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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 289 records · Page 16
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DOE OSTI2025

Branching fraction measurement of the decay B + → ψ ( 2 S ) ϕ ( 1020 ) K +

The branching fraction of the decay B + → ψ ( 2 S ) ϕ ( 1020 ) K + , relative to the topologically similar decay B + → J / ψ ϕ ( 1020 ) K + , is measured using proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb − 1 . The ratio is found to be 0.061 ± 0.004 ± 0.009 , where the first uncertainty is statistical and the second systematic. Using the world-average branching fraction for B + → J / ψ ϕ ( 1020 ) K + , the branching fraction for the decay B + → ψ ( 2 S ) ϕ ( 1020 ) K + is found to be ( 3.0 ± 0.2 ± 0.5 ± 0.2 ) × 10 − 6 , where the first uncertainty is statistical, the second systematic, and the third is due to the branching fraction of the normalization channel. © 2025 CERN, for the LHCb Collaboration 2025 CERN

Aaij, R. (ORCID:0000000305331952)↗
DOE OSTI2025

Study of light-meson resonances decaying to K S 0 K π in the B → ( K S 0 K π ) K channels

A study is presented of B + → K S 0 K − π + K + and B + → K S 0 K + π − K + decays based on the analysis of proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb − 1 . The K S 0 K π invariant-mass distributions of both B + decay modes show, in the m ( K S 0 K π ) < 1.85 GeV mass region, large activity which is resolved using an amplitude analysis. A simple model, where J P C amplitudes are described by multiple Breit-Wigner functions with appropriate angular distributions, provides a good description of the experimental data. In this approach a complex mixture of J P C = 0 − + , 1 + + and 1 + − amplitudes is observed that is dominated by η ( 1405 ) , η ( 1470 ) , η ( 1760 ) , f 1 ( 1285 ) , f 1 ( 1420 ) and h 1 ( 1405 ) resonances. The K S 0 K π Dalitz plots are dominated by asymmetric crossing K * K ¯ bands which are different for the two B + decay modes. This is due to a different interference pattern between the 1 + + and 1 + − amplitudes in the two channels. Branching fractions are measured for each resonant contribution. © 2025 CERN, for the LHCb Collaboration 2025 CERN

Aaij, R. (ORCID:0000000305331952)↗
DOE OSTI2025

Search for D 0 meson decays to π + π − e + e − and K + K − e + e − final states

A search for D 0 meson decays to the π + π − e + e − and K + K − e + e − final states is reported using a sample of proton-proton collisions collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb − 1 . The decay D 0 → π + π − e + e − is observed for the first time when requiring that the two electrons are consistent with coming from the decay of a ϕ or ρ 0 / ω meson. The corresponding branching fractions are measured relative to the D 0 → K − π − [ e + e − ] ρ 0 / ω decay, where the two electrons are consistent with coming from the decay of a ρ 0 or ω meson. No evidence is found for the D 0 → K + K − e + e − decay and world-best limits are set on its branching fraction. The results are compared to, and found to be consistent with, the branching fractions of the D 0 → π + π − μ + μ − and D 0 → K + K − μ + μ − decays recently measured by LHCb and confirm lepton universality at the current precision. © 2025 CERN, for the LHCb Collaboration 2025 CERN

Aaij, R. (ORCID:0000000305331952)↗
DOE OSTI2025

Search for resonance-enhanced C P and angular asymmetries in the Λ c + → p μ + μ − decay at LHCb

The first measurement of the C P asymmetry of the decay rate ( A C P ) and the C P average ( Σ A FB ) and C P asymmetry ( Δ A FB ) of the forward-backward asymmetry in the muon system of Λ c + → p μ + μ − decays is reported. The measurement is performed using a data sample of proton-proton collisions, recorded by the LHCb experiment from 2016 to 2018 at a center-of-mass energy of 13 TeV, which corresponds to an integrated luminosity of 5.4 fb − 1 . The asymmetries are measured in two regions of dimuon mass near the ϕ -meson mass peak. The dimuon-mass integrated results are A C P = ( − 1.1 ± 4.0 ± 0.5 ) % , Σ A FB = ( 3.9 ± 4.0 ± 0.6 ) % , Δ A FB = ( 3.1 ± 4.0 ± 0.4 ) % , where the first uncertainty is statistical and the second systematic. The results are consistent with the conservation of C P symmetry and the Standard Model expectations. © 2025 CERN, for the LHCb Collaboration 2025 CERN

