \omega n(p)$ and $\gamma d\to \omega p(n)$, for the first time. With the near-threshold and incoherent $\varphi$ photoproduction data of $\gamma d\to \varphi pn$, we determined the average mass radius of the bound nucleon (neutron or proton) inside the deuteron to be $0.755\pm 0.039(stat.)\pm 0.039(syst.)$ fm, for the first time. For a comparison study, we also extracted the mass radius of the free proton from the $\omega$ photoproduction on the hydrogen target by CBELSA/TAPS collaboration. Based on our analysis results under the assumptions of VMD model and a low energy QCD theorem, we find that the neutron mass radius is consistent with the proton mass radius within the current statistical uncertainties, and that the nuclear modification on the nucleon mass radius is small inside the deuteron.

   hep-phEPJA(2022)·5 citations
6. 06*

   Leptogenesis from a feebly interacting dark matter sector

   Suresh Chand🇮🇳 · Mariana Frank🇨🇦 · Poulose Poulose🇮🇳

   We perform an analysis of leptogenesis in the context of a simple extension of the Standard Model by two fermions; one charged ($\chi$) and one neutral ($\psi$), in addition to three right-handed neutrinos, $N_i$, interacting through a charged gauge singlet scalar $S$. The dark sector ($\chi$, $\psi$ and $S$) interacts feebly and produces a relic density consistent with measurements. The decay of right-handed neutrinos into the charged scalar $S$ and lepton provides an additional source of CP asymmetry, along with contributing through the virtual exchange of $S$ in the standard decay channel. With this the out-of-equilibrium decay of right-handed neutrinos, combined with lepton number changing scattering processes can generate the required baryon asymmetry of the universe even for right-handed neutrino masses in 10 TeV region, without requiring neutrinos to have degenerate masses.

   hep-phPRD(2022)·3 citations
7. 07*

   Atomic mass, Bjorken variable and scale dependence of quark transport coefficient in Drell-Yan process for proton incident on nucleus

   Wei-Jie Xu🇨🇳 · Tian-Xing Bai🇨🇳 · Chun-Gui Duan🇨🇳

   By means of the nuclear parton distributions determined without the fixed-target Drell-Yan experimental data and the analytic expression of quenching weight based on BDMPS formalism, a next-to-leading order analyses are performed on the Drell-Yan differential cross section ratios from Fermilab E906 and E866 Collaborations. It is found that the calculated results with only the nuclear effects of parton distribution are not in agreement with the E866 and E906 experimental data. The incoming parton energy loss effect can not be ignored in the nuclear Drell-Yan reactions. The predicted results indicate that with the quark transport coefficient as a constant, the suppression due to the target nuclear geometry effect is approximately 19.24% for the quark transport coefficient. It is shown that we should consider the target nuclear geometry effect in studying the Drell-Yan reaction on nuclear targets. On the basis of Bjorken variable and scale dependence of the quark transport coefficient, the atomic mass dependence is incorporated. The quark transport coefficient is determined as a function of the atomic mass, Bjorken variable $x_2$ and scale $Q^2$ by the global fit of the experimental data. The determined constant factor ${\hat{q}}_0$ of the quark transport coefficient is $0.061\pm 0.004\mathrm{Ge}{\mathrm{V}}^2/fm$. It is found that the atomic mass dependence has a remarkable impact on the constant factor ${\hat{q}}_0$ in the quark transport coefficient in cold nuclear matter.

   hep-phCPC(2023)·1 citation
8. 08*

   Signature of the gluon orbital angular momentum

   Shohini Bhattacharya🇺🇸 · Renaud Boussarie🇫🇷 · Yoshitaka Hatta🇺🇸

   We propose a novel observable for the experimental detection of the gluon orbital angular momentum (OAM) that constitutes the proton spin sum rule. We consider longitudinal double spin asymmetry in exclusive dijet production in electron-proton scattering and demonstrate that the $\cos \varphi$ azimuthal angle correlation between the scattered electron and proton is a sensitive probe of the gluon OAM at small-$x$ and its interplay with the gluon helicity. We also present a numerical estimate of the cross section for the kinematics of the Electron-Ion Collider.

   hep-phhep-exPRL(2022)·55 citations
9. 09*

   Tsallis statistics and thermofractals: applications to high energy and hadron physics

   Eugenio Megias🇪🇸 · Evandro Andrade II🇧🇷 · Airton Deppman🇧🇷 · Arnaldo Gammal🇧🇷 · Debora P. Menezes🇧🇷 · Tiago Nunes da Silva🇧🇷 · Varese S. Timóteo🇧🇷

   We study the applications of non-extensive Tsallis statistics to high energy and hadron physics. These applications include studies of $pp$ collisions, equation of state of QCD, as well as Bose-Einstein condensation. We also analyze the connections of Tsallis statistics with thermofractals, and address some of the conceptual aspects of the fractal approach, which are expressed in terms of the renormalization group equation and the self-energy corrections to the parton mass. We associate these well-known concepts with the origins of the fractal structure in the quantum field theory.

   hep-phcond-mat.quant-gasnucl-thInt.J.Mod.Phys.A(2023)·5 citations
10. 10*

    Effective electroweak Hamiltonian in the gradient-flow formalism

    Robert V. Harlander🇩🇪 · Fabian Lange🇩🇪

    The effective electroweak Hamiltonian in the gradient-flow formalism is constructed for the current-current operators through next-to-next-to-leading order QCD. The results are presented for two common choices of the operator basis. This paves the way for a consistent matching of perturbatively evaluated Wilson coefficients and non-perturbative matrix elements evaluated by lattice simulations.

