Fri·Aug 6, 2021Friday·August 6, 2021

1. 01*

   Quasi-Eclectic Modular Flavor Symmetries

   Mu-Chun Chen🇺🇸 · Victor Knapp-Perez🇲🇽 · Mario Ramos-Hamud🇲🇽 · Saul Ramos-Sanchez🇲🇽 · Michael Ratz🇺🇸 · Shreya Shukla🇺🇸

   Modular flavor symmetries provide us with a new, promising approach to the flavor problem. However, in their original formulation the kinetic terms of the standard model fields do not have a preferred form, thus introducing additional parameters, which limit the predictive power of this scheme. In this work, we introduce the scheme of quasi-eclectic flavor symmetries as a simple fix. These symmetries are the direct product of a modular and a traditional flavor symmetry, which are spontaneously broken to a diagonal modular flavor subgroup. This allows us to construct a version of Feruglio's model with the Kaehler terms under control. At the same time, the starting point is reminiscent of what one obtains from explicit string models.

   hep-phPLB(2022)·42 citations
2. 02*

   Condensates of ultralight axions and a link of leptonic scales to dark matter

   Janning Meinert🇩🇪

   The mass of ultralight axions is determined in order to get the explicit U(1)${}_A$ symmetry breaking scale $\Lambda$ at a Peccei-Quinn scale of the magnitude of the Planck mass. It is assumed that the dominant contribution to the mass of a galaxy with low surface brightness is only determined by one axionic species in the sense of fuzzy dark matter (lumps). For rotation curve fits to galactic rotation curves, therefore the Soliton-Navarro-Frenk-White model is used, which assumes a condensate core plus correlated axions in the halo according to the solution of the Poisson-Schrödinger system. In addition, three commonly used mass density profiles are considered: Navarro-Frenk-White, pseudo-isothermal and the Burkert model. An axion mass $m_a$ of $0.675\times 10^{-23}$eV is extracted, which reproduces previous results in the literature. This implies an effective Yang-Mills scale of $\Lambda \sim 287$ eV, which is only a factor of $15$ smaller than the Yang-Mills scale of an SU(2) theory that is used to describe the first lepton family. The cosmological model SU(2)${}_{\mathrm{CMB}}$ suggests that three SU(2) Yang-Mills theories, each for the formation of the lepton doublets (e,${\nu }_e$), ($\mu$,${\nu }_{\mu }$), and ($\tau$,${\nu }_{\tau }$) are equally responsible for contributing to the current density of dark matter. Parameters of an isolated lump, such as the gravitational Bohr radius or the virial mass, are determined solely by the Planck mass and the corresponding lepton mass. If the dominant constituent of the dark mass contained in a galaxy is represented by e-lumps, a mixture of $\tau -$ and $\mu$-lumps could possibly explain the presence of massive compact objects in galactic centers, and $\tau$-lumps could be related to globular clusters and the halo mass. This might provide a theoretical explanation for the mass gap between stellar and super massive black holes.

   hep-phhep-th0 citations
3. 03*

   Dynamical diquarks in the ${\mathbf{\gamma }}^{(\ast )}\mathbf{p}\to \mathbf{N}(1535){\frac{1}{2}}^{-}$ transition

   Khépani Raya🇨🇳 · L. X. Gutiérrez-Guerrero🇲🇽 · Adnan Bashir🇲🇽 · Lei Chang🇨🇳 · Zhu-Fang Cui🇨🇳 · Ya Lu🇨🇳 · Craig D. Roberts🇨🇳 · Jorge Segovia🇪🇸

   The ${\gamma }^{(\ast )}+p\to N(1535){\frac{1}{2}}^{-}$ transition is studied using a symmetry-preserving regularisation of a vector$\otimes$vector contact interaction (SCI). The framework employs a Poincaré-covariant Faddeev equation to describe the initial and final state baryons as quark+di\-quark composites, wherein the diquark correlations are fully dynamical, interacting with the photon as allowed by their quantum numbers and continually engaging in breakup and recombination as required by the Faddeev kernel. The presence of such correlations owes largely to the mechanisms responsible for the emergence of hadron mass; and whereas the nucleon Faddeev amplitude is dominated by scalar and axial-vector diquark correlations, the amplitude of its parity partner, the $N(1535){\frac{1}{2}}^{-}$, also contains sizeable pseudoscalar and vector diquark components. It is found that the ${\gamma }^{(\ast )}+p\to N(1535){\frac{1}{2}}^{-}$ helicity amplitudes and related Dirac and Pauli form factors are keenly sensitive to the relative strengths of these diquark components in the baryon amplitudes, indicating that such resonance electrocouplings possess great sensitivity to baryon structural details. Whilst SCI analyses have their limitations, they also have the virtue of algebraic simplicity and a proven ability to reveal insights that can be used to inform more sophisticated studies in frameworks with closer ties to quantum chromodynamics.

