Precision Measurements of and

Physical Review D

A light scalar X 0 or vector X 1 particles have been introduced as a possible explanation for the (g− 2) μ anomaly and dark matter phenomena. Using (8.998±0.039)× 10 9 J/ψ events collected by the BESIII detector, we search for a light muon philic scalar X 0 or vector X 1 in the processes J/ψ→ μ+ μ− X 0, 1 with X 0, 1 invisible decays. No obvious signal is found, and the upper limits on the coupling g 0, 1′ between the muon and the X 0, 1 particles are set to be between 1.1× 10− 3 and 1.0× 10− 2 for the X 0, 1 mass in the range of 1< M (X 0, 1)< 1000 MeV/c 2 at 90% credibility level.

Physical Review D

Based on 7.33 fb− 1 of e+ e− collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, the experimental studies of the doubly Cabibbo-suppressed decays D s+→ K+ K+ π− and D s+→ K+ K+ π− π 0 are reported. We determine the absolute branching fraction of D s+→ K+ K+ π− to be (1.2 4− 0.26+ 0.28 (stat)±0.06 (syst))× 10− 4. No significant signal of D s+→ K+ K+ π− π 0 is observed and the upper limit on its decay branching fraction at 90% confidence level is set to be 1.7× 10− 4.

arXiv preprint arXiv:2312.10962

We present cross sections for the reaction at center-of-mass energies ranging from 3.51 GeV to 4.95 GeV using data samples collected in the BESIII experiment, corresponding to a total integrated luminosity of 26.5 fb. The ratio of neutral-to-charged kaon form factors at large momentum transfers () is determined to be , which indicates a small but significant effect of flavor-SU(3) breaking in the kaon wave function, and consequently excludes the possibility that flavor-SU(3) breaking is the primary reason for the strong experimental violation of the pQCD prediction , where and are the form factors, and and are the decay constants of charged pions and kaons, respectively. We also observe a significant signal for the charmless decay for the first time. Within a contour of the likelihood value, the the branching fraction for is determined to be , and the relative phase between the continuum and amplitudes is . The branching fraction is in good agreement with the - and -wave charmonia mixing scheme proposed in the interpretation of the " puzzle" between and decays.

Physical Review D

The Born cross sections and effective form factors of the process e+ e−→ Λ Σ 0+ c. c. are measured at 14 center-of-mass energy points from 2.3094 to 3.0800 GeV, based on data corresponding to an integrated luminosity of (478.5±4.8) pb− 1 collected with the BESIII detector. A nonzero Born cross section is observed at the center-of-mass energy of 2.3094 GeV with a statistical significance of more than five standard deviations, and the cross sections at other energies are obtained with improved precision compared to earlier measurements from the BABAR Collaboration. The Born cross-section line shape is described better by a shape considering the strong-interaction effects than by a pQCD motivated functional form.

arXiv preprint arXiv:2404.04640

We search for the di-photon decay of a light pseudoscalar axion-like particle, , in radiative decays of the , using 10 billion events collected with the BESIII detector. We find no evidence of a narrow resonance and set upper limits at the confidence level on the product branching fraction and the axion-like particle photon coupling constant in the ranges of and GeV, respectively, for GeV/. These are the most stringent limits to date in this mass region.

Physical review letters

Using a sample of (10087±44)×10^{6} J/ψ events, which is about 45 times larger than that was previously analyzed, a further investigation on the J/ψ→γ3(π^{+}π^{-}) decay is performed. A significant distortion at 1.84 GeV/c^{2} in the line shape of the 3(π^{+}π^{-}) invariant mass spectrum is observed for the first time, which could be resolved by two overlapping resonant structures, X(1840) and X(1880). The new state X(1880) is observed with a statistical significance larger than 10σ. The mass and width of X(1880) are determined to be 1882.1±1.7±0.7 MeV/c^{2} and 30.7±5.5±2.4 MeV, respectively, which indicates the existence of a pp[over ¯] bound state.

