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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 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
DOE OSTI2010

Observation of B{sub s}{sup 0{yields}}D{sub s}*{sup -{pi}+} and B{sub s}{sup 0{yields}}D{sub s}{sup (*)-{rho}+} and Measurement of the B{sub s}{sup 0{yields}}D{sub s}*{sup -{rho}+} Longitudinal Polarization Fraction

First observations of the B{sub s}{sup 0{yields}}D{sub s}*{sup -{pi}+}, B{sub s}{sup 0{yields}}D{sub s}{sup -{rho}+} and B{sub s}{sup 0{yields}}D{sub s}*{sup -{rho}+} decays are reported together with measurements of their branching fractions: B(B{sub s}{sup 0{yields}}D{sub s}*{sup -{pi}+})=[2.4{sub -0.4}{sup +0.5}(stat){+-}0.3(syst){+-} 0.4(f{sub s})]x10{sup -3}, B(B{sub s}{sup 0{yields}}D{sub s}{sup -{rho}+})=[8.5{sub -1.2}{sup +1.3}(stat){+-}1.1(syst){+-}1.3(f{sub s})]x10{sup -3} and B(B{sub s}{sup 0{yields}}D{sub s}*{sup -{rho}+})=[11.9{sub -2.0}{sup +2.2}(stat){+-}1.7(syst){+-}1.8(f{sub s})]x10{sup -3} (f{sub s}=N{sub B{sub s}{sup (*)}B{sub s}{sup (*)}/N{sub bb}}). From helicity-angle distributions, we measured the longitudinal polarization fraction in B{sub s}{sup 0{yields}}D{sub s}*{sup -{rho}+} decays to be f{sub L}(B{sub s}{sup 0{yields}}D{sub s}*{sup -{rho}+})=1.05{sub -0.10}{sup +0.08}(stat){sub -0.04}{sup +0.03}(syst). These results are based on a 23.6 fb{sup -1} data sample collected at the {Upsilon}(5S) resonance with the Belle detector at the KEKB e{sup +}e{sup -} collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Evidence for the Suppressed Decay B{sup -}{yields}DK{sup -}, D{yields}K{sup +}{pi}{sup -}

The suppressed decay chain B{sup -}{yields}DK{sup -}, D{yields}K{sup +}{pi}{sup -}, where D indicates a D{sup 0} or D{sup 0} state, provides important information on the CP-violating angle {phi}{sub 3}. We measure the ratio R{sub DK} of the decay rates to the favored mode B{sup -}{yields}DK{sup -}, D{yields}K{sup -}{pi}{sup +} to be R{sub DK}=[1.63{sub -0.41}{sup +0.44}(stat){sub -0.13}{sup +0.07}(syst)]x10{sup -2}, which indicates the first evidence of the signal with a significance of 4.1{sigma}. We also measure the asymmetry A{sub DK} between the charge-conjugate decays to be A{sub DK}=-0.39{sub -0.28}{sup +0.26}(stat){sub -0.03}{sup +0.04}(syst). The results are based on the full 772x10{sup 6} BB pair data sample collected at the {Upsilon}(4S) resonance with the Belle detector.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Observation of Two Charged Bottomoniumlike Resonances in Υ ( 5 S ) Decays

We report the observation of two narrow structures in the mass spectra of the π±Υ(nS) (n=1, 2, 3) and π±hb(mP) (m=1, 2) pairs that are produced in association with a single charged pion in Υ(5S) decays. The measured masses and widths of the two structures averaged over the five final states are M1=(10 607.2±2.0) MeV/c 2 , Γ 1 =(18.4±2.4) MeV, and M 2 =(10 652.2±1.5) MeV/c 2 , Γ 2 =(11.5±2.2) MeV. The results are obtained with a 121.4 fb -1 data sample collected with the Belle detector in the vicinity of the Υ(5S) resonance at the KEKB asymmetric-energy e+e- collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Observation of New Resonant Structures in γ γ → ω Φ , Φ Φ , and ω ω