   hep-phhep-latnucl-exnucl-thEPJA(2021)·43 citations
4. 04*

   Loop effect with vector mediator in the coherent neutrino-nucleus scattering

   Wei Chao🇨🇳 · Tong Li🇨🇳 · Jiajun Liao🇨🇳 · Min Su🇨🇳

   The observation of the coherent elastic neutrino-nucleus scattering (CE$\nu$NS) provides us opportunities to explore a wide class of new physics. In the Standard Model (SM), the CE$\nu$NS process arises from the vector and axial-vector neutral currents through the exchange of $Z$ boson and the axial-vector current contribution turns out to be subdominant. It is thus natural to consider the extra contributions to CE$\nu$NS from more generic new physics beyond the SM with (axial-)vector interactions associated with a new vector mediator $Z^{\prime }$. Besides the ordinary CE$\nu$NS, the active neutrinos can convert into a new exotic fermion $\chi$ through the process $\nu N\to \chi N$ mediated by $Z^{\prime }$ without violating the coherence. It would be interesting to consider the implication of this conversion for the new fermion sector beyond the SM. We consider the framework of a simplified neutrino model in which a new Dirac fermion $\chi$ interacts with active neutrinos and a leptophobic vector mediator $Z^{\prime }$. We evaluate both the tree-level and loop-level contributions to the CE$\nu$NS and in particular the loop diagrams produce active neutrino elastic scattering process $\nu N\to \nu N$ with the fermion $\chi$ inside the loops. When the interaction between $Z^{\prime }$ and the SM quarks is vector type and axial-vector type, the CE$\nu$NS processes are respectively dominated by the tree-level and loop-level contributions. We investigate the constraints on the model parameters by fitting to the COHERENT data, assuming a wide range of $m_{\chi }$. The parameter space with $m_{\chi }$ larger than the maximal energy of incoming neutrinos can be constrained by including the loop-level contribution. More importantly, the inclusion of loop diagrams can place constraint on axial-vector interaction whose tree-level process is absent in the coherent neutrino-nucleus scattering.

   hep-phPRD(2021)·6 citations
5. 05*

   Collision energy dependence of the critical end point from baryon number fluctuations in the Linear Sigma Model with quarks

   Alejandro Ayala🇲🇽 · Bilgai Almeida Zamora🇲🇽 · J. J. Cobos-Martínez🇲🇽 · S. Hernández-Ortiz🇺🇸 · L. A. Hernández🇿🇦 · Alfredo Raya🇲🇽 · María Elena Tejeda-Yeomans🇲🇽

   We show that the Linear Sigma Model with quarks produces an effective description of the QCD phase diagram and of the system's equilibrium distribution properties that deviate from those of the Hadron Resonance Gas Model. The deviation is due to the inclusion of plasma screening properties, encoded in the contribution of the ring diagrams and thus to the introduction of a key feature of plasmas near phase transitions, namely, long-range correlations. After fixing the model parameters using input from LQCD for the crossover transition at vanishing chemical potential, we study the location of the Critical End Point in the effective QCD phase diagram. We use the model to study baryon number fluctuations and show that in heavy-ion collisions, the CEP can be located for collision energies $\sqrt{s_{NN}}\sim 2$ GeV, namely, in the lowest NICA or within the HADES energy domain.