    ↳ hep-lathep-phPRD(2022)·19 citations
11. 11*

    Search for the muon electric dipole moment using frozen-spin technique at PSI

    K.S. Khaw🇨🇳 · A. Adelmann🇨🇭 · M. Backhaus🇨🇭 · N. Berger🇩🇪 · M. Daum🇨🇭 · M. Giovannozzi🇨🇭 · K. Kirch🇨🇭 · A. Knecht🇨🇭 · A. Papa🇨🇭 · C. Petitjean🇨🇭 · F. Renga🇮🇹 · M. Sakurai🇨🇭 · P. Schmidt-Wellenburg🇨🇭

    The presence of a permanent electric dipole moment in an elementary particle implies Charge-Parity symmetry violation and thus could help explain the matter-antimatter asymmetry observed in our universe. Within the context of the Standard Model, the electric dipole moment of elementary particles is extremely small. However, many Standard Model extensions such as supersymmetry predict large electric dipole moments. Recently, the muon electric dipole moment has become a topic of particular interest due to the tensions in the magnetic anomaly of the muon and the electron, and hints of lepton-flavor universality violation in B-meson decays. In this article, we discuss a dedicated effort at the Paul Scherrer Institute in Switzerland to search for the muon electric dipole moment using a 3-T compact solenoid storage ring and the frozen-spin technique. This technique could reach a sensitivity of $6\times 10^{-23}$ $e\cdot$cm after a year of data taking with the $p=125$ MeV/$c$ muon beam at the Paul Scherrer Institute. This allows us to probe various Standard Model extensions not reachable by traditional searches using muon $g-2$ storage rings.

    ↳ hep-exhep-phPoS(2022)·10 citations
12. 12*

    Bottoms Up: Standard Model Effective Field Theory from a Model Perspective

    Philip Bechtle🇩🇪 · Cristin Chall🇩🇪 · Martin King🇩🇪 · Michael Kraemer🇩🇪 · Peter Maettig🇩🇪 · Michael Stoeltzner🇺🇸

    Experiments in particle physics have hitherto failed to produce any significant evidence for the many explicit models of physics beyond the Standard Model (BSM) that had been proposed over the past decades. As a result, physicists have increasingly turned to model-independent strategies as tools in searching for a wide range of possible BSM effects. In this paper, we describe the Standard Model Effective Field Theory (SM-EFT) and analyse it in the context of the philosophical discussions about models, theories, and (bottom-up) effective field theories. We find that while the SM-EFT is a quantum field theory, assisting experimentalists in searching for deviations from the SM, in its general form it lacks some of the characteristic features of models. Those features only come into play if put in by hand or prompted by empirical evidence for deviations. Employing different philosophical approaches to models, we argue that the case study suggests not to take a view on models that is overly permissive because it blurs the lines between the different stages of the SM-EFT research strategies and glosses over particle physicists' motivations for undertaking this bottom-up approach in the first place. Looking at EFTs from the perspective of modelling does not require taking a stance on some specific brand of realism or taking sides in the debate between reduction and emergence into which EFTs have recently been embedded.

    ↳ physics.hist-phhep-ph7 citations
13. 13*

    Clock Fields and Logarithmic Decay of Dark Energy

    Robert Brandenberger🇨🇦 · Vincent Comeau🇨🇦 · Leonardo Fossati🇨🇭 · Lavinia Heisenberg (McGill, ETH, Heidelberg)🇩🇪

    We investigate the physical measurability of the infrared instability of a de Sitter phase in the formalism recently proposed by Kitamoto et al.. We find that the logarithmic decay of the effective cosmological constant is only measurable if an additional clock field is introduced.

    ↳ hep-thastro-ph.COgr-qchep-ph5 citations
14. 14*

    Cosmological dynamics of multifield dark energy

    Johannes R. Eskilt🇳🇴 · Yashar Akrami🇺🇸 · Adam R. Solomon🇨🇦 · Valeri Vardanyan🇯🇵

    We numerically and analytically explore the background cosmological dynamics of multifield dark energy with highly nongeodesic or "spinning" field-space trajectories. These extensions of standard single-field quintessence possess appealing theoretical features and observable differences from the cosmological standard model. At the level of the cosmological background, we perform a phase-space analysis and identify approximate attractors with late-time acceleration for a wide range of initial conditions. Focusing on two classes of field-space geometry, we derive bounds on parameter space by demanding viable late-time acceleration and the absence of gradient instabilities, as well as from the de Sitter swampland conjecture.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2022)·27 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.