Mon·Jun 20, 2022Monday·June 20, 2022

1. 01*

   Quantum Anomaly Detection for Collider Physics

   Sulaiman Alvi🇺🇸 · Christian Bauer🇺🇸 · Benjamin Nachman🇺🇸

   Quantum Machine Learning (QML) is an exciting tool that has received significant recent attention due in part to advances in quantum computing hardware. While there is currently no formal guarantee that QML is superior to classical ML for relevant problems, there have been many claims of an empirical advantage with high energy physics datasets. These studies typically do not claim an exponential speedup in training, but instead usually focus on an improved performance with limited training data. We explore an analysis that is characterized by a low statistics dataset. In particular, we study an anomaly detection task in the four-lepton final state at the Large Hadron Collider that is limited by a small dataset. We explore the application of QML in a semi-supervised mode to look for new physics without specifying a particular signal model hypothesis. We find no evidence that QML provides any advantage over classical ML. It could be that a case where QML is superior to classical ML for collider physics will be established in the future, but for now, classical ML is a powerful tool that will continue to expand the science of the LHC and beyond.

   hep-phhep-exphysics.data-anquant-phJHEP(2023)·40 citations
2. 02*

   Magic square and three-zero textures for Dirac neutrinos

   Ryota Minamizawa🇯🇵 · Yuta Hyodo🇯🇵 · Teruyuki Kitabayashi🇯🇵

   We show a matrix decomposition of flavor mass matrix for Dirac neutrinos $M$ by sum as $M=M^{\prime }+M^0$ where $M^{\prime }$ obeys the feature of the magic square and $M^0$ is three-zero texture. The favorable three-zero textures in the context of magic square are explored. It turned out that so-called the normal ordering of neutrino masses is favored over the inverted ordering in the context of magic square.

   hep-phInt.J.Mod.Phys.A(2022)·4 citations
3. 03*

   Mass matrices with CP phase in modular flavor symmetry

   Shota Kikuchi🇯🇵 · Tatsuo Kobayashi🇯🇵 · Morimitsu Tanimoto🇯🇵 · Hikaru Uchida🇯🇵

   We study the CP violation and the CP phase of quark mass matrices in modular flavor symmetric models. The CP symmetry remains at $\tau =e^{2\pi i/3}$ by a combination of the $T$-symmetry of the modular symmetry. However, the $T$-symmetry breaking may lead to the CP violation at the fixed point $\tau =e^{2\pi i/3}$. We study such a possibility in magnetized orbifold models as examples of modular flavor symmetric models. These models, in general, have more than one candidates for Higgs modes, while generic string compactifications also lead to several Higgs modes. These Higgs modes have different behaviors under the $T$-transformation. The light Higgs mode can be a linear combination of those modes so as to lead to realistic quark mass matrices. The CP phase of mass matrix does not appear in a certain case, which is determined by the $T$-transformation behavior. Deviation from it is important to realize the physical CP phase. We discuss an example leading to non-vanishing CP phase at the fixed point $\tau =e^{2\pi i/3}$.

   hep-phhep-thPTEP(2022)·18 citations
4. 04*

   Axial vectors in DarkCast

   Chaja Baruch🇮🇱 · Philip Ilten🇺🇸 · Yotam Soreq🇮🇱 · Mike Williams🇺🇸

   In this work, we explore new spin-1 states with axial couplings to the standard model fermions. We develop a data-driven method to estimate their hadronic decay rates based on data from $\tau$ decays and using SU(3)${}_{\mathrm{flavor}}$ symmetry. We derive the current and future experimental constraints for several benchmark models. Our framework is generic and can be used for models with arbitrary vectorial and axial couplings to quarks. We have made our calculations publicly available by incorporating them into the DarkCast package, see https://gitlab.com/darkcast/releases.