   hep-phhep-thnucl-thEPJA(2022)·14 citations
6. 06*

   The $R^2$-Higgs inflation with two Higgs doublets

   Sung Mook Lee🇰🇷 · Tanmoy Modak🇩🇪 · Kin-ya Oda🇯🇵 · Tomo Takahashi🇯🇵

   We study $R^2$-Higgs inflation in a model with two Higgs doublets in which the Higgs sector of the Standard Model is extended by an additional Higgs doublet, thereby four scalar fields are involved in the inflationary evolutions. We first derive the set of equations required to follow the inflationary dynamics in this two Higgs doublet model, allowing a nonminimal coupling between the Higgs-squared and the Ricci scalar $R$, as well as the $R^2$ term in the covariant formalism. By numerically solving the system of equations, we find that, in parameter space where a successful $R^2$-Higgs inflation are realized and consistent with low energy constraints, the inflationary dynamics can be effectively described by a single slow-roll formalism even though four fields are involved in the model. We also argue that the parameter space favored by $R^2$-Higgs inflation requires nearly degenerate masses for $m_{\mathsf{H}}$, $m_A$ and $m_{{\mathsf{H}}^{\pm }}$, where $\mathsf{H}$, $A$, and ${\mathsf{H}}^{\pm }$ are the extra CP even, CP odd, and charged Higgs bosons in the general two Higgs doublet model taking renormalization group evolutions of the parameters into account. Discovery of such heavy scalars at the Large Hadron Collider (LHC) are possible if they are in the sub-TeV mass range. Indirect evidences may also emerge at the LHCb and Belle-II experiments, however, to probe the quasi degenerate mass spectra one would likely require high luminosity LHC or future lepton colliders such as the International Linear Collider and the Future Circular Collider.

   hep-phastro-ph.COhep-exEPJC(2022)·13 citations
7. 07*

   X_1(2900) as a D_1 K molecule

   Hao Chen🇨🇳 · Hong-Rong Qi🇨🇳 · Han-Qing Zheng🇨🇳

   The analyses of the LHCb data on X(2900) in the D^- K^+ spectrum are performed. Both dynamically generated and explicitly introduced X_1(2900) are considered. The results show that both these two approaches support the interpretation of X_1(2900) as a bar{D}_1 K molecular state, with J^{P}=1^- and an iso-singlet interpretation is much more favorable. The effect of triangle singularity on the production of X_1(2900) is also discussed, and it is found that it cannot be interpreted as a pure triangle cusp.

   hep-phEPJC(2021)·28 citations
8. 08*

   Improved Treatment of Dark Matter Capture in Neutron Stars III: Nucleon and Exotic Targets

   Filippo Anzuini🇦🇺 · Nicole F. Bell🇦🇺 · Giorgio Busoni🇩🇪 · Theo F. Motta🇦🇺 · Sandra Robles🇦🇺 · Anthony W. Thomas🇦🇺 · Michael Virgato🇦🇺

   We consider the capture of dark matter (DM) in neutron stars via scattering on hadronic targets, including neutrons, protons and hyperons. We extend previous analyses by including momentum dependent form factors, which account for hadronic structure, and incorporating the effect of baryon strong interactions in the dense neutron star interior, rather than modelling the baryons as a free Fermi gas. The combination of these effects suppresses the DM capture rate over a wide mass range, thus increasing the cross section for which the capture rate saturates the geometric limit. In addition, variation in the capture rate associated with the choice of neutron star equation of state is reduced. For proton targets, the use of the interacting baryon approach to obtain the correct Fermi energy is essential for an accurate evaluation of the capture rate in the Pauli-blocked regime. For heavy neutron stars, which are expected to contain exotic matter, we identify cases where DM scattering on hyperons contributes significantly to the total capture rate. Despite smaller neutron star capture rates, compared to existing analyses, we find that the projected DM-nucleon scattering sensitivity greatly exceeds that of nuclear recoil experiments for a wide DM mass range.

   hep-phastro-ph.COastro-ph.HEJCAP(2021)·67 citations
9. 09*

   Light inflaton model in a metastable Universe

   Fedor Bezrukov🇬🇧 · Abigail Keats🇬🇧

   We minimally extend the SM with a Z${}_2$ symmetric potential containing a single scalar field, serving as our inflaton with a quartic self-coupling. In the model we have symmetry breaking in both sectors, and with the addition of an inflaton-Higgs portal, the Universe is able to efficiently reheat via 2-2 inflaton-Higgs scattering. Assuming that the Universe with a positive cosmological constant should be metastable, only one particular symmetry breaking pattern in the vacuum is possible, without the need to finely-tune the Higgs' quartic self-coupling. Inflaton with masses in the range $O(10^{-3})\le m_{\chi }\le m_h$ and mixing angles that span ${\theta }_m^2=O(10^{-11}-10^{-2})$ evade all current cosmological, experimental and stability constraints required for a metastable EW vacuum. Upgraded particle physics experiments may be able to probe the parameter space with ${\theta }_m^2\ge O(10^{-4})$, where we would observe trilinear Higgs couplings suppressed by up to $2\%$ compared to the SM value. However to access the parameter space of very weakly-coupled inflaton, we rely on the proposals to build experiments that target the hidden sector.