Aaij, R. (ORCID:0000000305331952)↗
DOE OSTI2025

Shapiro steps observed in a two-dimensional Yukawa solid modulated by a one-dimensional vibrational periodic substrate

Depinning dynamics of a two-dimensional (2D) solid dusty plasma modulated by a one-dimensional (1D) vibrational periodic substrate are investigated using Langevin dynamical simulations. As the uniform driving force increases gradually, from the overall drift velocity varying with the driving force, four significant Shapiro steps are discovered. The data analysis results indicate that, when the ratio of the frequency from the drift motion over potential wells to the external frequency from the modulation substrate is close to integers, dynamic mode locking occurs, corresponding to the discovered Shapiro steps. In conclusion, around both termini of the first and fourth Shapiro steps, the transitions are found to be always continuous, however, the transition between the second and third Shapiro steps is discontinuous, probably due to the different arrangements of particles.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Improved Spatial Resolution Achieved by Chromatic Intensity Interferometry

Interferometers are widely used in imaging technologies to achieve enhanced spatial resolution, but require that the incoming photons be indistinguishable. In previous work, we built and analyzed color erasure detectors which expand the scope of intensity interferometry to accommodate sources of different colors. Here we demonstrate experimentally how color erasure detectors can achieve improved spatial resolution in an imaging task, well beyond the diffraction limit. Utilizing two 10.9 mm-aperture telescopes and a 0.8 m baseline, we measure the distance between a 1063.6 nm source and a 1064.4 nm source separated by 4.2 mm at a distance of 1.43 km, which surpasses the diffraction limit of a single telescope by about 40 times. Moreover, chromatic intensity interferometry allows us to recover the phase of the Fourier transform of the imaged objects – a quantity that is, in the presence of modest noise, inaccessible to conventional intensity interferometry.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2023

Observation of a J / ψ Λ Resonance Consistent with a Strange Pentaquark Candidate in B - → J / ψ Λ p ¯ Decays

An amplitude analysis of Β - → J/ψ⁢Λ⁢$\overline{p}$ decays is performed using 4400 signal candidates selected on a data sample of pp collisions recorded at center-of-mass energies of 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 9 fb -1 . A narrow resonance in the J/ψ⁢Λ system, consistent with a pentaquark candidate with strangeness, is observed with high significance. The mass and the width of this new state are measured to be 4338.2±0.7±0.4 MeV and 7.0±1.2±1.3 MeV, where the first uncertainty is statistical and the second systematic. The spin is determined to be 1/2 and negative parity is preferred. Because of the small Q-value of the reaction, the most precise single measurement of the B- mass to date, 5279.44±0.05±0.07 MeV, is obtained.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

First Observation of a Doubly Charged Tetraquark and Its Neutral Partner

A combined amplitude analysis is performed for the decays $B^0$ → $\overline{D}$ 0 $D_s^+$$π^–$ and $B^+$ → $D^–$$D_s^+$$π^+$, which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb –1 . Two new resonant states with masses of 2.908 ± 0.011 ± 0.020 GeV and widths of 0.136 ± 0.023 ± 0.013 GeV are observed, which decay to $D_s^+$$π^+$ and $D_s^+$$π^–$ respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content [c$\overline{s}$u$\overline{d}$], and the latter state is a neutral tetraquark composed of [c$\overline{s}$$\overline{u}$d] quarks. Both states are found to have spin-parity of 0 + , and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Nuclear Modification Factor of Neutral Pions in the Forward and Backward Regions in p - Pb Collisions

