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61.
Dugger M Ball JP Collins P Pasyuk E Ritchie BG Adams G Ambrozewicz P Anciant E Anghinolfi M Asavapibhop B Asryan G Audit G Avakian H Bagdasaryan H Baillie N Baltzell NA Barrow S Batourine V Battaglieri M Beard K Bedlinskiy I Bektasoglu M Bellis M Benmouna N Berman BL Bianchi N Biselli AS Bonner BE Bouchigny S Boiarinov S Bradford R Branford D Briscoe WJ Brooks WK Bültmann S Burkert VD Butuceanu C Calarco JR Careccia SL Carman DS Carnahan B Chen S Cole PL Coleman A Coltharp P Cords D 《Physical review letters》2006,96(6):062001
Differential cross sections for the reaction gamma p --> eta' p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data suggest for the first time the coupling of the eta'N channel to both the S11(1535) and P11(1710) resonances, known to couple strongly to the etaN channel in photoproduction on the proton, and the importance of J = 3/2 resonances in the process. 相似文献
62.
Azeem Mir Farida Tahir Kamaluddin Ahmed 《The European Physical Journal C - Particles and Fields》2010,65(3-4):475-490
We study the decay rate of the process B→Kl + l ? (l=e,μ) and some of its other related observables, like the forward–backward asymmetry (A FB), polarization asymmetry (PA), double branching ratio and CP asymmetry (A CP) in the R-parity violating Minimal Supersymmetric Standard Model ( $\not \!{R}_{p}$ MSSM). We have performed an error analysis of the differential branching fraction, A FB and CP asymmetry. The analysis shows that theoretical results based on $\not \!{R}_{p}$ MSSM as an additional effect are compatible with the standard model. A FB is found to be zero, in agreement with SM. The average A CP is not only found to be significant in comparison with SM, but it is also compatible with the measured value within errors. 相似文献
63.
64.
T. Bouchaour F. Benmouna L. Leclercq B. Ewen X. Coqueret M. Benmouna 《Liquid crystals》2013,40(3):413-420
The experimental equilibrium phase diagram of mixtures of linear poly(n-butyl acrylate) of molecular mass Mw = 112000 g mol-1 and the low molecular mass LC mixture E7 has been established using polarized optical microscopy and light scattering techniques. The diagram is found to be reminiscent of an upper critical solution temperature system. Two independent series of samples with the same composition were studied, yielding consistent results. A region of nematic and isotropic coexisting phases and a region of a single isotropic phase were identified in the composition-temperature phase diagram. The results were analysed within a theoretical model combining the Flory-Huggins lattice theory for isotropic mixing and the Maier-Saupe theory for nematic ordering. Interestingly, no region of isotropic coexisting phases was observed in our experiments. This is probably due to the fact that the nematic interaction overwhelms the isotropic interaction in the region where (I + I) coexisting phases could appear. A preferential solubility of certain constituents of the LC mixture in the polymer could possibly be a reason for this behaviour. 相似文献
65.
Aidoudi FH Byrne PJ Allan PK Teat SJ Lightfoot P Morris RE 《Dalton transactions (Cambridge, England : 2003)》2011,40(16):4324-4331
An exploratory study of the synthesis of vanadium (oxy)fluorides (VOFs) using ionic liquids (ILs) and deep eutectic mixtures (DESs) as a solvent yielded 10 different materials. The previously reported chain type: (NH(4))(2)VF(5) (1), (NH(4))(2)VOF(4) (2), NH(4)VO(3) (3) and (H(2)NH(2)(CH(2))(2)NH(2))VF(5) (9) have been successfully produced for the first time using ILs as the reaction media. The monomeric (HNH(2)CH(3))(2)VOF(4)(H(2)O) (4), the dimer (HNH(2)CH(3))(4)V(2)O(2)F(8) (5) and the 1D chains (HNH(2)CH(3))(2)VF(5) (6), (H(2)O)(2)VF(3) (7), α-(H(2)NH(2)(CH(2))(2)NH(2))VOF(4) (8) and β-(H(2)NH(2)(CH(2))(2)NH(2))VOF(4) (10) are novel materials. Template control has also been achieved by the selective choice of ILs or the appropriate deep eutectic mixture, where the expected template is delivered to the reaction by the partial breakdown of the urea derivative portion of the DES. 相似文献
66.
Farida Kachapova Ilias Kachapov 《International Journal of Mathematical Education in Science & Technology》2013,44(3):418-427
This note introduces a monotony coefficient as a new measure of the monotone dependence in a two-dimensional sample. Some properties of this measure are derived. In particular, it is shown that the absolute value of the monotony coefficient for a two-dimensional sample is between |r| and 1, where r is the Pearson's correlation coefficient for the sample; that the monotony coefficient equals 1 for any monotone increasing sample and equals ?1 for any monotone decreasing sample. This article contains a few examples demonstrating that the monotony coefficient is a more accurate measure of the degree of monotone dependence for a non-linear relationship than the Pearson's, Spearman's and Kendall's correlation coefficients. The monotony coefficient is a tool that can be applied to samples in order to find dependencies between random variables; it is especially useful in finding couples of dependent variables in a big dataset of many variables. Undergraduate students in mathematics and science would benefit from learning and applying this measure of monotone dependence. 相似文献
67.