   hep-phPRD(2021)·3 citations
10. 10*

    A survey of heavy-heavy hadronic molecules

    Xiang-Kun Dong🇨🇳 · Feng-Kun Guo🇨🇳 · Bing-Song Zou🇨🇳

    The spectrum of hadronic molecules composed of heavy-antiheavy charmed hadrons has been obtained in our previous work. The potentials are constants at the leading order, which are estimated from resonance saturation. The experimental candidates of hadronic molecules, say $X(3872)$, $Y(4260)$, three $P_c$ states and $P_{cs}(4459)$, fit the spectrum well. The success in describing the pattern of heavy-antiheavy hadronic molecules stimulates us to give more predictions for the heavy-heavy cases, which are less discussed in literature than the heavy-antiheavy ones. Given that the heavy-antiheavy hadronic molecules, several of which have strong experimental evidence, emerge from the dominant constant interaction from resonance saturation, we find that the existence of many heavy-heavy hadronic molecules is natural. Among these predicted heavy-heavy states we highlight the $D{D}^{\ast }$ molecule and the $D^{(\ast )}{\Sigma }_c^{(\ast )}$ molecules, which are the partners of the famous $X(3872)$ and $P_c$ states. Quite recently, LHCb collaboration reported a doubly charmed tetraquark state, $T_{cc}$, which is in line with our results for the $D{D}^{\ast }$ molecule. With the first experimental signal of this new kind of exotic states, the upcoming 3pdate of the LHCb experiment as well as other experiments will provide more chances of observing the heavy-heavy hadronic molecules.

    hep-phhep-exhep-latCommun.Theor.Phys.(2021)·258 citations
11. 11*

    On Stringy Origin of Minimal Flavor Violation

    Tatsuo Kobayashi🇯🇵 · Hajime Otsuka🇯🇵

    We study the minimal flavor violation in the context of string effective field theory. Stringy selection rules indicate that $n$-point couplings among fermionic zero-modes and lightest scalar modes in the string effective action are given by a product of Yukawa couplings which are regarded as spurion fields of stringy and geometrical symmetries. Hence, Yukawa couplings determine the dynamics of flavor and CP violations. This observation strongly supports the hypothesis of minimal flavor violation in the Standard Model effective field theory.

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

    Triple nuclear collisions - a new method to explore the matter properties under new extreme conditions

    O. V. Vitiuk🇺🇦 · V. M. Pugatch🇺🇦 · K.A. Bugaev🇺🇦 · P. P. Panasiuk🇺🇦 · N. S. Yakovenko🇺🇦 · B. E. Grinyuk🇺🇦 · E. S. Zherebtsova🇷🇺 · M. Bleicher🇩🇪 · L.V. Bravina🇳🇴 · A.V. Taranenko🇷🇺 · E.E. Zabrodin🇳🇴

    We suggest to explore an entirely new method to experimentally and theoretically study the phase diagram of strongly interacting matter based on the triple nuclear collisions (TNC). We simulated the TNC using the UrQMD 3.4 model at the beam center-of-mass collision energies $\sqrt{s_{NN}}=200$ GeV and $\sqrt{s_{NN}}=2.76$ TeV. It is found that in the most central and simultaneous TNC the initial baryonic charge density is about 3 times higher than the one achieved in the usual binary nuclear collisions at the same energies. As a consequence, the production of protons and $\Lambda$-hyperons is increased by a factor of 2 and 1.5, respectively. Using the MIT Bag model equation we study the evolution of the central cell in TNC and demonstrate that for the top RHIC energy of collision the baryonic chemical potential is 2-2.5 times larger than the one achieved in the binary nuclear collision at the same type of reaction. Based on these estimates, we show that TNC offers an entirely new possibility to study the QCD phase diagram at very high baryonic charge densities.

    hep-phnucl-thEPJ Web Conf.(2022)·1 citation
13. 13*

    $D^0{D}^0{\pi }^{+}$ mass distribution in the production of the $T_{cc}$ exotic state

