Observation of decays to and

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 …

arXiv preprint arXiv:2310.12278

The production rate of baryons relative to mesons in collisions at a center-of-mass energy TeV is measured by the LHCb experiment. The ratio of to production cross-sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in collisions, and increases by a factor of with increasing multiplicity. At relatively low transverse momentum, the ratio of to cross-sections is higher than what is measured in collisions, but converges with the ratio as the momentum increases. These results imply that the evolution of heavy quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with a statistical hadronization model and implications for the mechanisms enforcing quark confinement are discussed.

Physical Review C

The production of η and η′ mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of 5.02 and 13 TeV and proton-lead collisions are studied at a center-of-mass energy per nucleon of 8.16 TeV. The studies are performed in center-of-mass (cm) rapidity regions 2.5< y c. m.< 3.5 (forward rapidity) and− 4.0< y c. m.<− 3.0 (backward rapidity) defined relative to the proton beam direction. The η and η′ production cross sections are measured differentially as a function of transverse momentum for 1.5< p T< 10 GeV and 3< p T< 10 GeV, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for η and η′ mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of η …

arXiv preprint arXiv:2401.17873

Using data samples collected with the BESIII detector operating at the BEPCII storage ring, the cross section of the inclusive process , normalized by the total cross section of , is measured at eight center-of-mass energy points from 2.0000 GeV to 3.6710 GeV. These are the first measurements with momentum dependence in this energy region. Our measurement shows a significant discrepancy from calculations with the existing fragmentation functions. To address this discrepancy, a new QCD analysis is performed at the next-to-next-to-leading order with hadron mass corrections and higher twist effects, which can explain both the established high-energy data and our measurements reasonably well.

Physical Review D

Using e+ e− collision data collected with the BESIII detector operating at the BEPCII collider, the Born cross sections of e+ e−→ Λ c+ Λc (2595)−+ c. c. and e+ e−→ Λ c+ Λc (2625)−+ c. c. are measured for the first time at center-of-mass energies of s= 4918.0 and 4950.9 MeV. Nonzero cross sections are observed very close to the production threshold. The measured Born cross sections of e+ e−→ Λ c+ Λc (2625)−+ c. c. are about 2–3 times greater than those of e+ e−→ Λ c+ Λc (2595)−+ c. c., providing the similar behavior as semileptonic decays of Λ b 0, but different behavior from that in the hadronic decays of Λ b 0. The Born cross sections are 15.6±3.1±0.9 pb and 29.4±3.7±2.7 pb for e+ e−→ Λ c+ Λc (2595)−+ c. c., and are 43.4±4.0±4.1 pb and 76.8±6.5±4.2 pb for e+ e−→ Λ c+ Λc (2625)−+ c. c. at s= 4918.0 and 4950.9 MeV, respectively. Based on the polar angle distributions of the Λc (2625)− and Λ c (2625)+, the …

arXiv preprint arXiv:2404.13840

Using data samples with an integrated luminosity of collected by the BESIII detector at center-of-mass energies ranging from 4.66 to 4.95 GeV, we study the processes of and . With the process, the branching fraction ratio is measured to be ( at 90\% confidence level). In addition, we measure the ratio of the average cross section of to to be $\sigma_{\omega X(3872)}/\sigma_{\omega\chi_{c1}}~(\sigma_{\omega X(3872)}/\sigma_{\omega\chi_{c2}})=5.2\pm1.0_\text{stat.}\pm1.9_\text{syst.}~ (5.5\pm1.1_\text{stat.}\pm2.4_\text{syst.})$. Finally, we search for the process of , and no obvious signal is observed. The upper limit on the ratio of the average cross section of to is set as at 90\% confidence level.

Physical Review Letters

Based on 4.4 fb− 1 of e+ e− annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure W-boson-exchange decay Λ c+→ Ξ 0 K+ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be α Ξ 0 K+= 0.01±0.16 (stat)±0.03 (syst). This result reflects the noninterference effect between the S-and P-wave amplitudes. The phase shift between S-and P-wave amplitudes has two solutions, which are δ p− δ s=− 1.55±0.25 (stat)±0.05 (syst) rad or 1.59±0.25 (stat)±0.05 (syst) rad.

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.

arXiv preprint arXiv:2404.13840

Using data samples with an integrated luminosity of collected by the BESIII detector at center-of-mass energies ranging from 4.66 to 4.95 GeV, we study the processes of and . With the process, the branching fraction ratio is measured to be ( at 90\% confidence level). In addition, we measure the ratio of the average cross section of to to be $\sigma_{\omega X(3872)}/\sigma_{\omega\chi_{c1}}~(\sigma_{\omega X(3872)}/\sigma_{\omega\chi_{c2}})=5.2\pm1.0_\text{stat.}\pm1.9_\text{syst.}~ (5.5\pm1.1_\text{stat.}\pm2.4_\text{syst.})$. Finally, we search for the process of , and no obvious signal is observed. The upper limit on the ratio of the average cross section of to is set as at 90\% confidence level.

arXiv preprint arXiv:2404.07436

The Born cross sections for the process are measured at 22 center-of-mass energies from 2.000 to 3.080 GeV using data collected with the BESIII detector at the BEPCII collider. A resonant structure is observed with a statistical significance of 9.6. A Breit-Wigner fit determines its mass to be and its width to be , where the first uncertainties are statistical and the second are systematic.

Journal of High Energy Physics

Based on e+ e− collision data collected at center-of-mass energies from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a partial wave analysis is performed for the process e+ e−→ π 0. The results allow the Born cross sections of the process e+ e−→ π 0, as well as its subprocesses e+ e−→ K∗(892) 0 0 and(1430) 0 0 to be measured. The Born cross sections for e+ e−→ π 0 are consistent with previous measurements by BaBar, but with substantially improved precision. The Born cross section lineshape of the process e+ e− K∗(892) 0 0 is consistent with a vector meson state around 2.2 GeV with a significance of 3.2σ. A Breit-Wigner fit determines its mass as M Y=(2164. 7±9. 1±3. 1) MeV/c 2 and its width as Γ Y=(32. 4±21. 0±1. 8) MeV.

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.

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 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:2402.01336

Measurements of the branching fraction ratio with and decays, denoted and , are presented. The analysis is performed using a dataset corresponding to an integrated luminosity of 5.4 of collision data collected with the LHCb experiment. The branching fractions are normalised with respect to the and decay modes. The combination of the results yields The result is compatible with previous measurements of the branching fractions and predictions based on the Standard Model.

PHYSICAL REVIEW D

Using a sample of 10 billion J/psi events collected with the BESIII detector, the decays eta' -> pi())pi(-)pi())pi(-), eta' -> pi())pi(-)pi(0)pi(0 )and eta'-> 4 pi(0 )are studied via the process J/psi -> gamma eta'. The branching fractions of eta'->pi())pi(-)pi())pi(- )and eta'->pi())pi(-)pi(0)pi(0 )are measured to be(8.56 +/- 0.25(stat)+/- 0.23(syst))x10(-5 )and (2.12 +/- 0.12(stat)+/- 0.10(syst))x10(-4), respectively, which are consistent with previous measurements but with improved precision. No significant eta'-> 4 pi(0 )signal is observed, and the upper limit on the branching fraction of this decay is determined to be less than 1.24x10(-5 )at the 90% confidence level. In addition, an amplitude analysis of eta'->pi)pi-pi)pi-is performed to extract the doubly virtual isovector form factor alpha for the first time. The measured value of alpha = 1.22 +/- 0.33(stat) +/- 0.04(syst), is in agreement with the prediction of the vector meson dominance model.

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.

Physical Review D

Using E1 radiative transitions ψ (3686)→ γ χ c J from a sample of (448.1±2.9)× 10 6 ψ (3686) events collected with the BESIII detector, the decays χ c J→ Σ+ p K S 0+ c. c.(J= 0, 1, 2) are studied. The decay branching fractions are measured to be B (χ c 0→ Σ+ p K S 0+ c. c.)=(3.52±0.19±0.21)× 10− 4, B (χ c 1→ Σ+ p K S 0+ c. c.)=(1.53±0.10±0.08)× 10− 4, and B (χ c 2→ Σ+ p K S 0+ c. c.)=(8.25±0.83±0.49)× 10− 5, where the first and second uncertainties are the statistical and systematic ones, respectively. No evident intermediate resonances are observed in the studied processes.

Physics Letters B

This letter reports the observation of W (ℓ ν) γ γ production in proton-proton collisions. This measurement uses the full Run 2 sample of events recorded at a center-of-mass energy of s= 13 TeV by the ATLAS detector at the LHC, corresponding to an integrated luminosity of 140 fb− 1. Events with a leptonically-decaying W boson and at least two photons are considered. The background-only hypothesis is rejected with an observed and expected significance of 5.6 standard deviations. The inclusive fiducial production cross section of W (e ν) γ γ and W (μ ν) γ γ events is measured to be σ fid= 13.8±1.1 (stat)+ 2.1− 2.0 (syst)±0.1 (lumi) fb, in agreement with the Standard Model prediction.

arXiv preprint arXiv:2401.08252

Using events collected with the BESIII detector at BEPCII, the decay of is observed for the first time. The branching fraction of this decay is measured to be $\mathcal{B}_{\psi(3686) \to \Omega^- K^+ \bar{\Xi}^0 +c.c.}=(2.78 \pm 0.40 \pm 0.18 ) \times 10^{-6}$, where the first uncertainty is statistical and the second is systematic. Possible baryon excited states are searched for in this decay, but no evident intermediate state is observed with the current sample size.

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 …