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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 307 records · Page 17
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DOE OSTI2011

Transition nucleon resonance electrocouplings from CLAS data on {pi}{sup +}{pi}{sup -}p electroproduction off protons

Electrocouplings of excited proton states with masses less than 1.8 GeV were determined for the first time from the CLAS data on {pi}{sup +}{pi}{sup -}p electroproduction at photon virtualities Q{sup 2}<1.5 GeV{sup 2}. Electrocouplings were obtained from a combined fit of all available observables within the framework of a phenomenological reaction model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

A study of mixing properties of a{sub 1}(1260) meson

We develop a practical method to analyze the mixing structure of hadrons consisting of two components of quark composite and hadronic composite by taking the a{sub 1}(1260) meson as an example. We also make reference to the large Nc procedure and its limitation for the classification of such a mixed state.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Analysis of the doubly radiative decays $η^{(')}$ → $π^0γγ$ and $η^{(')}$ → $ηγγ$

We study the doubly radiative decays $η^{(')}$ → $π^0γγ$ and $η^{(')}$ → $ηγγ$ in terms of vector and scalar meson exchange contributions using, respectively, the frameworks of Vector Meson Dominance and the Linear Sigma model. Predictions for the ${m}_{γγ}^{2}$ invariant mass distribution and branching ratios are given, and a discussion of how they compare to experimental data is carried out.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The Charmonium-molecule hybrid structure of the X(3872)

We propose that the X(3872) has the charmonium and the DD*-bar hadronic molecule hybrid structure. We study the structure of the X(3872) using the schematic model with the separable interaction. The strengths of the couplings between the charmonium state and the hadronic molecule states are determined so as to reproduce the observed mass of the the X(3872). The isospin symmetry breaking is introduced by the mass differences of the neutral and charged D mesons. The obtained structure of the X(3872) is about 9% of cc-bar charmonium, 75% of the isoscalar DD*-bar molecule and 16percent; of the isovector DD*-bar molecule which explains observed properties of the X(3872) well.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Measurement of spin-density matrix elements in 𝜙⁡(1020) → 𝐾$^{0}_{𝑆}$⁢𝐾$^{0}_{𝐿}$ photoproduction with a linearly polarized photon beam at 𝐸 𝛾 = 8.2–8.8 GeV

We measure the spin-density matrix elements (SDMEs) for the photoproduction of 𝜙⁡(1020) off of the proton in its decay to 𝐾$^{0}_{𝑆}$⁢𝐾$^{0}_{𝐿}$, using 105 pb −1 of data collected with a linearly polarized photon beam using the GlueX experiment. The SDMEs are measured in nine bins of the squared four-momentum transfer 𝑡 in the range −𝑡=0.15−1.0 GeV 2 , providing the first measurement of their 𝑡 dependence for photon beam energies of 𝐸 𝛾 = 8.2−8.8 GeV. We confirm the dominance of Pomeron exchange in this region and put constraints on the contribution of other Regge exchanges. We also find that helicity amplitudes where the helicity of the photon and 𝜙⁡(1020) differ by two units are negligible.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Electromagnetic production of hyperon resonances

The study of hyperon resonances has entered a new era of precision with advent of high-statistics photoproduction data from the CLAS detector at Jefferson Lab. These data have multi-particle final states, allowing clean identification of exclusive reactions associated with strange mesons and baryons. Examples of physics results are: evidence for isospin interference in the decay of the {Lambda}(1405) resonance; a strong suggestion of meson cloud effects in the structure of the {Sigma}(1385) resonance; data from K* photoproduction that will test the existence of the purported K{sub 0}(800) meson. Properties of other hyperon resonances will also be studied in the near future.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Pion photoproduction in a dynamical coupled-channel model