    A. Feijoo🇪🇸 · W. H. Liang🇨🇳 · E. Oset🇪🇸

    We perform a unitary coupled channel study of the interaction of the $D^{\ast +}{D}^0,D^{\ast 0}{D}^{+}$ channels and find a state barely bound, very close to isospin $I=0$. We take the experimental mass as input and obtain the width of the state and the $D^0{D}^0{\pi }^{+}$ mass distribution. When the mass of the $T_{cc}$ state quoted in the experimental paper from raw data is used, the width obtained is of the order of the $80\mathrm{keV}$, small compared to the value given in that work. Yet, when the mass obtained in an analysis of the data considering the experimental resolution is taken, the width obtained is about $43\mathrm{keV}$ and both the width and the $D^0{D}^0{\pi }^{+}$ mass distribution are in remarkable agreement with the results obtained in that latter analysis.

    hep-phPRD(2021)·139 citations
14. 14*

    Strangeness content of the pion in the U(3) Nambu-Jona-Lasinio model

    Fabio L Braghin🇧🇷

    The Nambu-Jona-Lasinio model is considered with flavor-dependent coupling constants $G_{ij}\left[(\bar{\psi }{\lambda }_i\psi )(\bar{\psi }{\lambda }_j\psi )+(\bar{\psi }i{\gamma }_5{\lambda }_i\psi )(\bar{\psi }i{\gamma }_5{\lambda }_j\psi )\right]$ for $i,j=0,\mathrm{1..}{N}_f^2-1$, and $N_f=3$. A self consistent calculation of quark effective masses and coupling constants is performed making the strange quark effective mass to vary considerably. Quantum mechanical mixings between up, down and strange constituent quarks yields a strangeness content of the light u and d quarks constituent and of the pion. Different types of estimates for the strangeness contribution for the pion mass are provided. Mixing type interactions, $G_{i\ne j}$, induce the light mesons mixings and estimates for the ${\pi }^0-\eta$ and $\eta -{\eta }^{\prime }$ mixings are provided. The $\eta -{\pi }^0$ mixing is argued to be an indication of the strangeness content of the pion.

    hep-phnucl-thJ.Phys.G(2022)·14 citations
15. 15*

    Grooming at the Cusp: All-Orders Predictions for the Transition Region of Jet Groomers

    Kees Benkendorfer🇺🇸 · Andrew J. Larkoski🇺🇸

    Jet grooming has emerged as a necessary and vital tool for mitigating contamination radiation in jets. The additional restrictions on emissions imposed by the groomer can result in non-smooth behavior of resulting fixed-order distributions of observables measured on groomed jets. As a concrete example, we study the cusp in the hemisphere mass distribution of $e^{+}{e}^{-}\to$ hadrons events groomed with soft drop. We identify the leading emissions that contribute in the region about the cusp and formulate an all-orders factorization theorem that describes how the cusp is resolved through arbitrary strongly-ordered soft and collinear emissions. The factorization theorem exhibits numerous novel features such as contributions from collinear modes that can cross hemisphere boundaries as well as requiring explicit subtraction of the limit in which resolved emissions become collinear to the hard core. We present resummation of the cusp region through next-to-leading logarithmic accuracy and describe how it can be matched with established factorization theorems that describe other groomed phase space regions.

    hep-phhep-exJHEP(2021)·13 citations
16. 16*

    Cosmologically Degenerate Fermions

    Marcela Carena🇺🇸 · Nina M. Coyle🇺🇸 · Ying-Ying Li🇺🇸 · Samuel D. McDermott🇺🇸 · Yuhsin Tsai🇺🇸

    Dark matter (DM) with a mass below a few keV must have a phase space distribution that differs substantially from the Standard Model particle thermal phase space: otherwise, it will free stream out of cosmic structures as they form. We observe that fermionic DM psi in this mass range will have a non-negligible momentum in the early Universe, even in the total absence of thermal kinetic energy. This is because the fermions were inevitably more dense at higher redshifts, and thus experienced Pauli degeneracy pressure. They fill up the lowest-momentum states, such that a typical fermion gains a momentum ~ O(p_F) that can exceed its mass m_psi. We find a simple relation between m_psi, the current fraction f_psi of the cold DM energy density in light fermions, and the redshift at which they were relativistic. Considering the impacts of the transition between nonrelativistic and relativistic behavior as revealed by measurements of DNeff and the matter power spectrum, we derive qualitatively new bounds in the f_psi-m_psi plane. We also improve existing bounds for f_psi = 1 by an order of magnitude to m_psi=2 keV. We remark on implications for direct detection and suggest models of dark sectors that may give rise to cosmologically degenerate fermions.

