Mon·Jun 12, 2023Monday·June 12, 2023

1. 01*

   Double particle production in ultraperipheral $PbPb$ collisions at the Large Hadron Collider and Future Circular Collider

   Celsina N. Azevedo🇧🇷 · Victor P. Goncalves🇧🇷 · Bruno D. Moreira🇧🇷

   In this paper we analyze the associated production of a vector meson with a (pseudo)scalar bound state or a dimuon system in ultraperipheral $PbPb$ collisions through the double scattering mechanism for the energies of the Large Hadron Collider (LHC) and Future Circular Collider (FCC). Our results complement previous studies for the double vector meson production. We present our predictions for the total cross sections and rapidity distributions considering the rapidity ranges covered by the ALICE and LHCb detectors, which indicate that a future experimental analysis of the $\varphi +{\eta }_c$, $\varphi +{\mu }^{+}{\mu }^{-}$ and $J/\Psi +{\mu }^{+}{\mu }^{-}$ final states is feasible.

   hep-phnucl-thEPJA(2023)·6 citations
2. 02*

   SMEFT probes in future precision DIS experiments

   Chiara Bissolotti🇺🇸 · Radja Boughezal🇺🇸 · Kaan Simsek🇺🇸

   We analyze the potential of future high-energy deep-inelastic scattering (DIS) experiments to probe new physics within the framework of the Standard Model Effective Field Theory (SMEFT). We perform a detailed study of SMEFT probes at a future Large Hadron-electron Collider (LHeC) and a Future Circular lepton-hadron Collider (FCC-eh) machine, and extend previous simulations of the potential of a Electron-Ion Collider (EIC) to include Z-boson vertex corrections. Precision Z-pole constraints on vertex corrections suffer from numerous degeneracies in the Wilson-coefficient parameter space. We find that both the LHeC and the FCC-eh can help remove these degeneracies present in the existing global fits of precision Z-pole observables and LHC data. The FCC-eh and LHeC will in many cases improve upon the existing precision electroweak bounds on the SMEFT parameter space. This highlights the important role of precision DIS measurements for new physics studies.

   hep-phPRD(2023)·15 citations
3. 03*

   The $\Lambda$-type P-wave bottom baryon states via the QCD sum rules

   Qi Xin🇨🇳 · Zhi-Gang Wang🇨🇳 · Fei Lu🇨🇳

   Our study focuses on the $\Lambda$-type P-wave bottom baryon states with the spin-parity $J^P={\frac{1}{2}}^{-}$, ${\frac{3}{2}}^{-}$. We introduce an explicit P-wave between the two light quarks in the interpolating currents (and the two light quarks are antisymmetric in flavor space, therefore leads to the name $\Lambda$-type baryon) to investigate the ${\Lambda }_b$ and ${\Xi }_b$ states within the framework of the full QCD sum rules. The predicted masses show that the ${\Xi }_b(6087)$ and ${\Xi }_b(6095/6100)$ could to be the P-wave bottom-strange baryon states with the spin-parity $J^P={\frac{1}{2}}^{-}$ and ${\frac{3}{2}}^{-}$, respectively, meanwhile, the ${\Lambda }_b(5912)$ and ${\Lambda }_b(5920)$ could be the P-wave bottom baryon states with the spin-parity $J^P={\frac{1}{2}}^{-}$ and ${\frac{3}{2}}^{-}$, respectively. The ${\Lambda }_b(5920)$ and ${\Xi }_b(6095/6100)$ maybe have two remarkable under-structures or Fock components at least.

   hep-phCPC(2023)·10 citations
4. 04*

   Hadronic Light by Light Corrections to the Muon Anomalous Magnetic Moment

   Daniel Melo-Porras🇨🇱 · Edilson Alfonso Reyes Rojas🇨🇴 · Angelo Raffaele Fazio🇨🇴

   We review the Hadronic Light-by-Light (HLbL) contribution to the muon anomalous magnetic moment. Upcoming measurements will reduce the experimental uncertainty of this precision observable by a factor of four, thus breaking the current balance with the theoretical prediction. A necessary step to restore it is to decrease the HLbL contribution error, which implies a study of the high-energy intermediate states that are neglected in dispersive estimates. We focus on the maximally symmetric high-energy regime and in quark loop approximation of perturbation theory we check the kinematic-singularity/zero-free tensor decomposition of the HLbL amplitude.