   hep-phhep-exJHEP(2022)·45 citations
5. 05*

   Inelastic nuclear scattering from neutrinos and dark matter

   Bhaskar Dutta🇺🇸 · Wei-Chih Huang🇺🇸 · Jayden L. Newstead🇦🇺 · Vishvas Pandey🇺🇸

   Neutrinos with energy of order 10~MeV, such as from pion decay-at-rest sources, are an invaluable tool for studying low-energy neutrino interactions with nuclei -- previously enabling the first measurement of coherent elastic neutrino-nucleus scattering. Beyond elastic scattering, neutrinos and dark matter in this energy range also excite nuclei to its low-lying nuclear states, providing an additional physics channel. Here, we consider neutral-current inelastic neutrino-nucleus and dark matter(DM)-nucleus scattering off ${}^{40}$Ar, ${}^{133}$Cs, and ${}^{127}$I nuclei that are relevant to a number of low-threshold neutrino experiments at pion decay-at-rest facilities. We carry out large scale nuclear shell model calculations of the inelastic cross sections considering the full set of electroweak multipole operators. Our results demonstrate that Gamow-Teller transitions provide the dominant contribution to the cross section and that the long-wavelength limit provides a reasonable approximation to the total cross section for neutrino sources. We show that future experiments will be sensitive to this channel and thus these results provide additional neutrino and DM scattering channels to explore at pion decay-at-rest facilities.

   hep-phnucl-thPRD(2022)·20 citations
6. 06*

   Study of entropy production due to electroweak phase transition in $Z_2$ symmetric extension of the Standard Model

   Arnab Chaudhuri🇮🇳 · Jaydeb Das🇮🇳

   In this work we consider the simple $Z_2$ symmetric extension to the Standard Model (SM) and proceed to study the nature of electroweak phase transition (EWPT) in the early universe. We show that the nature of the phase transition changes from a smooth crossover in the SM to a strong first order with this addition of the real scalar. Furthermore, we show the entropy release in this scenario is higher than that of the SM. This can lead to a strong dilution of frozen out dark matter particles and baryon asymmetry, if something existed before the onset of the phase transition.

   hep-phPRD(2022)·11 citations
7. 07*

   Transverse Momentum Dependent Fragmentation Functions from recent BELLE data

   M. Boglione🇮🇹 · J.O. Gonzalez-Hernandez🇮🇹 · A. Simonelli🇮🇹

   A new formalism for the factorization of the cross section for single hadron production in $e^{+}{e}^{-}$ annihilations, differential in $z_h$, $P_T$ and thrust, is applied to the phenomenological analysis of data recently measured by the BELLE Collaboration. Within this scheme the $e^{+}{e}^{-}\to hX$ cross section can be recast in the convolution of a perturbatively calculable coefficient and a universal transverse momentum dependent fragmentation function. While performing a next-to-leading order calculation of the perturbative part of the process to next-to-leading logarithmic accuracy, we examine and thoroughly discuss the suitability of a number of possible ansatz to model the non-perturbative part of this universal transverse momentum dependent fragmentation function, showing the extent to which present experimental data can actually constrain its shape and functional form in terms of $z_h$, $P_T$ and thrust.

   hep-phPRD(2022)·23 citations
8. 08*

   SYMBA: Symbolic Computation of Squared Amplitudes in High Energy Physics with Machine Learning

   Abdulhakim Alnuqaydan🇺🇸 · Sergei Gleyzer🇺🇸 · Harrison Prosper🇺🇸

   The cross section is one of the most important physical quantities in high-energy physics and the most time consuming to compute. While machine learning has proven to be highly successful in numerical calculations in high-energy physics, analytical calculations using machine learning are still in their infancy. In this work, we use a sequence-to-sequence model, specifically, a transformer, to compute a key element of the cross section calculation, namely, the squared amplitude of an interaction. We show that a transformer model is able to predict correctly 97.6% and 99% of squared amplitudes of QCD and QED processes, respectively, at a speed that is up to orders of magnitude faster than current symbolic computation frameworks. We discuss the performance of the current model, its limitations and possible future directions for this work.

   hep-phcs.LGMach.Learn.Sci.Tech.(2023)·24 citations
9. 09*

   Scalar Dark Matter Production from Preheating and Structure Formation Constraints