Battaglieri M De Vita R Kubarovsky V Guo L Mutchler GS Stoler P Weygand DP Ambrozewicz P Anghinolfi M Asryan G Avakian H Bagdasaryan H Baillie N Ball JP Baltzell NA Batourine V Bedlinskiy I Bellis M Benmouna N Berman BL Biselli AS Bouchigny S Boiarinov S Bradford R Branford D Briscoe WJ Brooks WK Bültmann S Burkert VD Butuceanu C Calarco JR Careccia SL Carman DS Chen S Clinton E Cole PL Coltharp P Crabb D Crannell H Cummings JP Dale D De Sanctis E Degtyarenko PV Deur A Dharmawardane KV 《Physical review letters》2006,96(4):042001
The exclusive reaction gammap-->K0K+n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of the exotic baryon Theta+ (1540)-->nK+. The decay to nK+requires the assignment of strangeness S=+1 to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70 pb-1. No evidence for the Theta+ pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and nK+ mass. The 95% C.L. upper limit on the total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb. 相似文献
68.
Ungaro M Stoler P Aznauryan I Burkert VD Joo K Smith LC Adams G Amarian M Ambrozewicz P Anghinolfi M Asryan G Audit G Avakian H Bagdasaryan H Ball JP Baltzell NA Barrow S Batourine V Battaglieri M Bedliski I Bektasoglu M Bellis M Benmouna N Berman BL Biselli AS Bonner BE Bouchigny S Boiarinov S Bradford R Branford D Briscoe WJ Brooks WK Bültmann S Butuceanu C Calarco JR Careccia SL Carman DS Cazes A Chen S Cole PL Coltharp P Cords D Corvisiero P Crabb D Cummings JP Sanctis ED Devita R 《Physical review letters》2006,97(11):112003
We report a new measurement of the exclusive electroproduction reaction gamma(*)p-->pi(0)p to explore the evolution from soft nonperturbative physics to hard processes via the Q(2) dependence of the magnetic (M(1+)), electric (E(1+)), and scalar (S(1+)) multipoles in the N-->Delta transition. 9000 differential cross section data points cover W from threshold to 1.4 GeV/c(2), 4pi center-of-mass solid angle, and Q(2) from 3 to 6 GeV(2)/c(2), the highest yet achieved. It is found that the magnetic form factor G(M)(*) decreases with Q(2) more steeply than the proton magnetic form factor, the ratio E(1+)/M(1+) is small and negative, indicating strong helicity nonconservation, and the ratio S(1+)/M(1+) is negative, while its magnitude increases with Q(2). 相似文献
69.
The structural, elastic, electronic and optical properties of the cubic CaMH3 (M=Ni and Pd) compounds are investigated using first principle calculations based on the density functional theory (DFT) as implemented in the Wien2k code. The calculated lattice constants are found to be in good agreement with the values reported in the previous literature. The analysis of standard enthalpy of formation shows that both CaNiH3 and CaPdH3 are thermodynamically stable. The bulk modulus and cohesive energy values indicate that CaNiH3 is less compressible and more rigid than CaPdH3. The bonding forces between atoms of the studied compounds are mainly ionic and partially covalent. The real and imaginary parts of the dielectric function are used to calculate the optical properties. The partial density of states for the present compounds are used to explain the main peaks of the optical spectra. Beneficial optoelectronic applications are predicted from the analysis of the optical spectra of CaNiH3 and CaPdH3 compounds. 相似文献
70.
Ireland DG McKinnon B Protopopescu D Ambrozewicz P Anghinolfi M Asryan G Avakian H Bagdasaryan H Baillie N Ball JP Baltzell NA Batourine V Battaglieri M Bedlinskiy I Bellis M Benmouna N Berman BL Biselli AS Blaszczyk L Bouchigny S Boiarinov S Bradford R Branford D Briscoe WJ Brooks WK Burkert VD Butuceanu C Calarco JR Careccia SL Carman DS Casey L Chen S Cheng L Cole PL Collins P Coltharp P Crabb D Crede V Dashyan N De Masi R De Vita R De Sanctis E Degtyarenko PV Deur A Dickson R Djalali C 《Physical review letters》2008,100(5):052001
We examine the results of two measurements by the CLAS collaboration, one of which claimed evidence for a Theta(+) pentaquark, while the other found no such evidence. The unique feature of these two experiments was that they were performed with the same experimental setup. Using a Bayesian analysis, we find that the results of the two experiments are in fact compatible with each other, but that the first measurement did not contain sufficient information to determine unambiguously the existence of a Theta(+). Further, we suggest a means by which the existence of a new candidate particle can be tested in a rigorous manner. 相似文献