    hep-phastro-ph.COastro-ph.GAastro-ph.HEPRD(2022)·19 citations
17. 17*

    Exploring the phenomenology of weak adjoint scalars in minimal $R$-symmetric models

    Linda M. Carpenter🇺🇸 · Matthew J. Smylie🇺🇸

    We examine the phenomenology of the scalar fields in weak and Higgs sectors of minimal $R$-symmetric models, in particular the 'swino' and 'sbino', the scalar partners to the chiral fields that marry the electroweak gauge bosons in Dirac gaugino models. These fields are in adjoint representations of $SU(2)$ and $U(1)$ and have both $CP$-even and $CP$-odd components. The interactions of these new states are summarized, and decay widths are computed analytically to one loop order. We discuss the tree level contributions of these new states to the mass spectrum of MSSM sfermions. We also explore production cross sections and decay signatures at colliders for several chosen benchmarks. We find that large regions of parameter space are unconstrained by present collider data.

    hep-phJHEP(2022)·8 citations
18. 18*

    Covariant Color-Kinematics Duality

    Clifford Cheung🇺🇸 · James Mangan🇺🇸

    We show that color-kinematics duality is a manifest property of the equations of motion governing currents and field strengths. For the nonlinear sigma model (NLSM), this insight enables an implementation of the double copy at the level of fields, as well as an explicit construction of the kinematic algebra and associated kinematic current. As a byproduct, we also derive new formulations of the special Galileon (SG) and Born-Infeld (BI) theory. For Yang-Mills (YM) theory, this same approach reveals a novel structure -- covariant color-kinematics duality -- whose only difference from the conventional duality is that $1/\square$ is replaced with covariant $1/D^2$. Remarkably, this structure implies that YM theory is itself the covariant double copy of gauged biadjoint scalar (GBAS) theory and an $F^3$ theory of field strengths encoding a corresponding kinematic algebra and current. Directly applying the double copy to equations of motion, we derive general relativity (GR) from the product of Einstein-YM and $F^3$ theory. This exercise reveals a trivial variant of the classical double copy that recasts any solution of GR as a solution of YM theory in a curved background. Covariant color-kinematics duality also implies a new decomposition of tree-level amplitudes in YM theory into those of GBAS theory. Using this representation we derive a closed-form, analytic expression for all BCJ numerators in YM theory and the NLSM for any number of particles in any spacetime dimension. By virtue of the double copy, this constitutes an explicit formula for all tree-level scattering amplitudes in YM, GR, NLSM, SG, and BI.

    ↳ hep-thhep-phJHEP(2021)·97 citations
19. 19*

    Prospective Sensitivities of Atom Interferometers to Gravitational Waves and Ultralight Dark Matter

    Leonardo Badurina🇬🇧 · Oliver Buchmueller🇬🇧 · John Ellis🇬🇧 · Marek Lewicki🇵🇱 · Christopher McCabe🇬🇧 · Ville Vaskonen🇪🇸

    We survey the prospective sensitivities of terrestrial and space-borne atom interferometers (AIs) to gravitational waves (GWs) generated by cosmological and astrophysical sources, and to ultralight dark matter. We discuss the backgrounds from gravitational gradient noise (GGN) in terrestrial detectors, and also binary pulsar and asteroid backgrounds in space-borne detectors. We compare the sensitivities of LIGO and LISA with those of the 100m and 1km stages of the AION terrestrial AI project, as well as two options for the proposed AEDGE AI space mission with cold atom clouds either inside or outside the spacecraft, considering as possible sources the mergers of black holes and neutron stars, supernovae, phase transitions in the early Universe, cosmic strings and quantum fluctuations in the early Universe that could have generated primordial black holes. We also review the capabilities of AION and AEDGE for detecting coherent waves of ultralight scalar dark matter.