   hep-phParticles(2024)·2 citations
5. 05*

   $A_4$ Modular Flavour Model of Quark Mass Hierarchies close to the Fixed Point $\tau =i\infty$

   S. T. Petcov🇮🇹 · M. Tanimoto🇯🇵

   We study the possibility to generate the quark mass hierarchies as well as the CKM quark mixing and CP violation without fine-tuning in a quark flavour model with modular $A_4$ symmetry. The quark mass hierarchies are considered in the vicinity of the fixed point $\tau =i\infty$, $\tau$ being the vacuum expectation value of the modulus. We consider first a model in which the up-type and down-type quark mass matrices $M_u$ and $M_d$ involve modular forms of level 3 and weights 6, 4 and 2 and each depends on four constant parameters. We also consider the case of $M_u$ and $M_d$ depending on the same $\tau$ and involving modular forms of weights 8, 4, 2 and 6, 4, 2, respectively, with $M_u$ receiving a tiny SUSY breaking or higher dimensional operator contribution. Both the mass hierarchies of up-type and down-type quarks as well and the CKM mixing angles and CP violating phase are reproduced successfully with one complex parameter and all parameters being in magnitude of the same order. The relatively large value of $\mathrm{Im}\tau$, needed for describing the down-type quark mass hierarchies, is crucial for obtaining the correct up-type quark mass hierarchies.

   hep-phJHEP(2023)·51 citations
6. 06*

   Supersymmetry : A decade after Higgs discovery

   V. Suryanarayana Mummidi🇮🇳 · Priyanka Lamba🇵🇱 · Sudhir K. Vempati🇮🇳

   Supersymmetric extensions of the Standard Model have been in vogue for over half a century. They have many interesting theoretical properties like calculability, absence of quadratic divergences, and phenomenologically impactful features like gauge coupling unification, dark matter candidates, signatures at present and future colliders, etc. A defining feature of these models is the calculability of Higgs mass in terms of a few parameters. The discovery of a Higgs particle with a mass of around 125 GeV thus has significant implications. The null results for the searches of superpartners at LHC has also put further constraints. Taken together with direct detection limits on WIMP (Weakly Interacting Massive Particle) dark matter, it appears that TeV scale supersymmetry is not realised in Nature and the theoretical expectations have reached a turning point. The present onslaught from the experiments suggests that supersymmetric models need a more complex particle structure, lagrangian and breaking patterns to be a natural solution to the hierarchy problem. We review existing models and discuss their feasibility in the current and future experimental programs.

   hep-phhep-thIndian J.Phys.(2023)·2 citations
7. 07*

   Event-shape-dependent analysis of charm-anticharm azimuthal correlations in simulations

   Aniko Horvath🇭🇺 · Eszter Frajna🇭🇺 · Robert Vertesi🇭🇺

   In high-energy collisions of small systems, by high-enough final-state multiplicities, a collective behaviour is present that is similar to the flow patterns observed in heavy-ion collisions. Recent studies connect this collectivity to semi-soft vacuum-QCD processes. Here we explore QCD production mechanisms using angular correlations of heavy flavour using simulated proton-proton collisions at $\sqrt{s}=13$~TeV with the PYTHIA8 Monte Carlo event generator. We demonstrate that the event shape is strongly connected to the production mechanisms. Flattenicity, a novel event descriptor, can be used to separate events containing the final-state radiation from the rest of the events.

   hep-phUniverse(2023)·3 citations
8. 08*

   Complete EFT Operator Bases for Dark Matter and Weakly-Interacting Light Particle

   Huayang Song🇨🇳 · Hao Sun🇨🇳 · Jiang-Hao Yu🇨🇳

   The standard model can be extended to include weakly-interacting light particle (WILP): real or complex singlet scalar, Majorana or Dirac neutral fermion, neutral or hidden-charged vector boson, etc. Imposing the $Z_2$ symmetry, these particles can be lifted as the weakly-interacting massive particle (WIMP), the candidate of dark matter. Instead, imposing the shift symmetry on the scalar components gives rise to the axion-like particle, dark photon, etc. Utilizing these light degree of freedom along with the standard model particles and imposing different symmetries, we construct the complete and independent sets of effective operators up to dimension eight with the Young tensor technique, consistent with counting from the Hilbert series.