The nuclear modification factor of neutral pions is measured in proton-lead collisions collected at a center-of-mass energy per nucleon of 8.16 TeV with the LHCb detector. The π 0 production cross section is measured differentially in transverse momentum (p T ) for 1.5 < p Τ < 10.0 GeV and in center-of-mass pseudorapidity (η c.m. ) regions 2.5 < η c.m. < 3.5 (forward) and -4.0 < η c.m .< -3.0 (backward) defined relative to the proton beam direction. The forward measurement shows a sizable suppression of π 0 production, while the backward measurement shows the first evidence of π 0 enhancement in proton-lead collisions at the LHC. Together, these measurements provide precise constraints on models of nuclear structure and particle production in high-energy nuclear collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Test of Lepton Universality in b → $s$$\ell$ + $\ell$ – Decays

The first simultaneous test of muon-electron universality using $B^+$ → $K^+$$\ell^+$$\ell^–$ and $B^0$ → $K^{*0}$$\ell^+$$\ell^–$ decays is performed, in two ranges of the dilepton invariant-mass squared, q 2 . The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb –1 . Each of the four lepton universality measurements reported is either the first in the given q 2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Evidence for Modification of $b$ Quark Hadronization in High-Multiplicity $pp$ Collisions at $\sqrt{s}$ = 13 TeV

The production rate of $B^{0}_{s}$ mesons relative to $B^0$ mesons is measured by the LHCb experiment in $pp$ collisions at a center-of-mass energy $\sqrt{s}$ = 13 TeV over the forward rapidity interval 2 < $y$ < 4.5 as a function of the charged particle multiplicity measured in the event. Evidence at the 3.4$σ$ level is found for an increase of the ratio of $B^{0}_{s}$ to $B^0$ cross sections with multiplicity at transverse momenta below 6 GeV /$c$, with no significant multiplicity dependence at higher transverse momentum. Comparison with data from $e^+$ $e^–$ collisions implies that the density of the hadronic medium may affect the production rates of $B$ mesons. This is qualitatively consistent with the emergence of quark coalescence as an additional hadronization mechanism in high-multiplicity collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Observation of a Resonant Structure near the D s + D s - Threshold in the B + → D s + D s - K + Decay

An amplitude analysis of the B + → $D^{+}_{s}$ $D^{-}_{s}$ ⁢K + decay is carried out to study for the first time its intermediate resonant contributions, using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. A near-threshold peaking structure, referred to as X⁡(3960), is observed in the $D^{+}_{s}$ $D^{-}_{s}$ invariant-mass spectrum with significance greater than 12 standard deviations. The mass, width, and the quantum numbers of the structure are measured to be 3956 ± 5 ± 10 MeV, 43 ± 13 ± 8 MeV, and J P⁢C = 0 ++ , respectively, where the first uncertainties are statistical and the second systematic. The properties of the new structure are consistent with recent theoretical predictions for a state composed of c$\overline{c}$s$\overline{s}$ quarks. Evidence for an additional structure is found around 4140 MeV in the $D^{+}_{s}$ $D^{-}_{s}$ invariant mass, which might be caused either by a new resonance with the 0 ++ assignment or by a J/ψ⁢Φ ↔ $D^{+}_{s}$ $D^{-}_{s}$ coupled-channel effect.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of the Branching Fractions $\mathcal{B}(B^0 → p\bar{p}p\bar{p})$ and $\mathcal{B}(B^0_S → p\bar{p}p\bar{p})$

Searches for the rare hadronic decays $B^0 → p\bar{p}p\bar{p}$ and $B^0_S → p\bar{p}p\bar{p}$ are performed using proton-proton collision data recorded by the LHCb experiment and corresponding to an integrated luminosity of 9 fb –1 . Significances of 9.3⁢σ and 4.0⁢σ, including statistical and systematic uncertainties, are obtained for the $B^0 → p\bar{p}p\bar{p}$ and $B^0_S → p\bar{p}p\bar{p}$ signals, respectively. The branching fractions are measured relative to the topologically similar normalization decays B 0 → J/ψ⁢(→ $p\bar{p}$)⁢K* 0 ⁡(→ K + ⁡π – ) and B$^0_s$→J/ψ⁢(→ $p\bar{p}$) $\phi$(→K + ⁢K – ). The branching fractions are measured to be $\mathcal{B}(B^0 → p\bar{p}p\bar{p})$ = (2.2 ± 0.4 ± 0.1 ± 0.1)×10 –8 and $\mathcal{B}(B^0_S → p\bar{p}p\bar{p})$ = (2.3 ± 1.0 ± 0.2 ± 0.1)×10 –8 . In these measurements, the first uncertainty is statistical, the second is systematic, and the third one is due to the external branching fraction of the normalization channel.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of the Ratios of Branching Fractions R ( D * ) and R ( D 0 )

