共查询到20条相似文献,搜索用时 15 毫秒
1.
《Zeitschrift fur Physik C Particles and Fields》1997,76(3):387-400
Using approximately 4.3 million hadronic Z0 decays collected with the OPAL detector at LEP between 1990 and 1995, we measure the branching fractions of the Z0 into up-type and down-type light quarks, Rq, and the forwardbackward asymmetries, AFB(q), using high-momentum stable particles as a tag. Adopting a method that employs double tagged events to determine the flavour tagging efficiencies, and assuming the flavour independence of strong interactions and SU(2) isospin symmetry, we measure: 相似文献
2.
V. A. Saleev 《Russian Physics Journal》1999,42(2):203-213
Predictions are made within the scope of perturbative quantum chromodynamics and the nonrelativistic two-quark baryon model
of the magnitude and dependence uponz (the fraction of the momentum of the heavy quark carried off by the baryon) of the longitudinal spin asymmetry parameterA
RL
in the direct creation of Λ
b
and Λ
c
baryons in theZ
0-boson channel in the LEPe
+
e
− collider. An estimate is found for the value of
in the cascade production of Λ
b
baryons.
Samara State University, Samara. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 42, No. 2, pp. 66–75,
February, 1999. 相似文献
3.
4.
Effect of Carrier Differences on Spin Polarized Injection into Organic and Inorganic Semiconductors 下载免费PDF全文
Spin polarized injection into organic and inorganic semiconductors are studied theoretically from the spin diffusion theory and Ohm's law, and the emphases are placed on the effect of the carrier differences on the current spin polarization. The mobility and the spin-flip time of carriers in organic and inorganic semiconductors are different. From the calculation, it is found that current spin polarization at a ferromagnetic/organic interface is higher than that at a ferromagnetic/inorganic interface because of different carriers in them. Effects of the conductivity matching, the spin dependent interracial resistances, and the bulk spin polarization of the ferromagnetic layer on the spin polarized injection are also discussed. 相似文献
5.
Ranajeet Ghose Kai Huang James H Prestegard 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,135(2):487-499
We present a simple method for extracting interference effects between chemical shift anisotropy (CSA) and dipolar coupling from spin relaxation measurements in macromolecules, and we apply this method to extracting cross-correlation rates involving interference of amide15N CSA and15N–1H dipolar coupling and interference of carbonyl13C′ CSA and15N–13C′ dipolar coupling, in a small protein. A theoretical basis for the interpretation of these rates is presented. While it proves difficult to quantitatively separate the structural and dynamic contributions to these cross-correlation rates in the presence of anisotropic overall tumbling and a nonaxially symmetric chemical shift tensor, some useful qualitative correlations of data with protein structure can be seen when simplifying assumptions are made. 相似文献
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7.
Abe K Abt I Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Battiston R Bazarko AO Bean A Belcinski RJ Ben-David R Benvenuti AC Biasini M Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Carr J Cassell R Castaldi R Castro A Cavalli-Sforza M Chadwick GB Chen L Church E Claus R Cohn HO Coller JA Cook V Cotton R Cowan RF 《Physical review letters》1994,72(20):3145-3149
8.
Abe F Amidei D Apollinari G Atac M Auchincloss P Baden AR Bamberger A Barbaro-Galtieri A Barnes VE Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Bensinger J Beretvas A Berge JP Bertolucci S Bhadra S Binkley M Blair R Blocker C Booth AW Brandenburg G Brown D Buckley E Byon A Byrum KL Campagnari C Campbell M Carey R Carithers W Carlsmith D Carroll JT Cashmore R Cervelli F Chadwick K Chiarelli G Chinowsky W Cihangir S Clark AG Connor D Contreras M Cooper J Cordelli M Crane D Curatolo M 《Physical review letters》1989,63(7):720-723
9.
Aubert B Bona M Boutigny D Karyotakis Y Lees JP Poireau V Prudent X Tisserand V Zghiche A Garra Tico J Grauges E Lopez L Palano A Eigen G Ofte I Stugu B Sun L Abrams GS Battaglia M Brown DN Button-Shafer J Cahn RN Groysman Y Jacobsen RG Kadyk JA Kerth LT Kolomensky YG Kukartsev G Lopes Pegna D Lynch G Mir LM Orimoto TJ Pripstein M Roe NA Ronan MT Tackmann K Wenzel WA Del Amo Sanchez P Hawkes CM Watson AT Held T Koch H Lewandowski B Pelizaeus M Schroeder T Steinke M Boyd JT Burke JP 《Physical review letters》2007,99(8):081801
We report a measurement of the time-dependent CP-asymmetry parameters S and C in color-suppressed B{0}-->D{(*)0}h{0} decays, where h{0} is a pi{0}, eta, or omega meson, and the decays to one of the CP eigenstates K+K-, K{S}{0}pi{0}, or K{S}{0}omega. The data sample consists of 383 x 10{6} Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The results are S=-0.56+/-0.23+/-0.05 and C=-0.23+/-0.16+/-0.04, where the first error is statistical and the second is systematic. 相似文献
10.