    ↳ gr-qcastro-ph.HEhep-exhep-phPhil.Trans.Roy.Soc.Lond.A(2022)·120 citations
20. 20*

    Numerical fluid dynamics for FRG flow equations: Zero-dimensional QFTs as numerical test cases. I. The $O(N)$ model

    Adrian Koenigstein🇩🇪 · Martin J. Steil🇩🇪 · Nicolas Wink🇩🇪 · Eduardo Grossi🇺🇸 · Jens Braun🇩🇪 · Michael Buballa🇩🇪 · Dirk H. Rischke🇩🇪

    The functional renormalization group (FRG) approach is a powerful tool for studies of a large variety of systems, ranging from statistical physics over the theory of the strong interaction to gravity. The practical application of this approach relies on the derivation of so-called flow equations, which describe the change of the quantum effective action under the variation of a coarse-graining parameter. In the present work, we discuss in detail a novel approach to solve such flow equations. This approach relies on the fact that RG equations can be rewritten such that they exhibit similarities with the conservation laws of fluid dynamics. This observation can be exploited in different ways. First of all, we show that this allows to employ powerful numerical techniques developed in the context of fluid dynamics to solve RG equations. In particular, it allows us to reliably treat the emergence of nonanalytic behavior in the RG flow of the effective action as it is expected to occur in studies of, e.g., spontaneous symmetry breaking. Second, the analogy between RG equations and fluid dynamics offers the opportunity to gain novel insights into RG flows and their interpretation in general, including the irreversibility of RG flows. We work out this connection in practice by applying it to zero-dimensional quantum-field theoretical models. The generalization to higher-dimensional models is also discussed. Our findings are expected to help improving future FRG studies of quantum field theories in higher dimensions both on a qualitative and quantitative level.

    ↳ cond-mat.stat-mechhep-phphysics.comp-phphysics.flu-dynPRD(2022)·66 citations
21. 21*

    Resurgence and $1/N$ Expansion in Integrable Field Theories

    Lorenzo Di Pietro🇮🇹 · Marcos Mariño🇨🇭 · Giacomo Sberveglieri🇮🇹 · Marco Serone🇮🇹

    In theories with renormalons the perturbative series is factorially divergent even after restricting to a given order in $1/N$, making the $1/N$ expansion a natural testing ground for the theory of resurgence. We study in detail the interplay between resurgent properties and the $1/N$ expansion in various integrable field theories with renormalons. We focus on the free energy in the presence of a chemical potential coupled to a conserved charge, which can be computed exactly with the thermodynamic Bethe ansatz (TBA). In some examples, like the first $1/N$ correction to the free energy in the non-linear sigma model, the terms in the $1/N$ expansion can be fully decoded in terms of a resurgent trans-series in the coupling constant. In the principal chiral field we find a new, explicit solution for the large $N$ free energy which can be written as the median resummation of a trans-series with infinitely many, analytically computable IR renormalon corrections. However, in other examples, like the Gross-Neveu model, each term in the $1/N$ expansion includes non-perturbative corrections which can not be predicted by a resurgent analysis of the corresponding perturbative series. We also study the properties of the series in $1/N$. In the Gross-Neveu model, where this is convergent, we analytically continue the series beyond its radius of convergence and show how the continuation matches with known dualities with sine-Gordon theories.

    ↳ hep-thhep-lathep-phmath-ph+1JHEP(2021)·58 citations
22. 22*

    Two-particle scattering from finite-volume quantization conditions using the plane wave basis

    Lu Meng🇩🇪 · E. Epelbaum🇩🇪

    We propose an alternative approach to Lüscher's formula for extracting two-body scattering phase shifts from finite volume spectra with no reliance on the partial wave expansion. We use an effective-field-theory-based Hamiltonian method in the plane wave basis and decompose the corresponding matrix elements of operators into irreducible representations of the relevant point groups. The proposed approach allows one to benefit from the knowledge of the long-range interaction and avoids complications from partial wave mixing in a finite volume. We consider spin-singlet channels in the two-nucleon system and pion-pion scattering in the $\rho$-meson channel in the rest and moving frames to illustrate the method for non-relativistic and relativistic systems, respectively. For the two-nucleon system, the long-range interaction due to the one-pion exchange is found to make the single-channel Lüscher formula unreliable at the physical pion mass. For S-wave dominated states, the single-channel Lüscher method suffers from significant finite-volume artifacts for a $L=3$~fm box, but it works well for boxes with $L>5$~fm. However, for P-wave dominated states, significant partial wave mixing effects prevent the application of the single-channel Lüscher formula regardless of the box size (except for the near-threshold region). Using a toy model to generate synthetic data for finite-volume energies, we show that our effective-field-theory-based approach in the plane wave basis is capable of a reliable extraction of the phase shifts. For pion-pion scattering, we employ a phenomenological model to fit lattice QCD results at the physical pion mass. The extracted P-wave phase shifts are found to be in a good agreement with the experimental results.