   hep-phJHEP(2024)·32 citations
9. 09*

   Threshold factorization of the Drell-Yan quark-gluon channel and two-loop soft function at next-to-leading power

   Alessandro Broggio🇦🇹 · Sebastian Jaskiewicz🇬🇧 · Leonardo Vernazza🇮🇹

   We present a factorization theorem of the partonic Drell-Yan off-diagonal processes $g\bar{q}(qg)\to {\gamma }^{\ast }+X$ in the kinematic threshold regime $z=Q^2/\hat{s}\to 1$ at general subleading powers in the $(1-z)$ expansion. Focusing on the first order of the expansion (next-to-leading power accuracy with respect to the leading power $q\bar{q}$ channel), we validate the bare factorization formula up to $\mathcal{O}({\alpha }_s^2)$. This is achieved by carrying out an explicit calculation of the generalized soft function in $d$-dimensions using the reduction to master integrals and the differential equations method. The collinear function is a universal object which we compute from an operator matching equation at one-loop level. Next, we integrate the soft and collinear functions over the convolution variables and remove the remaining initial state collinear singularities through PDF renormalization. The resulting expression agrees with the known cross section in the literature.

   hep-phJHEP(2023)·20 citations
10. 10*

    Testing the light scalar meson as a non-$q\bar{q}$ state in semileptonic $D$ decays

    Yu-Kuo Hsiao🇨🇳 · Shu-Qi Yang🇨🇳 · Wen-Juan Wei🇨🇳 · Bai-Cian Ke🇨🇳

    While the light scalar mesons ($S_0$) are considered to be either ordinary $q\bar{q}$ or exotic tetraquark states, we investigate the semileptonic decays $D\to S_0{e}^{+}{\nu }_e$, by taking into account the resonant effects of $S_0\to M_1{M}_2$, where $S_0=a_0(980)$, $f_0(980)$, and $f_0(500)/{\sigma }_0$, and $M_{1(2)}$ represents a pseudoscalar meson. For the first time, the $D\to S_0$ form factors in the two quark structures are both presented. Subsequently, we calculate $\mathcal{B}(D_s^{+}\to {\sigma }_0{e}^{+}{\nu }_e,{\sigma }_0\to {\pi }^{+}{\pi }^{-})=(20.3\pm 1.8\pm 0.5)\times 10^{-4}$ in the $q\bar{q}$ structure, showing significant $9\sigma$ deviations from the experimental upper limit of $3.3\times 10^{-4}$. In contrast, $\mathcal{B}(D_s^{+}\to {\sigma }_0{e}^{+}{\nu }_e,{\sigma }_0\to {\pi }^{+}{\pi }^{-})=(0.58_{-0.57}^{+1.43}\pm 0.01)\times 10^{-4}$ in the $q^2{\bar{q}}^2$ structure is within the allowed experimental range. Clearly, the light scalar meson is tested as a non-$q\bar{q}$ state. We hence demonstrate a highly sensitive new approach for exploring the true nature of scalar mesons, which can be extended to non-leptonic $D$ decays as well as $B$ meson decays.

    hep-phhep-exJHEP(2025)·22 citations
11. 11*

    FIMPzilla dark matter and conformal sectors

    Ameen Ismail🇺🇸

    We point out a dark matter candidate which arises in a minimal extension of solutions to the hierarchy problem based on compositeness. In such models, some or all of the Standard Model fields are composites of a conformal field theory (CFT) which confines near the electroweak scale. We posit an elementary scalar field, whose mass is expected to lie near the cutoff of the CFT, and whose couplings to the Standard Model are suppressed by the cutoff. Hence it can naturally be ultraheavy and feebly coupled. This scalar can constitute all of the dark matter for masses between $10^{10}$ GeV and $10^{18}$ GeV, with the relic abundance produced by the freeze-in mechanism via a coupling to the CFT. The principal experimental constraints come from bounds on the tensor-to-scalar ratio. We speculate about future detection prospects.