arXiv preprint arXiv:2401.14720

We present measurements of the Born cross sections for the processes and at center-of-mass energies from 4.308 to 4.951 GeV. The measurements are performed with data samples corresponding to an integrated luminosity of 11.0 collected with the BESIII detector operating at the BEPCII storage ring. Assuming the signals come from a single resonance, the mass and width are determined to be MeV/ and MeV, respectively, which is consistent with the parameters of the well-established resonance . In addition, we also use one single resonance to describe the line shape, and determine the mass and width to be MeV/ and MeV, respectively. The structure of this line shape requires further understanding.

Small

Manganese‐based materials are regarded as the most prospective cathode materials because of their high natural abundance, low toxicity, and high specific capacity. Nevertheless, the low conductivity, poor cycling performance, and controversial energy storage mechanisms hinder their practical application. Here, the MnS0.5Se0.5 microspheres are synthesized by a two‐step hydrothermal approach and employed as cathode materials for aqueous zinc‐ion batteries (AZIBs) for the first time. Interestingly, in‐depth ex situ tests and electrochemical kinetic analyses reveal that MnS0.5Se0.5 is first irreversibly converted into low‐crystallinity ZnMnO3 and MnOx by in situ electrooxidation (MnS0.5Se0.5‐EOP) during the first charging process, and then a reversible co‐insertion/extraction of H+/Zn2+ occurs in the as‐obtained MnS0.5Se0.5‐EOP electrode during the subsequent discharging and charging processes …

Physical Review Letters

We perform for the first time an amplitude analysis of the decay D+→ K S 0 π+ η and report the observation of the decay D+→ K S 0 a 0 (980)+ using 2.93 fb− 1 of e+ e− collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector. As the only W-annihilation-free decay among D to a 0 (980) pseudoscalar, D+→ K S 0 a 0 (980)+ is the ideal decay in extracting the contributions of the W-emission amplitudes involving a 0 (980) and to study the final-state interactions. The absolute branching fraction of D+→ K S 0 π+ η is measured to be (1.27±0.0 4 stat±0.0 3 syst)%. The branching fractions of intermediate processes D+→ K S 0 a 0 (980)+ with a 0 (980)+→ π+ η and D+→ π+ K 0*(1430) 0 with K 0*(1430) 0→ K S 0 η are measured to be (1.33±0.0 5 stat±0.0 4 syst)% and (0.14±0.0 3 stat±0.0 1 syst)%, respectively.

Physical Review D

Based on a data sample of (2712.4±14.3)× 10 6 ψ (3686) events collected with the BESIII detector at the BEPCII collider, the M1 transition ψ (3686)→ γ η c (2 S) with η c (2 S)→ K Kπ is studied, where K Kπ is K+ K− π 0 or K S 0 K±π∓. The mass and width of the η c (2 S) are measured to be (3637.8±0.8 (stat)±0.2 (syst)) MeV/c 2 and (10.5±1.7 (stat)±3.5 (syst)) MeV, respectively. The product branching fraction B (ψ (3686)→ γ η c (2 S))× B (η c (2 S)→ K Kπ) is determined to be (0.97±0.06 (stat)±0.09 (syst))× 10− 5. Using B (η c (2 S)→ K Kπ)=(1.8 6− 0.49+ 0.68)%, we obtain the branching fraction of the radiative transition to be B (ψ (3686)→ γ η c (2 S))=(5.2±0.3 (stat)±0.5 (syst)− 1.4+ 1.9 (extr))× 10− 4, where the third uncertainty is due to the quoted B (η c (2 S)→ K Kπ).