The processes γγ --> ωΦ, ΦΦ, and ωω are measured using an 870 fb -1 data sample collected with the Belle detector at the KEKB asymmetric-energy e + e - collider. Production of vector meson pairs is clearly observed and their cross sections are measured for masses that range from threshold to 4.0 GeV. In addition to signals from well established spin-zero and spin-two charmonium states, there are resonant structures below charmonium threshold, which have not been previously observed. We report a spin-parity analysis for the new structures and determine the products of the η c , χ c0 , and χ c2 two-photon decay widths and branching fractions to ωΦ, ΦΦ, and ωω.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Combined Search for the Standard Model Higgs Boson Decaying to bb̄ Using the D0 Run II Data Set

We present the results of the combination of searches for the standard model Higgs boson produced in association with a W or Z boson and decaying into bb̄ using the data sample collected with the D0 detector in pp̄ collisions at √s=1.96 TeV at the Fermilab Tevatron Collider. We derive 95% C.L. upper limits on the Higgs boson cross section relative to the standard model prediction in the mass range 100 GeV≤M H ≤150 GeV, and we exclude Higgs bosons with masses smaller than 102 GeV at the 95% C.L. In the mass range 120 GeV≤M H ≤145 GeV, the data exhibit an excess above the background prediction with a global significance of 1.5 standard deviations, consistent with the expectation in the presence of a standard model Higgs boson.

Abazov, V. M.↗
DOE OSTI2013

Study of e + e - → π + π - J / ψ and Observation of a Charged Charmoniumlike State at Belle

The cross section for $e^+e^-→π^+π^-J/ψ$ between 3.8 GeV and 5.5 GeV is measured with a 967 fb -1 data sample collected by the Belle detector at or near the $\Upsilon(nS)$ ($n=1, 2, ..., 5$) resonances. The $\Upsilon$(4260) state is observed, and its resonance parameters are determined. In addition, an excess of $π^+π^-J/ψ$ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parameterization with properties that are consistent with the $\Upsilon$(4008) state that was previously reported by Belle. In a study of $\Upsilon$(4260)→$π^+π^-J/ψ$ decays, a structure is observed in the $M(\pi^{\pm}J/ψ)$ mass spectrum with 5.2$σ$ significance, with mass M=(3894.5±6.6±4.5)MeV/$c^2$ and width $Γ$=(63±24±26) MeV/$c^2$, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmonium-like state.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Measurement of prompt ψ ( 2 S ) to J / ψ yield ratios in Pb-Pb and p - p collisions at s N N = 2.76 TeV

The ratio between the prompt ψ(2S) and J/ψ yields, reconstructed via their decays into μ⁺μ⁻, is measured in Pb-Pb and p-p collisions at √ s NN = 2.76 TeV. The analysis is based on Pb-Pb and p-p data samples collected by CMS at the Large Hadron Collider, corresponding to integrated luminosities of 150 μb⁻¹ and 5.4 pb⁻¹, respectively. The double ratio of measured yields (N ψ(2S) /N J/ψ ) Pb−Pb /(N ψ(2S) /N J/ψ ) p−p is computed in three Pb-Pb collision centrality bins and two kinematic ranges: one at midrapidity, |y| < 1.6, covering the transverse momentum range 6.5 < p T < 30 GeV/c, and the other at forward rapidity, 1.6<|y|<2.4, extending to lower pT values, 3<pT<30 GeV/c. The centrality-integrated double ratio changes from 0.45 ± 0.13 (stat) ± 0.07 (syst) in the first range to 1.67 ± 0.34 (stat) ± 0.27 (syst) in the second. This difference is most pronounced in the most central collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Measurement of J / ψ and ψ ( 2 S ) Prompt Double-Differential Cross Sections in p p Collisions at s = 7 TeV

The double-differential cross sections of promptly produced J/ψ and ψ(2S) mesons are measured in pp collisions at √s=7 TeV, as a function of transverse momentum pT and absolute rapidity |y|. The analysis uses J/ψ and ψ(2S) dimuon samples collected by the CMS experiment, corresponding to integrated luminosities of 4.55 and 4.90 fb⁻¹, respectively. The results are based on a two-dimensional analysis of the dimuon invariant mass and decay length, and extend to p T =120 and 100 GeV for the J/ψ and ψ(2S), respectively, when integrated over the interval |y|<1.2. The ratio of the ψ(2S) to J/ψ cross sections is also reported for |y|<1.2, over the range 10 T <100 GeV. These are the highest p T values for which the cross sections and ratio have been measured.