    hep-phPRD(2023)·2 citations
12. 12*

    Top-quark cross sections and distributions at aN${}^3$LO

    Nikolaos Kidonakis🇺🇸 · Marco Guzzi🇺🇸 · Alberto Tonero🇺🇸

    We present theoretical predictions for top-quark total cross sections and for differential distributions in top-quark transverse momentum and rapidity. Third-order soft gluon corrections are added to the complete NNLO quantities to provide approximate N${}^3$LO (aN${}^3$LO) results, and electroweak corrections at NLO are also included. We calculate the theoretical uncertainties from scale dependence and from parton distribution functions in the proton, and estimate their impact on the total and differential cross sections. The higher-order corrections are large and they reduce the scale uncertainties. The results presented in this work include the best current theoretical input and are in good agreement with recent data from the LHC.

    hep-phPRD(2023)·21 citations
13. 13*

    The Effective Field Theory of Large-Scale Structure and Multi-tracer II: redshift space and realistic tracers

    Thiago Mergulhão🇬🇧 · Henrique Rubira🇩🇪 · Rodrigo Voivodic🇧🇷

    We extend the multi-tracer (MT) formalism of the effective field theory of large-scale structure to redshift space, comparing the results of MT to a single-tracer analysis when extracting cosmological parameters from simulations. We used a sub-halo abundance matching method to obtain more realistic multi-tracer galaxy catalogs constructed from N-body simulations. Considering different values for the sample shot noise and volume, we show that the MT error bars on $A_s$, ${\omega }_{\mathrm{cdm}}$, and $h$ in a full-shape analysis are approximately $50\%$ smaller relative to ST. We find that cosmological and bias coefficients from MT are less degenerate, indicating that the MT parameter basis is more orthogonal. We conclude that using MT combined with perturbation theory is a robust and competitive way to accommodate the information present in the mildly non-linear scales.

    ↳ astro-ph.COgr-qchep-phJCAP(2024)·13 citations
14. 14*

    Chiral-even axial twist-3 GPDs of the proton from lattice QCD

    Shohini Bhattacharya🇺🇸 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Jack Dodson🇺🇸 · Andreas Metz🇺🇸 · Aurora Scapellato🇺🇸 · Fernanda Steffens🇩🇪

    This work presents the first lattice-QCD calculation of the twist-3 axial quark GPDs for the proton using the large-momentum effective theory approach. We calculate matrix elements with momentum-boosted proton states and a non-local axial operator. The calculation is performed using one ensemble of two degenerate light, a strange and a charm quark ($N_f=2+1+1$) of maximally twisted mass fermions with a clover term. The ensemble has a volume $32^3\times 64$, lattice spacing 0.0934 fm, and corresponds to a pion mass of 260 MeV. The matrix elements are calculated for three values of the proton momentum, namely 0.83, 1.25, and 1.67 GeV. The light-cone GPDs are defined in the symmetric frame, which we implement here with a (negative) 4-momentum transfer squared of 0.69, 1.38, and 2.76 GeV${}^2$, all at zero skewness. We also conduct several consistency checks, including assessing the local limit of the twist-3 GPDs and examining the Burkhardt-Cottingham-type as well as Efremov-Teryaev-Leader-type sum rules.

    ↳ hep-lathep-exhep-phnucl-thPRD(2023)·49 citations
15. 15*

    $B\to D^{\ast }\ell {\nu }_{\ell }$ semileptonic form factors from lattice QCD with Möbius domain-wall quarks

    Y. Aoki🇯🇵 · B. Colquhoun🇬🇧 · H. Fukaya🇯🇵 · S. Hashimoto🇯🇵 · T. Kaneko🇯🇵 · R. Kellermann🇯🇵 · J. Koponen🇩🇪 · E. Kou (JLQCD Collaboration)🇫🇷

    We calculate the form factors for the $B\to D^{\ast }\ell {\nu }_{\ell }$ decay in 2+1 flavor lattice QCD. For all quark flavors, we employ the Möbius domain-wall action, which preserves chiral symmetry to a good precision. Our gauge ensembles are generated at three lattice cutoffs $a^{-1}\sim 2.5$, 3.6 and 4.5 GeV with pion masses as low as $M_{\pi }\sim 230$ MeV. The physical lattice size $L$ satisfies the condition $M_{\pi }L\ge 4$ to control finite volume effects (FVEs), while we simulate a smaller size at the smallest $M_{\pi }$ to directly examine FVEs. The bottom quark masses are chosen in a range from the physical charm quark mass to $0.7a^{-1}$ to control discretization effects. We extrapolate the form factors to the continuum limit and physical quark masses based on heavy meson chiral perturbation theory at next-to-leading order. Then the recoil parameter dependence is parametrized using a model independent form leading to our estimate of the decay rate ratio between the tau ($\ell =\tau$) and light lepton ($\ell =e,\mu$) channels $R(D^{\ast })=0.252(22)$ in the Standard Model. A simultaneous fit with recent data from the Belle experiment yields $|V_{cb}|=39.19(91)\times 10^{-3}$, which is consistent with previous exclusive determinations, and shows good consistency in the kinematical distribution of the differential decay rate between the lattice and experimental data.