The Circular Electron Positron Collider (CEPC) is a large scientific project initiated and hosted by China, fostered through extensive collaboration with international partners. The complex comprises four accelerators: a 30 GeV Linac, a 1.1 GeV Damping Ring, a Booster capable of achieving energies up to 180 GeV, and a Collider operating at varying energy modes (Z, W, H, and ttbar). The Linac and Damping Ring are situated on the surface, while the Booster and Collider are housed in a 100 km circumference underground tunnel, strategically accommodating future expansion with provisions for a Super Proton Proton Collider (SPPC). The CEPC primarily serves as a Higgs factory. In its baseline design with synchrotron radiation (SR) power of 30 MW per beam, it can achieve a luminosity of 5e34 /cm^2/s^1, resulting in an integrated luminosity of 13 /ab for two interaction points over a decade, producing 2.6 million Higgs bosons. Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons, facilitating precise measurements of Higgs coupling at sub-percent levels, exceeding the precision expected from the HL-LHC by an order of magnitude. This Technical Design Report (TDR) follows the Preliminary Conceptual Design Report (Pre-CDR, 2015) and the Conceptual Design Report (CDR, 2018), comprehensively detailing the machine's layout and performance, physical design and analysis, technical systems design, R&D and prototyping efforts, and associated civil engineering aspects. Additionally, it includes a cost estimate and a preliminary construction timeline, establishing a framework for …

Physical Review Letters

Based on data samples collected with the BESIII detector at the BEPCII collider, the process e+ e−→ Σ+ Σ− is studied at center-of-mass energies s= 2.3960, 2.6454, and 2.9000 GeV. Using a fully differential angular description of the final state particles, both the relative magnitude and phase information of the Σ+ electromagnetic form factors in the timelike region are extracted. The relative phase between the electric and magnetic form factors is determined to be sin Δ Φ=− 0.67±0.29 (stat)±0.18 (syst) at s= 2.3960 GeV, Δ Φ= 55±19 (stat)±14 (syst) at s= 2.6454 GeV, and 78±22 (stat)±9 (syst) at s= 2.9000 GeV. For the first time, the phase of the hyperon electromagnetic form factors is explored in a wide range of four-momentum transfer. The evolution of the phase along with four-momentum transfer is an important input for understanding its asymptotic behavior and the dynamics of baryons.

Physical Review D

Using a data sample of 4.481× 10 8 ψ (3686) events collected with the BESIII detector, we report the first observation of the four-lepton-decays J/ψ→ e+ e− e+ e− and J/ψ→ e+ e− μ+ μ− utilizing the process ψ (3686)→ π+ π− J/ψ. The branching fractions are determined to be [5.48±0.31 (stat)±0.45 (syst)]× 10− 5 and [3.53±0.22 (stat)±0.13 (syst)]× 10− 5, respectively. The results are consistent with theoretical predictions. No significant signal is observed for J/ψ→ μ+ μ− μ+ μ−, and an upper limit on the branching fraction is set at 1.6× 10− 6 at the 90% confidence level. A C P asymmetry observable is constructed for the first two channels, which is measured to be (− 0.012±0.054±0.010) and (0.062±0.059±0.006), respectively. No evidence for C P violation is observed in this process.

Journal of High Energy Physics

Using (10087±44)× 10 6 J/ψ events collected with the BESIII detector at the BEPCII e+ e− storage ring at the center-of-mass energy of= 3.097 GeV, we present a search for the rare semi-muonic charmonium decay J/ψ→ D− μ+ ν μ+ cc. Since no significant signal is observed, we set an upper limit of the branching fraction to be(J/ψ→ D− μ+ ν μ+ cc)< 5.6× 10− 7 at 90% confidence level. This is the first search for the weak decay of charmonium with a muon in the final state.