Pion photoproduction reactions are investigated in a dynamical coupled-channel approach based on the Juelich {pi}N model, which presently includes the hadronic {pi}N and {eta}N stable channels as well as the {pi}{Delta}, {sigma}N and {rho}N effective channels. This model has been quite successful in the description of {pi}N{yields}{pi}N scattering for center-of-mass energies up to 1.9 GeV. The full pion photoproduction amplitude is constructed to satisfy the generalized Ward-Takahashi identity and hence, it is fully gauge invariant. The calculated differential cross sections and photon spin asymmetries up to 1.65 GeV center-of-mass energy for the reactions {gamma}p{yields}{pi}{sup +}n, {gamma}p{yields}{pi}{sup 0}p and {gamma}n{yields}{pi}{sup -}p are in good agreement with the experimental data.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

K*{sup +} Photoproduction at CLAS

The study of hyperon resonances has entered a new era of precision with advent of high-statistics photoproduction data from the CLAS detector at Jefferson Lab and elsewhere. These data have multi-particle final states, allowing clean identification of exclusive reactions associated with strange mesons and baryons. In this paper, cross sections for K* photoproduction are presented that will provide a future test of the existence of the purported K{sub 0}(800) meson via comparison with theoretical models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

NN*(1440) quasi-bound states

Inspired by a recent observation of a narrow resonance-like structure around 2360 MeV in the pn {yields} d{pi}{sup 0}{pi}{sup 0} cross section, we investigate the possibility of forming NN*(1440) quasi-bound state by meson exchange potential. With parameters of the t-channel {pi}, {sigma}, {rho} and {omega} exchanges determined by relevant NN scattering and N*(1440) decay processes, it is found that a NN*(1440) quasi-bound state with the same quantum numbers as the deuteron can be formed with binding energy about 20 MeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Analysis of the decay D{sup 0}{yields}K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0}

We present the results of a Dalitz plot analysis of D{sup 0}{yields}K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0} using the CLEO-c data set of 818 pb{sup -1} of e{sup +}e{sup -} collisions accumulated at {radical}(s)=3.77 GeV. This corresponds to 3x10{sup 6} D{sup 0}D{sup 0} pairs from which we select 1259 tagged candidates with a background of 7.5{+-}0.9 percent. Several models have been explored, all of which include the K{sup *}(892), K{sub 2}{sup *}(1430), K{sup *}(1680), the f{sub 0}(980), and the {sigma}(500). We find that the combined {pi}{sup 0{pi}0} S-wave contribution to our preferred fit is (28.9{+-}6.3{+-}3.1)% of the total decay rate while D{sup 0}{yields}K{sup *}(892){sup 0}{pi}{sup 0} contributes (65.6{+-}5.3{+-}2.5)%. Using three tag modes and correcting for quantum correlations we measure the D{sup 0}{yields}K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0} branching fraction to be (1.058{+-}0.038{+-}0.073)%.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Measurement of Vector Boson Plus $D^{*}(2010)^+$ Meson Production in $\bar{p}p$ Collisions at $\sqrt{s}=1.96\, {\rm TeV}$

Our study of vector boson (V ) production in conjunction with a D*(2010) + meson is presented. Using a data sample correponding to 9.7 fb -1 p of proton-antiproton collisions at center-of-mass energy √s = 1:96 TeV produced by the Fermilab Tevatron, we reconstruct V +D *+ samples with the CDF II detector. The D *+ is fully reconstructed in the D*(2010) + → D 0 (→ K - π + )π + decay mode. This technique is sensitive to the associated production of vector boson plus charm or bottom mesons. We measure the ratio of production cross sections σ(W +D * )/ σ(W) = [1.75±0.13(stat)±0:09(syst)]% and σ(Z +D * )/ σ(Z) = [1:5±0:4(stat)_0:2(syst)]%. Event properties are utilized to determine the fraction of V +D * (2010) + events originating from different production processes. Our results are in agreement with the predictions obtained with the pythia program, limiting possible contribution from non-standard-model physics processes.

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DOE OSTI2016

Scrutinizing a di-photon resonance at the LHC through Moscow zero

The ATLAS and CMS collaborations have recently released their new analyses of the diphoton searches. We look in detail the consequences of their results deriving strong constraints on models where a scalar resonance s decays into two light pseudoscalars which in turn decay into two pairs of collimated photons, mis-identified with two real photons. In our construction, all mass terms are generated dynamically, and only one pair of vector-like fermions generate couplings which will be probed using the upcoming LHC data. Moreover, we show that a stable dark matter candidate, respecting the cosmological constraints, is naturally affordable in the model.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Exclusive electroproduction of the {rho}{sup +} meson on the proton - CLAS

We present preliminary results of the exclusive electroproduction of {rho}{sup +} on the proton at CLAS. We discuss the interpretation of the cross sections in terms of t-channel Reggeon exchanges and in terms of Generalized Parton Distributions (GPDs) formalism.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

B hadrons spectroscopy at the D0 experiment

The latest results on B hadron spectroscopy from the DOe experiment at the Tevatron are presented. The mass measuremen of the B{sub c}{sup -} meson in the B{sub c}{sup -}{yields}J/{psi}{pi}{sup -} decay channel, the observation of excited B{sub s} mesons, the first direct observation of the {Xi}{sub b}{sup -} baryon, and the first observation of the {Omega}{sub b}{sup -} baryon.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

In-medium Properties of {omega} and {eta}' Mesons in Elementary Reactions

We have investigated the in-medium properties of {omega} and eta prime mesons in photoproduction experiments using the Crystal Barrel(CB)/TAPS detector system at the ELSA accelerator facility in Bonn. Different methods to study the in-medium properties of the hadrons are discussed. The lineshape analysis of {omega}-mesons for two energy ranges shows limited sensitivity to in-medium modifications. Recent results on the in-medium width of the eta prime-meson, derived from transparency ratio measurements, are presented. The absorption of the eta prime-meson in nuclear matter is discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Observation of B - →$\bar{p}$ΛD 0 at Belle

We study B- meson decays to $\bar{p}$ΛD (*)0 final states using a sample of 657×10 6 B$\bar{B}$ events collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider. The observed branching fraction for B - →$\bar{p}$ΛD 0 is (1.43$+0.28\atop{-0.25}$±0.18)×10 -5 with a significance of 8.1 standard deviations, where the uncertainties are statistical and systematic, respectively. Most of the signal events have the $\bar{p}$ Λ mass peaking near threshold. No significant signal is observed for $\bar{p}$ΛD (*)0 and the corresponding upper limit on the branching fraction is 4.8×10 -5 at the 90% confidence level.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Dipion invariant mass distribution of the anomalous {Upsilon}(1S){pi}{sup +}{pi}{sup -} and {Upsilon}(2S){pi}{sup +}{pi}{sup -} production near the peak of {Upsilon}(10860)

Considering the defects of the previous work for estimating the anomalous production rates of e{sup +}e{sup -}{yields}{Upsilon}(1S){pi}{sup +}{pi}{sup -}, {Upsilon}(2S){pi}{sup +}{pi}{sup -} near the peak of the {Upsilon}(5S) resonance at {radical}(s)=10.87 GeV [K. F. Chen et al. (Belle Collaboration), Phys. Rev. Lett. 100, 112001 (2008)], we suggest a new scenario where the contributions from the direct dipion transition and the final-state interactions interfere to result in not only the anomalously large production rates, but also line shapes of the differential widths consistent with experimental measurement when assuming the reactions are due to the dipion emission of {Upsilon}(5S). At the end, we raise a new puzzle that the predicted differential width d{Gamma}({Upsilon}(5S){yields}{Upsilon}(2S){pi}{sup +}{pi}{sup -})/dcos{theta} has a discrepant trend from the data while other predictions are well in accord with the data. It should be further clarified by more accurate measurements carried by future experiments.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