    ↳ hep-lathep-exhep-phPRD(2024)·107 citations
16. 16*

    A multishell solution in the Skyrme model

    V.V. Flambaum🇦🇺 · I.B. Samsonov🇦🇺

    We consider multishell configurations in the Skyrme model within the rational map ansatz. We show that equations for the Skyrme field are linearized in the limit of large number of shells, thus allowing for a simple analytic solution. Although this solution is approximate, it provides an accurate description of multishell configurations in the Skyrme model in the region where the Skyrme field is large, $F\gg 1$. We use this solution to calculate the mass and the root mean square radius of multishell skyrmion configurations. In particular, for solutions with one unit of baryon charge per shell (the ``hedgehog'' solution) the mass scales as $M\propto B^2$, and its rms radius scales as $B^{1/2}$ with the baryon charge $B$. This scaling for the mass can be reduced to $M\propto B^{4/3}$ in the model with many units of baryon charge per shell. Although this solution is unstable against decays into single-shell or single-skyrmion configurations, it may be useful for modelling skyrmion stars or compact composite objects in some models of dark matter if the decay of such configurations is prevented by some mechanism.

    ↳ hep-thhep-phPRD(2023)·2 citations
17. 17*

    Lattice calculation of the $D_s$ meson radiative form factors over the full kinematical range

    R. Frezzotti🇮🇹 · G. Gagliardi🇮🇹 · V. Lubicz🇮🇹 · G. Martinelli🇮🇹 · F. Mazzetti🇮🇹 · C. T. Sachrajda🇬🇧 · F. Sanfilippo🇮🇹 · S. Simula🇮🇹 · N. Tantalo🇮🇹

    We compute the structure-dependent axial and vector form factors for the radiative leptonic decays $D_s\to \ell {\nu }_{\ell }\gamma$, where $\ell$ is a charged lepton, as functions of the energy of the photon in the rest frame of the $D_s$ meson. The computation is performed using gauge-field configurations with 2+1+1 sea-quark flavours generated by the European Twisted Mass Collaboration and the results have been extrapolated to the continuum limit. For the vector form factor we observe a very significant partial cancellation between the contributions from the emission of the photon from the strange quark and that from the charm quark. The results for the form factors are used to test the reliability of various Anzätze based on single-pole dominance and its extensions, and we present a simple parametrization of the form factors which fits our data very well and which can be used in future phenomenological analyses. Using the form factors we compute the differential decay rate and the branching ratio for the process $D_s\to e{\nu }_e\gamma$ as a function of the lower cut-off on the photon energy. With a cut-off of 10 MeV for example, we find a branching ratio of Br$(E_{\gamma }>10\mathrm{MeV})=4.4(3)\times 10^{-6}$ which, unlike some model calculations, is consistent with the upper bound from the BESIII experiment Br$(E_{\gamma }>10\mathrm{MeV})<1.3\times 10^{-4}$ at 90% confidence level. Even for photon energies as low as 10 MeV, the decay $D_s\to e{\nu }_e\gamma$ is dominated by the structure-dependent contribution to the amplitude (unlike the decays with $\ell =\mu$ or $\tau$), confirming its value in searches for hypothetical new physics as well as in determining the Cabibbo-Kobayashi-Maskawa (CKM) parameters at $O({\alpha }_{\mathrm{em}})$, where ${\alpha }_{\mathrm{em}}$ is the fine-structure constant.