Physical Review Letters

Using e+ e− collision data corresponding to an integrated luminosity of 7.33 fb− 1 recorded by the BESIII detector at center-of-mass energies between 4.128 and 4.226 GeV, we present an analysis of the decay D s+→ π+ π− e+ ν e, where the D s+ is produced via the process e+ e−→ D s*±D s∓. We observe the f 0 (980) in the π+ π− system and the branching fraction of the decay D s+→ f 0 (980) e+ ν e with f 0 (980)→ π+ π− measured to be (1.72±0.1 3 stat±0.1 0 syst)× 10− 3, where the uncertainties are statistical and systematic, respectively. The dynamics of the D s+→ f 0 (980) e+ ν e decay are studied with the simple pole parametrization of the hadronic form factor and the Flatté formula describing the f 0 (980) in the differential decay rate, and the product of the form factor f+ f 0 (0) and the c→ s Cabibbo-Kobayashi-Maskawa matrix element| V c s| is determined for the first time to be f+ f 0 (0)| V c s|= 0.504±0.01 7 …

Physical review letters

The singly Cabibbo-suppressed decay Λ c+→ n π+ is observed for the first time with a statistical significance of 7.3 σ by using 3.9 fb− 1 of e+ e− collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λ c+→ n π+ is measured to be (6.6±1. 2 stat±0. 4 syst)× 10− 4. By taking the upper limit of branching fractions of Λ c+→ p π 0 from the Belle experiment, the ratio of branching fractions between Λ c+→ n π+ and Λ c+→ p π 0 is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with most predictions of the available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λ c+→ Λ π+ and Λ c+→ Σ 0 π+ are measured to be (1.31±0.0 8 stat±0.0 5 syst)× 10− 2 and (1.22±0.0 8 stat±0.0 7 syst)× 10− 2, respectively, which are consistent with previous results.

Physical Review Letters

We perform a study of the χ c 1 (3872) line shape using the data samples of e+ e−→ γ χ c 1 (3872), χ c 1 (3872)→ D 0 D 0 π 0, and π+ π− J/ψ collected with the BESIII detector. The effects of the coupled channels and the off-shell D* 0 are included in the parametrization of the line shape. The line shape mass parameter is obtained to be M X=(3871.63±0.1 3− 0.05+ 0.06) MeV. Two poles are found on the first and second Riemann sheets corresponding to the D* 0 D 0 branch cut. The pole location on the first sheet is much closer to the D* 0 D 0 threshold than the other, and is determined to be 7.04±0.1 5− 0.08+ 0.07 MeV above the D 0 D 0 π 0 threshold with an imaginary part− 0.19±0.0 8− 0.19+ 0.14 MeV.

arXiv preprint arXiv:2401.09225

The absolute branching fraction of the decay is measured for the first time to be with 368.48 pb of collision data collected by the BESIII detector at the center-of-mass energies of and GeV. This result is lower than the naive prediction of 67\%, obtained from isospin symmetry, by more than , thereby indicating that the novel mechanism referred to as the \textit{threshold effect}, proposed for the strong decays of , also applies to . This measurement is necessary to obtain the coupling constants for the transitions between -wave and -wave charmed baryons in heavy hadron chiral perturbation theory. In addition, we search for the decay . No significant signal is observed, and the upper limit on its branching fraction is determined to be 80.8\% at the 90\% confidence level.

Physical Review D

Using a data sample of 4.481× 10 8 ψ (3686) events collected with the BESIII detector, we report the first observation of the four-lepton-decays J/ψ→ e+ e− e+ e− and J/ψ→ e+ e− μ+ μ− utilizing the process ψ (3686)→ π+ π− J/ψ. The branching fractions are determined to be [5.48±0.31 (stat)±0.45 (syst)]× 10− 5 and [3.53±0.22 (stat)±0.13 (syst)]× 10− 5, respectively. The results are consistent with theoretical predictions. No significant signal is observed for J/ψ→ μ+ μ− μ+ μ−, and an upper limit on the branching fraction is set at 1.6× 10− 6 at the 90% confidence level. A C P asymmetry observable is constructed for the first two channels, which is measured to be (− 0.012±0.054±0.010) and (0.062±0.059±0.006), respectively. No evidence for C P violation is observed in this process.

Physical Review D

We present the first observation of the singly Cabibbo-suppressed decay Λ c+→ Λ K+ π 0 with a significance of 5.7 σ and the first evidence of Λ c+→ Λ K+ π+ π− decay with a significance of 3.1 σ, based on e+ e− annihilation data recorded by the BESIII detector at the BEPCII collider. The data correspond to an integrated luminosity of 6.4 fb− 1, in the center-of-mass energy range from 4.600 to 4.950 GeV. We determine the branching fractions of Λ c+→ Λ K+ π 0 and Λ c+→ Λ K+ π+ π− relative to their Cabibbo-favored counterparts to be B (Λ c+→ Λ K+ π 0) B (Λ c+→ Λ π+ π 0)=(2.09±0.3 9 stat±0.0 7 syst)× 10− 2 and B (Λ c+→ Λ K+ π+ π−) B (Λ c+→ Λ π+ π+ π−)=(1.13±0.4 1 stat±0.0 6 syst)× 10− 2, respectively. Moreover, by combining our measured result with the world average of B (Λ c+→ Λ π+ π 0), we obtain the branching fraction B (Λ c+→ Λ K+ π 0)=(1.49±0.2 7 stat±0.0 5 syst±0.0 8 ref)× 10− 3. This result …

Physical Review D

The precision with which hadronic vacuum polarization (HVP) is obtained determines how accurately important observables, such as the muon anomalous magnetic moment a μ or the low-energy running of the electromagnetic coupling α, are predicted. The two most precise approaches for determining HVP are dispersive relations combined with e+ e−→ hadrons cross section data and lattice QCD. However, the results obtained in these two approaches display significant tensions, whose origins are not understood. Here we present a framework that sheds light on this issue and—if the two approaches can be reconciled—allows them to be combined. Via this framework, we test the hypothesis that the tensions can be explained by modifying the R-ratio in different intervals of center-of-mass energy s. As ingredients, we consider observables that have been precisely determined in both approaches. These are the …

Physical Review D

A search for quantum black holes in electron+ jet and muon+ jet invariant mass spectra is performed with 140 fb− 1 of data collected by the ATLAS detector in proton-proton collisions at s= 13 TeV at the Large Hadron Collider. The observed invariant mass spectrum of lepton+ jet pairs is consistent with Standard Model expectations. Upper limits are set at 95% confidence level on the production cross section times branching fractions for quantum black holes decaying into a lepton and a quark in a search region with invariant mass above 2.0 TeV. The resulting quantum black hole lower mass threshold limit is 9.2 TeV in the Arkani-Hamed-Dimopoulos-Dvali model, and 6.8 TeV in the Randall-Sundrum model.

Physical Review D

A search for quantum black holes in electron+ jet and muon+ jet invariant mass spectra is performed with 140 fb− 1 of data collected by the ATLAS detector in proton-proton collisions at s= 13 TeV at the Large Hadron Collider. The observed invariant mass spectrum of lepton+ jet pairs is consistent with Standard Model expectations. Upper limits are set at 95% confidence level on the production cross section times branching fractions for quantum black holes decaying into a lepton and a quark in a search region with invariant mass above 2.0 TeV. The resulting quantum black hole lower mass threshold limit is 9.2 TeV in the Arkani-Hamed-Dimopoulos-Dvali model, and 6.8 TeV in the Randall-Sundrum model.

Physical Review D

In this work we analyze the motion of charged particles in the background of the Kiselev geometry, which is considered here as an exact solution in the context of power-Maxwell electrodynamics. As it is well known, one can use either an electric ansatz or a magnetic one for the nonlinear electromagnetic field. We study the motion of an electrically charged particle for an electrically charged black hole and also for a magnetically charged black hole. In the second case the motion is restricted to Poincaré cones of various angles, as expected.

Physical Review D

Ultracold atomic gases can undergo phase transitions that mimic relativistic vacuum decay, allowing us to empirically test early Universe physics in tabletop experiments. We investigate the physics of these analog systems, going beyond previous analyses of the classical equations of motion to study quantum fluctuations in the cold-atom false vacuum. We show that the fluctuation spectrum of this vacuum state agrees with the usual relativistic result in the regime where the classical analogy holds, providing further evidence for the suitability of these systems for studying vacuum decay. Using a suite of semiclassical lattice simulations, we simulate bubble nucleation from this analog vacuum state in a 1D homonuclear potassium-41 mixture, finding qualitative agreement with instanton predictions. We identify realistic parameters for this system that will allow us to study vacuum decay with current experimental …

Physical Review D

The evolution of linear initial conditions present in the early Universe into extended halos of dark matter at late times can be computed using cosmological simulations. However, a theoretical understanding of this complex process remains elusive; in particular, the role of anisotropic information in the initial conditions in establishing the final mass of dark matter halos remains a long-standing puzzle. Here, we build a deep learning framework to investigate this question. We train a three-dimensional convolutional neural network to predict the mass of dark matter halos from the initial conditions, and quantify in full generality the amounts of information in the isotropic and anisotropic aspects of the initial density field about final halo masses. We find that anisotropies add a small, albeit statistically significant amount of information over that contained within spherical averages of the density field about final halo mass …

Physical Review D

We investigate the hypothetical X17 boson on neutron stars and quark stars (QSs) using various hadronic equation of states (EoSs) with phenomenological or microscopic origin. Our aim is to set realistic constraints on its coupling constant and the mass scaling, with respect to causality and various possible upper mass limits and the dimensionless tidal deformability Λ 1.4. In particular, we pay special attention to two main phenomenological parameters of the X17, one is related to the coupling constant g that it has with hadrons or quarks and the other with the in-medium effects through regulator C. Both are very crucial concerning the contribution on the total energy density and pressure. In the case of considering the X17 as a carrier of nuclear force in relativistic mean field theory, an admixture into the vector boson segment was constrained by 20% and 30%. In our investigation, we came to the general conclusion …

Physical Review D

The recent analysis on the central compact object in the HESS J1731-347 remnant suggests interestingly small values for its mass and radius. Such an observation favors soft nuclear models that may be challenged by the observation of massive compact stars. In contrast, the recent PREX-II experiment, concerning the neutron skin thickness of Pb 208, points toward stiff equations of state that favor larger compact star radii. In the present study, we aim to explore the compatibility between stiff hadronic equations of state (favored by PREX-II) and the HESS J1731-347 remnant in the context of hybrid stars. For the construction of hybrid equations of state we use three widely employed Skyrme models combined with the well-known vector MIT bag model. Furthermore we consider two different scenarios concerning the energy density of the bag. In the first case, that of a constant bag parameter, we find that the resulting …

Physical Review D

The second Gravitational-Wave Transient Catalog, GWTC-2, reported on 39 compact binary coalescences observed by the Advanced LIGO and Advanced Virgo detectors between 1 April 2019 15∶ 00 UTC and 1 October 2019 15∶ 00 UTC. Here, we present GWTC-2.1, which reports on a deeper list of candidate events observed over the same period. We analyze the final version of the strain data over this period with improved calibration and better subtraction of excess noise, which has been publicly released. We employ three matched-filter search pipelines for candidate identification, and estimate the probability of astrophysical origin for each candidate event. While GWTC-2 used a false alarm rate threshold of 2 per year, we include in GWTC-2.1, 1201 candidates that pass a false alarm rate threshold of 2 per day. We calculate the source properties of a subset of 44 high-significance candidates that have a …

Physical Review D

We study the compact binary dynamics in the post-Newtonian approach implemented to the Einstein-Hilbert action adding the cosmological constant Λ at first post-Newtonian (1PN) order. We consider very small values of Λ finding that it plays the role of a PN factor to derive the Lagrangian of a compact two-body system at the center of mass frame at 1PN. Furthermore, the phase function ϕ (t) is obtained from the balance equation, and the two polarizations h+ and h× are also calculated. We observe changes due to Λ only at very low frequencies, and we notice that it plays the role of “stretch” the spacetime such that both amplitudes become smaller. However, given its nearly negligible value, Λ has no relevance at higher frequencies whatsoever.