   Marcos A. G. Garcia🇲🇽 · Mathias Pierre🇩🇪 · Sarunas Verner🇺🇸

   We investigate the out-of-equilibrium production of scalar dark matter (DM) from the inflaton condensate during inflation and reheating. We assume that this scalar couples only to the inflaton via a direct quartic coupling and is minimally coupled to gravity. We consider all possible production regimes: purely gravitational, weak direct coupling (perturbative), and strong direct coupling (non-perturbative). For each regime, we use different approaches to determine the dark matter phase space distribution and the corresponding relic abundance. For the purely gravitational regime, scalar dark matter quanta are copiously excited during inflation resulting in an infrared (IR) dominated distribution function and a relic abundance which overcloses the universe for a reheating temperature $T_{\text{reh}}>34\text{GeV}$. A non-vanishing direct coupling induces an effective DM mass and suppresses the large IR modes in favor of ultraviolet (UV) modes and a minimal scalar abundance is generated when the interference between the direct and gravitational couplings is maximal. For large direct couplings, backreaction on the inflaton condensate is accounted for by using the Hartree approximation and lattice simulation techniques. Since scalar DM candidates can behave as non-cold dark matter, we estimate the impact of such species on the matter power spectrum and derive the corresponding constraints from the Lyman-$\alpha$ measurements. We find that they correspond to a lower bound on the DM mass of $\gtrsim 3\times 10^{-4}\mathrm{eV}$ for purely gravitational production, and $\gtrsim 20\mathrm{eV}$ for direct coupling production. We discuss the implications of these results.

   hep-phastro-ph.COgr-qchep-thPRD(2023)·62 citations
10. 10*

    Constraining axion-like particles with the diffuse gamma-ray flux measured by the Large High Altitude Air Shower Observatory

    Leonardo Mastrototaro🇮🇹 · Pierluca Carenza🇸🇪 · Marco Chianese🇮🇹 · Damiano F.G. Fiorillo🇩🇰 · Gennaro Miele🇮🇹 · Alessandro Mirizzi🇮🇹 · Daniele Montanino🇮🇹

    The detection of very high-energy neutrinos by IceCube experiment supports the existence of a comparable gamma-ray counterpart from the same cosmic accelerators. Under the likely assumption that the sources of these particles are of extragalactic origin, the emitted photon flux would be significantly absorbed during its propagation over cosmic distances. However, in the presence of photon mixing with ultra-light axion-like-particles (ALPs), this expectation would be strongly modified. Notably, photon-ALP conversions in the host galaxy would produce an ALP flux which propagates unimpeded in the extragalactic space. Then, the back-conversion of ALPs in the Galactic magnetic field leads to a diffuse high-energy photon flux. In this context, the recent detection of the diffuse high-energy photon flux by the Large High Altitude Air Shower Observatory (LHAASO) allows us to exclude at the $95\%$ CL an ALP-photon coupling $g_{a\gamma }\gtrsim 3.9-7.8\times 10^{-11}\mathrm{Ge}{\mathrm{V}}^{-1}$ for $m_a\lesssim 4\times 10^{-7}\mathrm{eV}$, depending on the assumptions on the magnetic fields and on the original gamma-ray spectrum. This new bound is complementary with other ALP constraints from very-high-energy gamma-ray experiments and sensitivities of future experiments.

    hep-phastro-ph.HEEPJC(2022)·23 citations
11. 11*

    Slow-Roll Inflation in the Jordan Frame

    Mindaugas Karčiauskas🇪🇸 · José Jaime Terente Díaz🇪🇸

    Inflation models based on scalar-tensor theories of gravity are formulated in the Jordan frame but most often analysed in the Einstein frame. The transformation between the frames is not always desirable. In this work we formulate slow-roll conditions in the Jordan frame. This is achieved by comparing different background quantities and approximations on the same spatial slice in both frames. We use these approximations to derive simple equations that can be applied to compute inflation model observables in terms of Jordan frame quantities only. Finally, we apply some of the results to analyse generalised induced gravity models and compare them with the latest observations.

    ↳ gr-qcastro-ph.COhep-phPRD(2022)·21 citations
12. 12*

    Bubble nucleation and quantum initial conditions in classical statistical simulations

    Anders Tranberg🇳🇴 · Gerhard Ungersbäck🇳🇴

    Classical-statistical lattice simulations provide a useful approximation to out-of-equilibrium quantum field theory, but only for systems exhibiting large occupation numbers, and only for phenomena that are not intrinsically quantum mechanical in nature. In certain special circumstances, it can be appropriate to initialize such real-time simulations with quantum-like zero-point fluctuations. We will revisit these points, and investigate reports that quantum bubble nucleation rates in 1+1 dimensions can be computed through the classical evolution of such a quantum-like initial condition. We find that although intriguing, the reported numerical agreement between classical-statistical simulations and the quantum nucleation rate in 1+1 dimensions is a coincidence, which is not specific to this choice of initialisation, is parameter and lattice cut-off dependent and disappears as the number of space-dimensions increases from 1+1 to 2+1