    ↳ hep-lathep-phPRD(2023)·22 citations
18. 18*

    First results from BRASS-p broadband searches for hidden photon dark matter

    Fayez Bajjali🇩🇪 · Sven Dornbusch🇩🇪 · Marko Ekmedžić🇩🇪 · Dieter Horns🇩🇪 · Christoph Kasemann🇩🇪 · Andrei Lobanov🇩🇪 · Artak Mkrtchyan🇦🇲 · Le Hoang Nguyen🇩🇪 · Martin Tluczykont🇩🇪 · Gino Tuccari🇩🇪 · Johannes Ulrichs🇩🇪 · Gundolf Wieching🇩🇪 · Anton Zensus🇩🇪

    We discuss first results from hidden photon dark matter searches made with a prototype of the Broadband Radiometric Axion/ALPs Search Setup (BRASS-p) in the range of particle mass of 49.63-74.44 $\mu$eV (frequency range of 12-18 GHz). The conceptual design of BRASS and a detailed description of its present prototype, BRASS-p, are given, with a view of the potential application of such setups to hidden photon, axion, and axion-like particle (ALP) dark matter searches using heterodyne detectors in the range of particle mass from 40$\mu$eV to 4000$\mu$eV (10 GHz to 1 THz). Pioneering measurements made with BRASS-p achieve the record sensitivity of (0.3--1.0)$\times$$10^{-13}$ to the kinetic mixing between the normal and hidden photons, assuming the dark matter is made entirely of unpolarized hidden photons. Based on these results, a discussion of further prospects for dark matter searches using the BRASS-p apparatus is presented.

    ↳ hep-exhep-phphysics.ins-detJCAP(2023)·42 citations
19. 19*

    Interplay of Chiral Transitions in the Standard Model

    Holger Gies🇩🇪 · Richard Schmieden🇩🇪 · Luca Zambelli🇮🇹

    We investigate nonperturbative aspects of the interplay of chiral transitions in the standard model in the course of the renormalization flow. We focus on the chiral symmetry breaking mechanisms provided by the QCD and the electroweak sectors, the latter of which we model by a Higgs-top-bottom Yukawa theory. The interplay becomes quantitatively accessible by accounting for the fluctuation-induced mixing of the electroweak Higgs field with the mesonic composite fields of QCD. In fact, our approach uses dynamical bosonization and treats these scalar fields on the same footing. Varying the QCD scale relative to the Fermi scale we quantify the mutual impact of the symmetry-breaking mechanisms, specifically the departure from the second order quantum phase transition of the pure Yukawa sector in favor of a crossover upon the inclusion of the gauge interactions. This allows to discuss the ``naturalness'' of the standard model in terms of a pseudo-critical exponent which we determine as a function of the ratio of the QCD and the Fermi scale. We also estimate the minimum value of the $W$ boson mass in absence of the Higgs mechanism.

    ↳ hep-thhep-phEPJC(2025)·6 citations
20. 20*

    Scattering Amplitudes in Quantum Field Theory

    Simon Badger🇮🇹 · Johannes Henn🇩🇪 · Jan Plefka🇩🇪 · Simone Zoia🇮🇹

    These lecture notes bridge a gap between introductory quantum field theory (QFT) courses and state-of-the-art research in scattering amplitudes. They cover the path from basic definitions of QFT to amplitudes relevant for processes in the Standard Model of particle physics. The book begins with a concise yet self-contained introduction into QFT, including perturbative quantum gravity. It then presents modern methods for calculating scattering amplitudes, focusing on tree-level amplitudes, loop-level integrands and loop-integration techniques. These methods help reveal intriguing relations between gauge and gravity amplitudes, and are of increasing importance for obtaining high-precision predictions for collider experiments, such as those at CERN's Large Hadron Collider, as well as for foundational mathematical physics studies in QFT, including recent applications to gravitational wave physics. These course-tested lecture notes include numerous exercises with detailed solutions. Requiring only minimal knowledge of QFT, they are well-suited for MSc and PhD students as a preparation for research projects in theoretical particle physics. They can be used as a one-semester graduate level course, or as a self-study guide for researchers interested in fundamental aspects of QFT. Supplementary material, Mathematica notebooks, corrections and further information are provided and maintained at the dedicated website https://scattering-amplitudes.mpp.mpg.de/scattering-amplitudes-in-qft/ .

