排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
Schumm BA Koetke DS Adolphsen CE 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 Fujino D 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 Hildreth MD Himel T Hinshaw DA 《Physical review D: Particles and fields》1992,46(1):453-456
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Prakhov S Tippens WB Allgower C Bekrenev V Berger E Briscoe WJ Clajus M Comfort JR Craig K Grosnick D Huber GM Isenhower D Knecht N Koetke D Koulbardis A Kozlenko N Kruglov S Kycia T Lolos GJ Lopatin I Manley DM Marusic A Manweiler R McDonald S Nefkens BM Olmsted J 《Physical review letters》2000,84(21):4802-4805
We report the first determination of the upper limit for the branching ratio of the CP forbidden decay eta-->4pi(0). No events were observed in a sample of 3.0x10(7) eta decays. The experiment was performed with the Crystal Ball multiphoton spectrometer installed in a separated pi(-) beam at the AGS (Alternating Gradient Synchrotron). At the 90% confidence limit, B(eta-->4pi(0))=6. 9x10(-7). 相似文献
3.
Detailed spectra of the excited-state absorption and the stimulated-emission cross-sections of Er3+ -doped Y3Al5O12, YAlO3, LiYF4, and KYF4 crystals are analyzed in the infrared wavelength regions from 700 to 2100 nm. The spectra were measured with a pump and probe technique employing a double modulation scheme. For Er (2%): Y3Al5O12 also the stimulated emission at 3 µm and the reabsorption due to excited-state absorption from the lower laser level are investigated. 相似文献
4.
Craig K Comfort JR Allgower CE Bekrenev V Berger E Briscoe WJ Clajus M Draper B Grosnick D Isenhower D Knecht N Koetke D Koulbardis A Kozlenko N Kruglov S Lolos GJ Lopatin I Manley DM Manweiler R Marusić A McDonald S Nefkens BM Olmsted J Papandreou Z Peaslee D Phaisangittisakul N Prakhov S Price JW Pulver M Ramirez AF Sadler ME Shafi A Spinka H Stanislaus S Starostin A Supek I Staudenmaier HM Tippens WB;Crystal Ball Collaboration 《Physical review letters》2003,91(10):102301
Data are presented for the reaction pi(-)p-->pi(0)pi(0)n in the range from threshold to p(pi(-))=750 MeV/c. The systematics of the data and multipole analyses are examined for sensitivity to a f(0)(600) ("sigma") meson. A one-pion-exchange mechanism is found to be very weak, or absent. The reaction appears to become dominated by sequential pi(0) decays through the Delta(1232) resonance as the beam momentum increases, along with substantial interference effects from several competing mechanisms. 相似文献
5.
Musser JR Bayes R Davydov YI Depommier P Doornbos J Faszer W Gagliardi CA Gaponenko A Gill DR Green P Gumplinger P Hasinoff MD Henderson RS Hu J Jamieson B Kitching P Koetke DD Krushinsky AA Lachin YY Macdonald JA MacDonald RP Marshall GM Mathie EL Miasoedov LV Mischke RE Nord PM Olchanski K Olin A Openshaw R Porcelli TA Poutissou JM Poutissou R Quraan MA Rodning NL Selivanov V Sheffer G Shin B Sobratee F Stanislaus TD Tacik R Torokhov VD Tribble RE Vasiliev MA Wright DH;TWIST Collaboration 《Physical review letters》2005,94(10):101805
The TWIST Collaboration has measured the Michel parameter rho in normal muon decay, mu(+)--> e(+)nu(e)nu (mu). In the standard model, rho = 3/4. Deviations from this value imply mixing of left- and right-handed muon and electron couplings. We find rho=0.750 80+/-0.000 32(stat) +/- 0.000 97(syst) +/- 0.000 23, where the last uncertainty represents the dependence of rho on the Michel parameter eta. This result sets new limits on the W(L)-W(R) mixing angle in left-right symmetric models. 相似文献
6.
Nefkens BM Prakhov S Gårdestig A Allgower CE Bekrenev V Briscoe WJ Clajus M Comfort JR Craig K Grosnick D Isenhower D Knecht N Koetke D Koulbardis A Kozlenko N Kruglov S Lolos G Lopatin I Manley DM Manweiler R Marusić A McDonald S Olmsted J Papandreou Z Peaslee D Phaisangittisakul N Price JW Ramirez AF Sadler M Shafi A Spinka H Stanislaus TD Starostin A Staudenmaier HM Supek I Tippens WB;Crystal Ball Collaboration 《Physical review letters》2005,94(4):041601
We report on the first determination of upper limits on the branching ratio (BR) of eta decay to pi0pi0gamma and to pi0pi0pi0gamma. Both decay modes are strictly forbidden by charge conjugation (C) invariance. Using the Crystal Ball multiphoton detector, we obtained BR(eta-->pi0pi0gamma)<5 x 10(-4) at the 90% confidence level, in support of C invariance of isoscalar electromagnetic interactions of the light quarks. We have also measured BR(eta-->pi0pi0pi0gamma)<6 x 10(-5) at the 90% confidence level, in support of C invariance of isovector electromagnetic interactions. 相似文献
7.
Brown CN Awes TC Beddo ME Brooks ML Bush JD Carey TA Chang TH Cooper WE Gagliardi CA Garvey GT Geesaman DF Hawker EA He XC Isenhower LD Kaplan DM Kaufman SB Kirk PN Koetke DD Kyle G Lee DM Lee WM Leitch MJ Makins N McGaughey PL Moss JM Mueller BA Nord PM Papavassiliou V Park BK Peng JC Petitt G Reimer PE Sadler ME Sondheim WE Stankus PW Thompson TN Towell RS Tribble RE Vasiliev MA Webb JC Willis JL Wise DK Young GR;FNAL E/NuSea Collaboration 《Physical review letters》2001,86(12):2529-2532
We present a measurement of the polarization observed for bottomonium states produced in p-Cu collisions at square root of s = 38.8 GeV. The angular distribution of the decay dimuons of the Upsilon(1S) state shows no polarization at small values of the fractional longitudinal momentum x(F) and transverse momentum p(T) but significant positive transverse production polarization for either p(T)>1.8 GeV/c or for x(F)>0.35. The Upsilon(2S+3S) (unresolved) states show a large transverse production polarization at all values of x(F) and p(T) measured. These observations challenge NRQCD calculations of the polarization expected in the hadronic production of bottomonium states. 相似文献
8.
N. G. Kozlenko V. V. Abaev V. S. Bekrenev S. P. Kruglov A. A. Koulbardis I. V. Lopatin A. B. