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At least 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Partial wave analysis of 𝑒 + ⁢𝑒 − → 𝜋 + ⁢𝜋 − ⁢𝐽/𝜓 and cross section measurement of 𝑒 + ⁢𝑒 − → 𝜋 ± ⁢𝑍 𝑐 ⁢(3900) ∓ from 4.1271 to 4.3583 GeV

Based on 12.0 fb −1 of 𝑒 + ⁢𝑒 − collision data samples collected by the BESIII detector at center-of-mass energies from 4.1271 to 4.3583 GeV, a partial wave analysis is performed for the process 𝑒 + ⁢𝑒 − → 𝜋 + ⁢𝜋 − ⁢𝐽/𝜓. The cross sections for the subprocesses 𝑒 + ⁢𝑒 − → 𝜋 + ⁢𝑍 𝑐 ⁢(3900) − + c.c. → 𝜋 + ⁢𝜋 − ⁢𝐽/𝜓, 𝑓 0 ⁡(980)⁢(→ 𝜋 + ⁢𝜋 − )⁢𝐽/𝜓, and (𝜋 + ⁢𝜋 − ) S−wave⁢ 𝐽/𝜓 are measured for the first time. The mass and width of the 𝑍 𝑐 ⁢(3900) ± are determined to be 3884.6 ± 0.7 ± 3.3 MeV/𝑐 2 and 37.2 ± 1.3 ± 6.6 MeV, respectively. The first errors are statistical and the second systematic. The final state (𝜋 + ⁢𝜋 − ) S−wave ⁢𝐽/𝜓 dominates the process 𝑒 + ⁢𝑒 − → 𝜋 + ⁢𝜋 − ⁢𝐽/𝜓. By analyzing the cross sections of 𝜋 ±⁢ 𝑍 𝑐 ⁢(3900) ∓ and 𝑓 0 ⁡(980)⁢𝐽/𝜓, 𝑌⁡(4220) has been observed. Its mass and width are determined to be 4225.7 ± 4.1 ± 3.4 MeV/𝑐 2 and 57.5 ± 9.4 ± 12.1 MeV, respectively.

lepton colliders↗
DOE OSTI2013

Study of exclusive B → X u ℓ ν decays and extraction of | V u b | using full reconstruction tagging at the Belle experiment

Here, we report the results of a study of the exclusive semileptonic decays B - → π 0 ℓ - ν ¯ ℓ , B ¯ 0 → π + ℓ - ν ¯ ℓ , B - → ρ 0 ℓ - ν ¯ ℓ , B ¯ 0 → ρ + ℓ - ν ¯ ℓ and B - → ω ℓ - ν ¯ ℓ , where ℓ represents an electron or a muon. The events are tagged by fully reconstructing a second B meson in the event in a hadronic decay mode. The measured branching fractions are B ( B - → π 0 ℓ - ν ¯ ℓ ) = ( 0.80 ± 0.08 ± 0.04 ) × 10 - 4 , B ( B ¯ 0 → π + ℓ - ν ¯ ℓ ) = ( 1.49 ± 0.09 ± 0.07 ) × 10 - 4 , B ( B - → ρ 0 ℓ - ν ¯ ℓ ) = ( 1.83 ± 0.10 ± 0.10 ) × 10 - 4 , B ( B ¯ 0 → ρ + ℓ - ν ¯ ℓ ) = ( 3.22 ± 0.27 ± 0.24 ) × 10 - 4 , and B ( B - → ω ℓ - ν ¯ ℓ ) = ( 1.07 ± 0.16 ± 0.07 ) × 10 - 4 , where the first error is statistical and the second one is systematic. The obtained branching fractions are inclusive of soft photon emission. Furthermore, we determine the branching fractions as a function of the 4-momentum transfer squared to the leptonic system q 2 = ( p ℓ + p ν ) 2 , where p ℓ and p ν are the lepton and neutrino 4-momenta, respectively. Using the pion modes, a recent light cone sum rule calculation, lattice QCD results and a model-independent description of the hadronic form factor, a value of the Cabibbo-Kobayashi-Maskawa matrix element | V u b | = ( 3.52 ± 0.29 ) × 10 - 3 is extracted. A structure in the two-pion invariant mass distribution near 1.3 GeV / c 2 , which might be dominated by the decay B - → f 2 ( 1270 ) ℓ - ν ¯ ℓ , f 2 → π + π - , is seen. These results are obtained from a 711 fb - 1 data sample that contains 772 × 10 6 B B ¯ pairs, collected near the Υ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Measurement of D 0 - D ¯ 0 mixing and search for indirect C P violation using D 0 → K S 0 π + π - decays

Here, we report a measurement of D 0 - D ¯ 0 mixing parameters and a search for indirect C P violation through a time-dependent amplitude analysis of D 0 → K S 0 π + π - decays. The results are based on 921 fb - 1 of data accumulated with the Belle detector at the KEKB asymmetric-energy e + e - collider. Assuming C P conservation, we measure the mixing parameters x = ( 0.56 ± 0.19 - 0.09 - 0.09 + 0.03 + 0.06 ) % and y = ( 0.30 ± 0.15 - 0.05 - 0.06 + 0.04 + 0.03 ) % , where the errors are statistical, experimental systematic, and systematic due to the amplitude model, respectively. Lastly, with C P violation allowed, the parameters | q / p | = 0.90 - 0.15 - 0.04 - 0.05 + 0.16 + 0.05 + 0.06 and arg ( q / p ) = ( - 6 ± 11 ± 3 - 4 + 3 ) ° are found to be consistent with conservation of C P symmetry in mixing and in the interference between mixing and decay, respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

$B \to \pi \ell \nu$ and $B_s \to K \ell \nu$ form factors and $|V_{ub}|$ from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

We calculate the form factors for B → πℓν and B s → Kℓν decay in dynamical lattice quantum chromodynamics (QCD) using domain-wall light quarks and relativistic b-quarks. We use the (2+1)-flavor gauge-field ensembles generated by the RBC and UKQCD collaborations with the domain-wall fermion action and Iwasaki gauge action. For the b-quarks we use the anisotropic clover action with a relativistic heavy-quark interpretation. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as M π ≈ 290 MeV. We simultaneously extrapolate our numerical results to the physical light-quark masses and to the continuum and interpolate in the pion/kaon energy using SU(2) “hard-pion” chiral perturbation theory for heavy-light meson form factors. We provide complete systematic error budgets for the vector and scalar form factors f + (q 2 ) and f 0 (q 2 ) for both B → πℓν and B s → Kℓν at three momenta that span the q 2 range accessible in our numerical simulations. Next we extrapolate these results to q 2 = 0 using a model-independent z-parametrization based on analyticity and unitarity. We present our final results for f + (q 2 ) and f 0 (q 2 )as the coefficients of the series in z and the matrix of correlations between them; this provides a parametrization of the form factors valid over the entire allowed kinematic range. Our results agree with other three-flavor lattice-QCD determinations using staggered light quarks, and have comparable precision, thereby providing important independent cross-checks. Both B → πℓν and B s → Kℓν decays enable determinations of the Cabibbo-Kobayashi-Maskawa matrix element |V ub |. Furthermore, we perform a combined z-fit of our numerical B → πℓν form-factor data with the experimental measurements of the branching fraction from BABAR and Belle leaving the relative normalization as a free parameter; we obtain |V ub | = 3.61(32)×10 -3 , where the error includes statistical and all systematic uncertainties. The same approach can be applied to the decay B s → Kℓν to provide an alternative determination of |V ub | once the process has been measured experimentally. In anticipation of future experimental measurements, we make predictions for B → πℓν and B s → Kℓν differential branching fractions and forward-backward asymmetries in the Standard Model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Measurements of B → D ¯ D s 0 * + ( 2317 ) decay rates and a search for isospin partners of the D s 0 * + ( 2317 )

In this work, we report improved measurements of the product branching fractions B ( B + → D ¯ 0 D s 0 * + ( 2317 ) ) × B ( D s 0 * + ( 2317 ) → D s + π 0 ) = ( 8. 0 - 1.2 + 1.3 ± 1.1 ± 0.4 ) × 1 0 - 4 and B ( B 0 → D - D s 0 * + ( 2317 ) ) × B ( D s 0 * + ( 2317 ) → D s + π 0 ) = ( 10. 2 - 1.2 + 1.3 ± 1.0 ± 0.4 ) × 1 0 - 4 , where the first errors are statistical, the second are systematic and the third are from D and D s + branching fractions. In addition, we report negative results from a search for hypothesized neutral ( z 0 ) and doubly charged ( z + + ) isospin partners of the D s 0 * + ( 2317 ) and provide upper limits on the product branching fractions B ( B 0 → D 0 z 0 ) × B ( z 0 → D s + π - ) and B ( B + → D - z + + ) × B ( z + + → D s + π + ) that are more than an order of magnitude smaller than theoretical expectations for the hypotheses that the D s 0 * + ( 2317 ) is a member of an isospin triplet. The analysis uses a 711 fb - 1 data sample containing 772 million B B ¯ -meson pairs collected at the Υ ( 4 S ) resonance in the Belle detector at the KEKB collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Measurement of e + e - → π + π - ψ ( 2 S ) via initial state radiation at Belle

We report here measurement of the cross section of e + e - → π + π - ψ ( 2 S ) between 4.0 and 5.5 GeV, based on an analysis of initial state radiation events in a 980 fb - 1 data sample recorded with the Belle detector. The properties of the Y ( 4360 ) and Y ( 4660 ) states are determined. Fitting the mass spectrum of π + π - ψ ( 2 S ) with two coherent Breit-Wigner functions, we discover two solutions with identical mass and width but different couplings to electron-positron pairs: M Y ( 4360 ) = ( 4347 ± 6 ± 3 ) MeV / c 2 , Γ Y ( 4360 ) = ( 103 ± 9 ± 5 ) MeV , M Y ( 4660 ) = ( 4652 ± 10 ± 8 ) MeV / c 2 , Γ Y ( 4660 ) = ( 68 ± 11 ± 1 ) MeV ; and B [ Y ( 4360 ) → π + π - ψ ( 2 S ) ] · Γ Y ( 4360 ) e + e - = ( 10.9 ± 0.6 ± 0.7 ) eV and B [ Y ( 4660 ) → π + π - ψ ( 2 S ) ] · Γ Y ( 4660 ) e + e - = ( 8.1 ± 1.1 ± 0.5 ) eV for one solution; or B [ Y ( 4360 ) → π + π - ψ ( 2 S ) ] · Γ Y ( 4360 ) e + e - = ( 9.2 ± 0.6 ± 0.6 ) eV and B [ Y ( 4660 ) → π + π = ψ ( 2 S ) ] · Γ Y ( 4660 ) e + e - = ( 2.0 ± 0.3 ± 0.2 ) eV for the other. Here, the first errors are statistical and the second systematic. Evidence for a charged charmoniumlike structure at 4.05 GeV / c 2 is observed in the π ± ψ ( 2 S ) intermediate state in the Y ( 4360 ) decays. decays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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 OSTI2015

Standard Model Prediction for Direct C P Violation in K → π π Decay

In this paper, we report the first lattice QCD calculation of the complex kaon decay amplitude A 0 with physical kinematics, using a 32 3 x 64 lattice volume and a single lattice spacing a, with 1/a = 1.3784(68) GeV. We find Re(A 0 ) = 4.66(1.00)(1.26) x 10 -7 GeV and Im(A 0 ) = -1.90(1.23)(1.08) x 10 -11 GeV, where the first error is statistical and the second systematic. The first value is in approximate agreement with the experimental result: Re(A 0 ) = 3.3201(18) x 10 -7 GeV, while the second can be used to compute the direct CP-violating ratio Re(ϵ'/ϵ) = 1.38(5.15)(4.59) x 10 -4 , which is 2.1σ below the experimental value 16.6(2.3) x 10 -4 . Finally, the real part of A 0 is CP conserving and serves as a test of our method while the result for Re(ϵ'/ϵ) provides a new test of the standard model theory of CP violation, one which can be made more accurate with increasing computer capability.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Pinning Susceptibility: The Effect of Dilute, Quenched Disorder on Jamming

Here, we study the effect of dilute pinning on the jamming transition. Pinning reduces the average contact number needed to jam unpinned particles and shifts the jamming threshold to lower densities, leading to a pinning susceptibility, χ p . Our main results are that this susceptibility obeys scaling form and diverges in the thermodynamic limit as χ p ∝ | φ - φ c ∞ | - γ p where φ c ∞ is the jamming threshold in the absence of pins. Finite-size scaling arguments yield these values with associated statistical (systematic) errors γ p = 1.018 ± 0.026 ( 0.291 ) in d = 2 and γ p = 1.534 ± 0.120 ( 0.822 ) in d = 3 . Logarithmic corrections raise the exponent in d = 2 to close to the d = 3 value, while the systematic errors are very large.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Optimal Power Flow With State Estimation in the Loop for Distribution Networks

Here in this article, we propose a framework for running optimal control-estimation synthesis in distribution networks. Our approach combines a primal-dual gradient-based optimal power flow solver with a state estimation feedback loop based on a limited set of sensors for system monitoring, instead of assuming exact knowledge of all states. The estimation algorithm reduces uncertainty on unmeasured grid states based on certain online state measurements and noisy "pseudomeasurements." We analyze the convergence of the proposed algorithm and quantify the statistical estimation errors based on a weighted least-squares estimator. The numerical results on a 4521-node network demonstrate that this approach can scale to extremely large networks and provide robustness to both large pseudomeasurement variability and inherent sensor measurement noise.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Idealized simulation study of the relationship of disdrometer sampling statistics with the precision of precipitation rate measurement

Due to the discretized nature of rain, the measurement of a continuous precipitation rate by disdrometers is subject to statistical sampling errors. Here, Monte Carlo simulations are employed to obtain the precision of rain detection and rate as a function of disdrometer collection area and compared with World Meteorological Organization guidelines for a 1 min sample interval and 95 % probability. To meet these requirements, simulations suggest that measurements of light rain with rain rates R ≤ 0.50 mm h-1 require a collection area of at least 6 cm × 6 cm, and for R = 1 mm h -1 , the minimum collection area is 13 cm × 13 cm. For R = 0.01 mm h -1 , a collection area of 2 cm × 2 cm is sufficient to detect a single drop. Simulations are compared with field measurements using a new hotplate device, the Differential Emissivity Imaging Disdrometer. The field results suggest an even larger plate may be required to meet the stated accuracy, likely in part due to non-Poissonian hydrometeor clustering.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Global sensitivity analysis, probabilistic calibration, and predictive assessment for the data assimilation linked ecosystem carbon model

In this paper we propose a probabilistic framework for an uncertainty quantification (UQ) study of a carbon cycle model and focus on the comparison between steady-state and transient simulation setups. A global sensitivity analysis (GSA) study indicates the parameters and parameter couplings that are important at different times of the year for quantities of interest (QoIs) obtained with the data assimilation linked ecosystem carbon (DALEC) model. We then employ a Bayesian approach and a statistical model error term to calibrate the parameters of DALEC using net ecosystem exchange (NEE) observations at the Harvard Forest site. The calibration results are employed in the second part of the paper to assess the predictive skill of the model via posterior predictive checks.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Measurement of the branching fractions of radiative leptonic τ decays τ → ℓγν anti-ν (ℓ=e,μ) at BABAR

We perform a measurement of the branching fractions for τ → ℓγν anti ν, (ℓ = e, μ) decays for a minimum photon energy of 10 MeV in the τ rest frame using 430 fb -1 of e + e - collisions collected at the center-of-mass energy of the Υ(4S) resonance with the BABAR detector at the PEP-II storage rings. We find B(τ → μγνν) = (3.69±0.03±0.10)×10 3 and B(τ → eγνν) = (1.847 ± 0.015 ± 0.052) × 10 -2 where the first quoted error is statistical and the second is systematic. These results represent a substantial improvement with respect to existing measurements for both channels.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Precise determination of the CKM matrix element $\left| V_{cb}\right|$ with $\bar B^0 \to D^{*\,+} \, \ell^- \, \bar ν_\ell$ decays with hadronic tagging at Belle

The precise determination of the CKM matrix element $\left| V_{cb}\right|$ is important for carrying out tests of the flavour sector of the Standard Model. In this article we present a preliminary analysis of the $\bar B^0 \to D^{*\,+} \, \ell^- \, \bar \nu_\ell$ decay mode and its charge conjugate, selected in events that contain a fully reconstructed $B$-meson, using 772 million $e^+ \, e^- \to \Upsilon(4S) \to B \bar B$ events recorded by the Belle detector at KEKB. Unfolded differential decay rates of four kinematic variables fully describing the $\bar B^0 \to D^{*\,+} \, \ell^- \, \bar \nu_\ell$ decay in the $B$-meson rest frame are presented. We measure the total branching fraction $\mathcal{B}( \bar B^0 \to D^{*\,+} \, \ell^- \, \bar \nu_\ell ) = \left(4.95 \pm 0.11 \pm 0.22 \right) \times 10^{-2}$, where the errors are statistical and systematic respectively. The value of $\left|V_{cb} \right|$ is determined to be $\left( 37.4 \pm 1.3 \right) \times 10^{-3}$. Both results are in good agreement with current world averages.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