    ↳ hep-thhep-phLect.Notes Phys.(2024)·81 citations
21. 21*

    Light Scalar Meson and Decay Constant in SU(3) Gauge Theory with Eight Dynamical Flavors

    Lattice Strong Dynamics Collaboration: R. C. Brower (1)🇺🇸 · E. Owen (1)🇺🇸 · C. Rebbi (1)🇺🇸 · C. Culver (2)🇬🇧 · D. Schaich (2)🇬🇧 · K. K. Cushman (3)🇺🇸 · G. T. Fleming (3 and 4)🇺🇸 · A. Gasbarro (5)🇨🇭 · A. Hasenfratz (6)🇺🇸 · E. T. Neil (6)🇺🇸 · J. Ingoldby (7)🇮🇹 · X. Y. Jin (8)🇺🇸 and 5 other authors

    The SU(3) gauge theory with $N_f=8$ nearly massless Dirac fermions has long been of theoretical and phenomenological interest due to the near-conformality arising from its proximity to the conformal window. One particularly interesting feature is the emergence of a relatively light, stable flavor-singlet scalar meson $\sigma$ $(J^{PC}=0^{++})$ in contrast to the $N_f=2$ theory QCD. In this work, we study the finite-volume dependence of the $\sigma$ meson correlation function computed in lattice gauge theory and determine the $\sigma$ meson mass and decay constant extrapolated to the infinite-volume limit. We also determine the infinite volume mass and decay constant of the flavor-nonsinglet scalar meson $a_0$.

    ↳ hep-lathep-phPRD(2024)·31 citations
22. 22*

    JAXVacua -- A Framework for Sampling String Vacua

    Abhishek Dubey🇩🇪 · Sven Krippendorf🇩🇪 · Andreas Schachner🇺🇸

    Moduli stabilisation in string compactifications with many light scalars remains a major blind-spot in the string landscape. In these regimes, analytic methods cease to work for generic choices of UV parameters which is why numerical techniques have to be exploited. In this paper, we implement algorithms based on JAX, heavily utilising automatic differentiation, just-in-time compilation and parallelisation features, to efficiently construct string vacua. This implementation provides a golden opportunity to efficiently analyse large unexplored regions of the string landscape. As a first example, we apply our techniques to the search of Type IIB flux vacua in Calabi-Yau orientifold compactifications. We argue that our methods only scale mildly with the Hodge numbers making exhaustive studies of low energy effective field theories with $\mathcal{O}(100)$ scalar fields feasible. Using small computing resources, we are able to construct $\mathcal{O}(10^6)$ flux vacua per geometry with $h^{1,2}\ge 2$, vastly out-performing previous systematic searches. In particular, we showcase the efficiency of our methods by presenting generic vacua with fluxes below the tadpole constraint set by the orientifold with up to $h^{1,2}=25$ complex structure moduli.

    ↳ hep-thhep-phJHEP(2023)·33 citations
23. 23*

    Thomson scattering: One rate to rule them all

    Kylar Greene🇺🇸 · Francis-Yan Cyr-Racine🇺🇸

    The enduring tension between local and distant measurements of $H_0$ remains unresolved. It was recently pointed out that cosmic microwave background (CMB) and large-scale structure (LSS) observables are invariant under a uniform rescaling of the gravitational free-fall rates of all species present and the Thomson scattering rate between photons and electrons. We show that a unique variation of the fine-structure constant $\alpha$ and the electron mass $m_{\mathrm{e}}$ can leverage this scaling transformation to reconcile the CMB and LSS data with a broad spectrum of Hubble constant values, encompassing those inferred from local measurements. Importantly, this study demonstrates that the constraints on the variation of fundamental constants imposed by the specific recombination history are not as stringent as previously assumed. Our work highlights the critical role of the Thomson scattering rate in the existing Hubble tension and offers a distinct avenue of exploration for particle model builders.

    ↳ astro-ph.COhep-phJCAP(2023)·21 citations
24. 24*

    Analytic description of monodromy oscillons

    D. G. Levkov🇷🇺 · V. E. Maslov🇷🇺

    We develop precise analytic description of oscillons - long-lived quasiperiodic field lumps - in scalar field theories with nearly quadratic potentials, e.g. the monodromy potential. Such oscillons are essentially nonperturbative due to large amplitudes, and they achieve extreme longevities. Our method is based on a consistent expansion in the anharmonicity of the potential at strong fields, which is made accurate by introducing a field-dependent "running mass." At every order, we compute effective action for the oscillon profile and other parameters. Comparison with explicit numerical simulations in (3+1)-dimensional monodromy model shows that our method is significantly more precise than other analytic approaches.

    ↳ hep-thastro-ph.COhep-phPRD(2023)·9 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.