    ↳ hep-lathep-phhep-thJHEP(2022)·18 citations
13. 13*

    Testing chiral unitary models for the $\Lambda (1405)$ in $K^{+}\pi \Sigma$ photoproduction

    P. C. Bruns🇨🇿 · A. Cieplý🇨🇿 · M. Mai🇺🇸

    We adopt a novel formalism for the low-energy analysis of the $\gamma p\to K^{+}\pi \Sigma$ photoproduction reaction to calculate the $\pi \Sigma$ invariant mass distributions in the $\Lambda (1405)$ resonance region. The approach adheres to constraints arising from unitarity, gauge invariance and chiral perturbation theory, and is used without adjusting any model parameters. It is found that the meson-baryon rescattering in the final state has a major impact on the magnitude and structure of the generated spectra that are compared with the experimental data from the CLAS collaboration. We demonstrate a large sensitivity of the theoretical predictions to the choice of the coupled-channel $\pi \Sigma -\bar{K}N$ model amplitudes which should enable one to constrain the parameter space of these models.

    ↳ nucl-thhep-ph2 citations
14. 14*

    Evidence of a new excited charmed baryon decaying to ${\Sigma }_c(2455{)}^{0,++}{\pi }^{\pm }$

    Belle Collaboration: Y. B. Li🇨🇳 · C. P. Shen🇨🇳 · I. Adachi🇯🇵 · H. Aihara🇯🇵 · D. M. Asner🇺🇸 · H. Atmacan🇺🇸 · T. Aushev🇷🇺 · R. Ayad🇸🇦 · V. Babu🇩🇪 · S. Bahinipati🇮🇳 · P. Behera🇮🇳 · K. Belous🇷🇺 and 184 other authors

    We present the study of ${\bar{B}}^0\to {\Sigma }_c(2455{)}^{0,++}{\pi }^{\pm }\bar{p}$ decays based on $772\times 10^6$ $B\bar{B}$ events collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The ${\Sigma }_c(2455{)}^{0,++}$ candidates are reconstructed via their decay to ${\Lambda }_c^{+}{\pi }^{\mp }$ and ${\Lambda }_c^{+}$ decays to $p{K}^{-}{\pi }^{+},p{K}_S^0,$ and $\Lambda {\pi }^{+}$ final states. The corresponding branching fractions are measured to be $\mathcal{B}({\bar{B}}^0\to {\Sigma }_c(2455{)}^0{\pi }^{+}\bar{p})=(1.09\pm 0.06\pm 0.07)\times 10^{-4}$ and $\mathcal{B}({\bar{B}}^0\to {\Sigma }_c(2455{)}^{++}{\pi }^{-}\bar{p})=(1.84\pm 0.11\pm 0.12)\times 10^{-4}$, which are consistent with the world average values with improved precision. A new structure is found in the $M_{{\Sigma }_c(2455{)}^{0,++}{\pi }^{\pm }}$ spectrum with a significance of $4.2\sigma$ including systematic uncertainty. The structure is possibly an excited ${\Lambda }_c^{+}$ and is tentatively named ${\Lambda }_c(2910{)}^{+}$. Its mass and width are measured to be $(2913.8\pm 5.6\pm 3.8)$ MeV/$c^2$ and $(51.8\pm 20.0\pm 18.8)$ MeV, respectively. The products of branching fractions for the ${\Lambda }_c(2910{)}^{+}$ are measured to be $\mathcal{B}({\bar{B}}^0\to {\Lambda }_c(2910{)}^{+}\bar{p})\times \mathcal{B}({\Lambda }_c(2910{)}^{+}\to {\Sigma }_c(2455{)}^0{\pi }^{+})=(9.5\pm 3.6\pm 1.6)\times 10^{-6}$ and $\mathcal{B}({\bar{B}}^0\to {\Lambda }_c(2910{)}^{+}\bar{p})\times \mathcal{B}({\Lambda }_c(2910{)}^{+}\to {\Sigma }_c(2455{)}^{++}{\pi }^{-})=(1.24\pm 0.35\pm 0.10)\times 10^{-5}$. Here, the first and second uncertainties are statistical and systematic, respectively.

    ↳ hep-exhep-phPRL(2023)·32 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.