Physical Review D

The nuclear reaction network within the interior of the Sun is an efficient MeV physics factory and can produce long-lived particles generic to dark sector models. In this work we consider the sensitivity of satellite instruments, primarily the RHESSI spectrometer, that observe the quiet Sun in the MeV regime where backgrounds are low. We find that quiet Sun observations offer a powerful and complementary probe in regions of parameter space, where the long-lived particle decay length is longer than the radius of the Sun and shorter than the distance between the Sun and Earth. We comment on connections to recent model-building work on heavy neutral leptons coupled to neutrinos and high-quality axions from mirror symmetries.

Physical Review D

Within the framework of relative and absolute quantum field theories (QFTs), we present a general formalism for understanding polarizations of the intermediate defect group and constructing noninvertible duality defects in theories in 2 k spacetime dimensions with self-dual gauge fields. We introduce the polarization pair, which fully specifies absolute QFTs as far as their (k− 1)-form defect groups are concerned, including their (k− 1)-form symmetries, global structures (including discrete θ-angle), and local counterterms. Using the associated symmetry topological field theory (TFT), we show that the polarization pair is capable of succinctly describing topological manipulations, eg, gauging (k− 1)-form global symmetries and stacking counterterms, of absolute QFTs. Furthermore, automorphisms of the (k− 1)-form charge lattice naturally act on polarization pairs via their action on the defect group; they can be viewed as …

Physical Review D

Recent measurements of charm-baryon production in hadronic collisions have questioned the universality of charm-quark fragmentation across different collision systems. In this work the fragmentation of charm quarks into charm baryons is probed, by presenting the first measurement of the longitudinal jet momentum fraction carried by Λ c+ baryons, z∥ ch, in hadronic collisions. The results are obtained in proton-proton (p p) collisions at s= 13 TeV at the LHC, with Λ c+ baryons and charged (track-based) jets reconstructed in the transverse momentum intervals of 3≤ p T Λ c+< 15 GeV/c and 7≤ p T jet ch< 15 GeV/c, respectively. The z∥ ch distribution is compared to a measurement of D 0-tagged charged jets in p p collisions as well as to pythia 8 simulations. The data hints that the fragmentation of charm quarks into charm baryons is softer with respect to charm mesons, in the measured kinematic interval, as …

Physical Review D

The second Gravitational-Wave Transient Catalog, GWTC-2, reported on 39 compact binary coalescences observed by the Advanced LIGO and Advanced Virgo detectors between 1 April 2019 15∶ 00 UTC and 1 October 2019 15∶ 00 UTC. Here, we present GWTC-2.1, which reports on a deeper list of candidate events observed over the same period. We analyze the final version of the strain data over this period with improved calibration and better subtraction of excess noise, which has been publicly released. We employ three matched-filter search pipelines for candidate identification, and estimate the probability of astrophysical origin for each candidate event. While GWTC-2 used a false alarm rate threshold of 2 per year, we include in GWTC-2.1, 1201 candidates that pass a false alarm rate threshold of 2 per day. We calculate the source properties of a subset of 44 high-significance candidates that have a …

Physical Review D

The second Gravitational-Wave Transient Catalog, GWTC-2, reported on 39 compact binary coalescences observed by the Advanced LIGO and Advanced Virgo detectors between 1 April 2019 15∶ 00 UTC and 1 October 2019 15∶ 00 UTC. Here, we present GWTC-2.1, which reports on a deeper list of candidate events observed over the same period. We analyze the final version of the strain data over this period with improved calibration and better subtraction of excess noise, which has been publicly released. We employ three matched-filter search pipelines for candidate identification, and estimate the probability of astrophysical origin for each candidate event. While GWTC-2 used a false alarm rate threshold of 2 per year, we include in GWTC-2.1, 1201 candidates that pass a false alarm rate threshold of 2 per day. We calculate the source properties of a subset of 44 high-significance candidates that have a …