Khachatryan, V.↗
DOE OSTI2016

Observation of Z b ( 10610 ) and Z b ( 10650 ) Decaying to B Mesons

We detail the analysis of the three-body e + e - → B B ¯ π ± , B B ¯ * π ± , and B * B ¯ * π ± processes, including the first observations of the Z b ± ( 10 610 ) → [ B B ¯ * + c . c . ] ± and Z b ± ( 10 650 ) → [ B * B ¯ * ] ± transitions that are found to dominate the corresponding final states. We measure Born cross sections for the three-body production of σ ( e + e - → [ B B ¯ * + c . c . ] ± π ∓ ) = [ 17.4 ± 1.6 ( stat ) ± 1.9 ( syst ) ] pb and σ ( e + e - → [ B * B ¯ * ] ± π ∓ ) = [ 8.75 ± 1.15 ( stat ) ± 1.04 ( syst ) ] pb and set a 90% C.L. upper limit of σ ( e + e - → [ B B ¯ ] ± π ∓ ) < 2.9 pb . The results are based on a 121.4 fb - 1 data sample collected with the Belle detector at a center-of-mass energy near the Υ ( 10 860 ) peak.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Evidence of Two Resonant Structures in e + e - → π + π - h c

The cross sections of e + e - →π + π - h c at center-of-mass energies from 3.896 to 4.600 GeV are measured using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider. The cross sections are found to be of the same order of magnitude as those of e + e - →π + π - J/ψ and e + e - →π + π - ψ (2S), but the line shape is inconsistent with the Y states observed in the latter two modes. Two structures are observed in the e + e - → π + π - h c cross sections around 4.22 and 4.39 GeV / c 2 , which we call Y ( 4220 ) and Y ( 4390 ) , respectively. A fit with a coherent sum of two Breit-Wigner functions results in a mass of (4218.4 $+5.5\atop{-4.5 ± 0.9) MeV/c 2 and a width of 66.0$+12.3\atop-8.3$±0.4 MeV for the Y (4220), and a mass of (4391.5 $+6.3\atop-16.8$ ± 1.0) MeV/c 2 and a width of (139.5$+16.2\atop-20.6 ± 0.6) MeV for the Y (4390), where the first uncertainties are statistical and the second ones systematic. The statistical significance of Y ( 4220 ) and Y(4390) is 10σ over one structure assumption.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Measurement of the C P Violation Parameter A Γ in D 0 → K + K - and D 0 → π + π - Decays

Asymmetries in the time-dependent rates of D 0 →K + K - and D 0 →$π$ + $π$ - decays are measured in a $pp$ collision data sample collected with the LHCb detector during LHC Run 1, corresponding to an integrated luminosity of 3 fb -1 . The asymmetries in effective decay widths between $D$ 0 and $\bar{D}$ 0 decays, sensitive to indirect $CP$ violation, are measured to be A $Γ$ (K + K - ) = (-0.30 ± 0.32 ± 0.10) × 10 -3 and A $Γ$ ($π$ + $π$ - ) = (0.46 ± 0.58 ± 0.12) × 10 -3 , where the first uncertainty is statistical and the second systematic. These measurements show no evidence for $CP$ violation and improve on the precision of the previous best measurements by nearly a factor of two.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Determination of the Σ + Timelike Electromagnetic Form Factors

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. Published by the American Physical Society 2024

Physics↗
DOE OSTI2024

Observation of Significant Flavor-SU(3) Breaking in the Kaon Wave Function at 12 < Q 2 < 25 GeV 2 and Discovery of the Charmless Decay ψ ( 3770 ) → K S 0 K L 0

We present cross sections for the reaction e + e − → K S 0 K L 0 at center-of-mass energies ranging from 3.51 to 4.95 GeV using data samples collected in the BESIII experiment, corresponding to a total integrated luminosity of 26.5 fb − 1 . The ratio of neutral-to-charged kaon form factors at large momentum transfers ( 12 < Q 2 < 25 GeV 2 ) is determined to be 0.21 ± 0.01 , 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 | F ( π ± ) | / | F ( K ± ) | = f π 2 / f K 2 , where F ( π ± ) and F ( K ± ) are the form factors, and f π and f K are the decay constants of charged pions and kaons, respectively. We also observe a significant signal for the charmless decay ψ ( 3770 ) → K S 0 K L 0 for the first time. Within a 1 σ contour of the likelihood value, the branching fraction for ψ ( 3770 ) → K S 0 K L 0 is determined to be B = ( 2.6 3 − 1.59 + 1.40 ) × 10 − 5 , and the relative phase between the continuum and ψ ( 3770 ) amplitudes is ϕ = ( − 0.3 9 − 0.10 + 0.05 ) π . The branching fraction is in good agreement with the S - and D -wave charmonia mixing scheme proposed in the interpretation of the “ ρ π puzzle” between J / ψ and ψ ( 3686 ) decays. Published by the American Physical Society 2024