    ↳ hep-lathep-phnucl-thJHEP(2021)·46 citations
23. 23*

    Physics Beyond the Standard Model with BlackHawk v2.0

    Alexandre Arbey🇫🇷 · Jérémy Auffinger🇫🇷

    We present the new version v2.0 of the public code BlackHawk designed to compute the Hawking radiation of black holes, with both primary and hadronized spectra. This new version aims at opening an avenue toward physics beyond the Standard Model (BSM) in Hawking radiation. Several major additions have been made since version v1.0: dark matter/dark radiation emission, spin $3/2$ greybody factors, scripts for cosmological studies, BSM black hole metrics with their associated greybody factors and a careful treatment of the low energy showering of secondary particles; as well as bug corrections. We present, in each case, examples of the new capabilities of BlackHawk.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph+1EPJC(2021)·152 citations
24. 24*

    Small-scale clumping at recombination and the Hubble tension

    Michael Rashkovetskyi · Julian B. Muñoz🇺🇸 · Daniel J. Eisenstein · Cora Dvorkin🇺🇸

    Despite the success of the standard $\Lambda$CDM model of cosmology, recent data improvements have made tensions emerge between low- and high-redshift observables, most importantly in determinations of the Hubble constant $H_0$ and the (rescaled) clustering amplitude $S_8$. The high-redshift data, from the cosmic microwave background (CMB), crucially relies on recombination physics for its interpretation. Here we study how small-scale baryon inhomogeneities (i.e., clumping) can affect recombination and consider whether they can relieve both the $H_0$ and $S_8$ tensions. Such small-scale clumping, which may be caused by primordial magnetic fields or baryon isocurvature below kpc scales, enhances the recombination rate even when averaged over larger scales, shifting recombination to earlier times. We introduce a flexible clumping model, parametrized via three spatial zones with free densities and volume fractions, and use it to study the impact of clumping on CMB observables. We find that increasing $H_0$ decreases both ${\Omega }_m$ and $S_8$, which alleviates the $S_8$ tension. On the other hand, the shift in ${\Omega }_m$ is disfavored by the low-$z$ baryon-acoustic-oscillations measurements. We find that the clumping parameters that can change the CMB sound horizon enough to explain the $H_0$ tension also alter the damping tail, so they are disfavored by current Planck 2018 data. We test how the CMB damping-tail information rules out changes to recombination by first removing $\ell >1000$ multipoles in Planck data, where we find that clumping could resolve the $H_0$ tension. Furthermore, we make predictions for future CMB experiments, as their improved damping-tail precision can better constrain departures from standard recombination. Both the Simons Observatory and CMB-S4 will provide decisive evidence for or against clumping as a resolution to the $H_0$ tension.

    ↳ astro-ph.COhep-phPRD(2021)·48 citations
25. 25*

    Quasinormal modes of a semi-holographic black brane and thermalization

    Sukrut Mondkar🇮🇳 · Ayan Mukhopadhyay🇮🇳 · Anton Rebhan🇦🇹 · Alexander Soloviev🇺🇸

    We study the quasinormal modes and non-linear dynamics of a simplified model of semi-holography, which consistently integrates mutually interacting perturbative and strongly coupled holographic degrees of freedom such that the full system has a total conserved energy. We show that the thermalization of the full system can be parametrically slow when the mutual coupling is weak. For typical homogeneous initial states, we find that initially energy is transferred from the black brane to the perturbative sector, later giving way to complete transfer of energy to the black brane at a slow and constant rate, while the entropy grows monotonically for all time. Larger mutual coupling between the two sectors leads to larger extraction of energy from the black brane by the boundary perturbative system, but also quicker irreversible transfer of energy back to the black brane. The quasinormal modes replicate features of a dissipative system with a softly broken symmetry including the so-called k-gap. Furthermore, when the mutual coupling is below a critical value, there exists a hybrid zero mode with finite momentum which becomes unstable at higher values of momentum, indicating a Gregory-Laflamme type instability. This could imply turbulent equipartitioning of energy between the boundary and the holographic degrees of freedom in the presence of inhomogeneities.

    ↳ hep-thgr-qchep-phJHEP(2021)·13 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.