Physical Review D

A search for quantum black holes in electron+ jet and muon+ jet invariant mass spectra is performed with 140 fb− 1 of data collected by the ATLAS detector in proton-proton collisions at s= 13 TeV at the Large Hadron Collider. The observed invariant mass spectrum of lepton+ jet pairs is consistent with Standard Model expectations. Upper limits are set at 95% confidence level on the production cross section times branching fractions for quantum black holes decaying into a lepton and a quark in a search region with invariant mass above 2.0 TeV. The resulting quantum black hole lower mass threshold limit is 9.2 TeV in the Arkani-Hamed-Dimopoulos-Dvali model, and 6.8 TeV in the Randall-Sundrum model.

Physical Review D

Recent measurements of charm-baryon production in hadronic collisions have questioned the universality of charm-quark fragmentation across different collision systems. In this work the fragmentation of charm quarks into charm baryons is probed, by presenting the first measurement of the longitudinal jet momentum fraction carried by Λ c+ baryons, z∥ ch, in hadronic collisions. The results are obtained in proton-proton (p p) collisions at s= 13 TeV at the LHC, with Λ c+ baryons and charged (track-based) jets reconstructed in the transverse momentum intervals of 3≤ p T Λ c+< 15 GeV/c and 7≤ p T jet ch< 15 GeV/c, respectively. The z∥ ch distribution is compared to a measurement of D 0-tagged charged jets in p p collisions as well as to pythia 8 simulations. The data hints that the fragmentation of charm quarks into charm baryons is softer with respect to charm mesons, in the measured kinematic interval, as …

Physical Review D

A search for quantum black holes in electron+ jet and muon+ jet invariant mass spectra is performed with 140 fb− 1 of data collected by the ATLAS detector in proton-proton collisions at s= 13 TeV at the Large Hadron Collider. The observed invariant mass spectrum of lepton+ jet pairs is consistent with Standard Model expectations. Upper limits are set at 95% confidence level on the production cross section times branching fractions for quantum black holes decaying into a lepton and a quark in a search region with invariant mass above 2.0 TeV. The resulting quantum black hole lower mass threshold limit is 9.2 TeV in the Arkani-Hamed-Dimopoulos-Dvali model, and 6.8 TeV in the Randall-Sundrum model.

Physical Review D

We use data from the Atacama Cosmology Telescope (ACT) DR4 to search for the presence of neutrino self-interaction in the cosmic microwave background. Consistent with prior works, the posterior distributions we find are bimodal, with one mode consistent with Λ CDM and one where neutrinos strongly self-interact. By combining ACT data with large-scale information from WMAP, we find that a delayed onset of neutrino free streaming caused by significantly strong neutrino self-interaction is compatible with these data at the 2− 3 σ level. As seen in the past, the preference shifts to Λ CDM with the inclusion of Planck data. We determine that the preference for strong neutrino self-interaction is largely driven by angular scales corresponding to 700≲ ℓ≲ 1000 in the ACT E-mode polarization data. This region is expected to be key to discriminate between neutrino self-interacting modes and will soon be probed with …

Physical Review D

We determine the fine-tuning of the Yukawa couplings of supersymmetric QCD, discretized on a lattice. We use perturbation theory at one-loop level. The modified minimal subtraction scheme (MS) is employed; by its definition, this scheme requires perturbative calculations, in the continuum and/or on the lattice. On the lattice, we utilize the Wilson formulation for gluon, quark, and gluino fields; for squark fields we use naive discretization. The sheer difficulties of this study lie in the fact that different components of squark fields mix among themselves at the quantum level and the action’s symmetries, such as parity and charge conjugation, allow an additional Yukawa coupling. Consequently, for an appropriate fine-tuning of the Yukawa terms, these mixings must be taken into account in the renormalization conditions. All Green’s functions and renormalization factors are analytic expressions depending on the number of …