Jacobsen RG Koetke DS Adolphsen CE Fujino D Schumm BA Wagner SR Alexander JP Averill D Barish BC Barklow T Barnett BA Blockus D Boyarski A Brabson B Breakstone A Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan JM Drell PS Drewer DC Durrett D Elia R Feldman GJ Field RC Ford WT Fordham C Frey R Gan KK Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Hanson G Harr R Harral B Harris FA Hayes K Hearty C Heusch CA 《Physical review letters》1991,67(24):3347-3350
11.
Abe K Abt I Ahn CJ Akagi T Allen NJ Ash WW Aston D Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Daoudi M De Sangro R 《Physical review letters》1995,75(20):3624-3628
12.
Aaltonen T Abulencia A Adelman J Akimoto T Albrow MG Alvarez González B Amerio S Amidei D Anastassov A Annovi A Antos J Apollinari G Apresyan A Arisawa T Artikov A Ashmanskas W Attal A Aurisano A Azfar F Azzi-Bacchetta P Azzurri P Bacchetta N Badgett W Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Bartsch V Bauer G Beauchemin PH Bedeschi F Bednar P Behari S Bellettini G Bellinger J Belloni A Benjamin D Beretvas A Beringer J Berry T Bhatti A Binkley M Bisello D Bizjak I Blair RE Blocker C 《Physical review letters》2008,100(12):121803
We measure the mean lifetime tau=2/(Gamma_{L}+Gamma_{H}) and the decay-width difference DeltaGamma=Gamma_{L}-Gamma_{H} of the light and heavy mass eigenstates of the B_{s}{0} meson, B_{sL}{0} and B_{sH}{0}, in B_{s}{0}-->J/psivarphi decays using 1.7 fb;{-1} of data collected with the CDF II detector at the Fermilab Tevatron pp[over ] collider. Assuming CP conservation, a good approximation for the B_{s}{0} system in the standard model, we obtain DeltaGamma=0.076_{-0.063}{+0.059}(stat)+/-0.006(syst) ps{-1} and tau=1.52+/-0.04(stat)+/-0.02(syst) ps, the most precise measurements to date. Our constraints on the weak phase and DeltaGamma are consistent with CP conservation. 相似文献
13.
14.
《Zeitschrift fur Physik C Particles and Fields》1996,70(2):211-217
CP violation has been observed as a time-dependent rate asymmetry between the decays ${?erline K}^0 ?ghtarrow ?^{0} ?^{0}$ and K0 → π0π{0}, where the neutral kaons are produced with definite and individually known strangeness in ${?r p}p ?ghtarrow{?erline K}^0 K^+?^- $ or p?p → K0 K? π+. A special technique for the data analysis has been developed. The values obtained for ?00 and ¦ η00¦ are in agreement with those of previous measurements of CP violation. 相似文献
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16.
Abe K Abt I Ahn CJ Akagi T Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Dasu S 《Physical review letters》1995,74(15):2895-2899
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18.
R. Barate et al. 《The European Physical Journal C - Particles and Fields》1998,2(2):197-211
Using approximately 4 million hadronic Z decays recorded with the aleph detector from 1991 through 1995, the lifetime of the b baryon is measured with three independent methods. From the impact
parameter distribution of candidate leptons in 1063 events with combinations, the average b baryon lifetime is measured to be ps. From a sample of 193 fully reconstructed candidates correlated with a lepton and a sample of 46 combinations, the lifetime is measured to be ps. The product branching fractions to these final states are % for the first sample and % for the second and third samples combined.
Received: 15 August 1997 / Online publication: March 10, 1998 相似文献
19.
A new method of fluorescence polarization is applied to evaluate the angle of the preferential orientation of Rhodamine 6G (R6G) dye adsorbed in supported thin films of Laponite (Lap) clay. The method is based in the determination of the fluorescence dichroic ratio, obtained from the recorded fluorescence spectra with the detection polarizer horizontally and vertically oriented, as a function of the twisted angle of the film around its vertical axis, keeping the excitation polarizer in a fixed direction. The validity of the method is checked by comparing the experimental results obtained with both vertically and horizontally polarized excitations to that previously provided by absorption spectroscopy with linearly polarized light. A preferential orientation angle with respect to the normal to the clay layer of 62° is derived for R6G monomers adsorbed in Lap films. 相似文献
20.
A. Bartl H. Fraas O. Kittel W. Majerotto 《The European Physical Journal C - Particles and Fields》2004,36(2):233-243
We study CP-sensitive observables in the neutralino production
and the subsequent two-body decays of the neutralino
and of the Z boson
. We identify the CP-odd elements of the Z boson density matrix and propose CP-sensitive triple-product asymmetries. We calculate these observables and the cross sections in the minimal supersymmetric standard model with complex parameters and M
1 for an e
+
e
- linear collider with
GeV and longitudinally polarized beams. We show that the asymmetries can reach
for
and
for
and discuss the feasibility of measuring these asymmetries.Received: 4 February 2004, Revised: 17 May 2004, Published online: 2 July 2004 相似文献