Physics↗
DOE OSTI2024

Measurements of Normalized Differential Cross Sections of Inclusive η Production in e + e − Annihilation at Energy from 2.0000 to 3.6710 GeV

Using data samples collected with the BESIII detector operating at the BEPCII storage ring, the cross section of the inclusive process e + e − → η + X , normalized by the total cross section of e + e − → hadrons , is measured at eight center-of-mass energy points from 2.0000 to 3.6710 GeV. These are the first measurements with momentum dependence in this energy region. Our measurement shows a significant discrepancy compared to 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. Published by the American Physical Society 2024

Physics↗
DOE OSTI2024

Precise Measurement of Born Cross Sections for e + e − → D D ¯ at s = 3.80 − 4.95 GeV

Using data samples collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from 3.80 to 4.95 GeV, corresponding to an integrated luminosity of 20 fb − 1 , a measurement of Born cross sections for the e + e − → D 0 D ¯ 0 and D + D − processes is presented with unprecedented precision. Many clear peaks in the line shape of e + e − → D 0 D ¯ 0 and D + D − around the mass range of G ( 3900 ) , ψ ( 4040 ) , ψ ( 4160 ) , Y ( 4260 ) , and ψ ( 4415 ) , etc., are foreseen. These results offer crucial experimental insights into the nature of hadron production in the open-charm region. Published by the American Physical Society 2024

Physics↗
DOE OSTI2024

Search for Time-Dependent C P Violation in D 0 → π + π − π 0 Decays

A measurement of time-dependent C P violation in D 0 → π + π − π 0 decays using a p p collision data sample collected by the LHCb experiment in 2012 and from 2015 to 2018, corresponding to an integrated luminosity of 7.7 fb − 1 , is presented. The initial flavor of each D 0 candidate is determined from the charge of the pion produced in the D * ( 2010 ) + → D 0 π + decay. The decay D 0 → K − π + π 0 is used as a control channel to validate the measurement procedure. The gradient of the time-dependent C P asymmetry Δ Y in D 0 → π + π − π 0 decays is measured to be Δ Y = ( − 1.3 ± 6.3 ± 2.4 ) × 10 − 4 , where the first uncertainty is statistical and the second is systematic, which is compatible with C P conservation. © 2024 CERN, for the LHCb Collaboration 2024 CERN

Aaij, R. (ORCID:0000000305331952)↗
DOE OSTI2024

Strong and Weak C P Tests in Sequential Decays of Polarized Σ 0 Hyperons

The J / ψ , ψ ( 3686 ) → Σ 0 Σ ¯ 0 processes and subsequent decays are studied using the world’s largest J / ψ and ψ ( 3686 ) data samples collected with the BESIII detector. The parity-violating decay parameters of the decays Σ 0 → Λ γ and Σ ¯ 0 → Λ ¯ γ , α Σ 0 = − 0.0017 ± 0.0021 ± 0.0018 and α ¯ Σ 0 = 0.0021 ± 0.0020 ± 0.0022 , are measured for the first time. The strong C P symmetry is tested in the decays of the Σ 0 hyperons for the first time by measuring the asymmetry A C P Σ = α Σ 0 + α ¯ Σ 0 = ( 0.4 ± 2.9 ± 1.3 ) × 10 − 3 . The weak C P test is performed in the subsequent decays of their daughter particles Λ and Λ ¯ . Also for the first time, the transverse polarizations of the Σ 0 hyperons in J / ψ and ψ ( 3686 ) decays are observed with opposite directions, and the ratios between the S -wave and D -wave contributions of the J / ψ , ψ ( 3686 ) → Σ 0 Σ ¯ 0 decays are obtained. These results are crucial to understand the decay dynamics of the charmonium states and the production mechanism of the Σ 0 − Σ ¯ 0 pairs. Published by the American Physical Society 2024

Physics↗