The ratios of branching fractions $R(D*)$ ≡ $B(\overline{B} → D*τ^-\overline{ν}_μ$)/$B$($\overline{B}$ → $D*μ^-\overline{ν}_μ$) and $R$($D$ 0 ) ≡ $B$($B$ - → $D^0τ^-\overline{v}_τ$)/$B$($B$ - → $D^0μ^-\overline{v}_μ$) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb -1 of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $τ^-$ → $μ^-ν_τ\overline{ν}_μ$. The measured values are $R$($D$*) = 0.281 ± 0.018 ± 0.024 and $R$($D$ 0 ) = 0.441 ± 0.060 ± 0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $ρ$ = -0.43. The results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the standard model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Evidence of a $J/$$\psi$$K_S^0$ Structure in $B^0$ → $J/$$\psi$$\phi$$K_S^0$

An amplitude analysis of $B^0$ → $J/$$\psi$$\phi$$K_S^0$ decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 9 fb –1 , collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. Evidence with a significance of 4.0 standard deviations of a structure in the $J/$$\psi$$K_S^0$ system, named $T_{ψs1}^{θ}$⁢⁢(4000) 0 , is seen, with its mass and width measured to be 3991$_{–10 –17}^{+12 +9}$ MeV/⁢c 2 and 105$_{–25 –23}^{+29 +17}$ MeV, respectively, where the first uncertainty is statistical and the second systematic. The $T_{ψs1}^{θ}$⁢⁢(4000) 0 state is likely to be the isospin partner of the $T_{ψs1}^{θ}$⁢⁢(4000) + state, previously observed in the $J/ψK^+$ system of the $B^+$→$J/ψ$$\phi$$K^+$ decay. When isospin symmetry for the charged and neutral $T_{ψs1}^{θ}$⁢⁢(4000) states is assumed, the signal significance increases to 5.4 standard deviations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Observation of New Ω c 0 States Decaying to the Ξ c + K - Final State

Two new excited states, Ω c (3185) 0 and Ω c ⁢(3327) 0 , are observed in the $Ξ^{+}_{c}$K - invariant-mass spectrum using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb -1 . Five previously observed excited $Ω^{0}_{c}$ states are confirmed, namely Ω c ⁢(3000) 0 , Ω c ⁢(3050) 0 , Ω c⁢ (3065) 0 , Ω c⁢ (3090) 0 , and Ω c⁢ (3119) 0 . The masses and widths of these seven states are measured with the highest precision to date.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Measurement of C P Violation in B 0 → ψ ( → ℓ + ℓ − ) K S 0 ( → π + π − ) Decays

A measurement of time-dependent C P violation in the decays of B 0 and B ¯ 0 mesons to the final states J / ψ ( → μ + μ − ) K S 0 , ψ ( 2 S ) ( → μ + μ − ) K S 0 and J / ψ ( → e + e − ) K S 0 with K S 0 → π + π − is presented. The data correspond to an integrated luminosity of 6 fb − 1 collected at a center-of-mass energy of s = 13 TeV with the LHCb detector. The C P -violation parameters are measured to be S ψ K S 0 = 0.717 ± 0.013 ( stat ) ± 0.008 ( syst ) and C ψ K S 0 = 0.008 ± 0.012 ( stat ) ± 0.003 ( syst ) . This measurement of S ψ K S 0 represents the most precise single measurement of the CKM angle β to date and is more precise than the current world average. In addition, measurements of the C P -violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed. © 2024 CERN, for the LHCb Collaboration 2024 CERN

Aaij, R. (ORCID:0000000305331952)↗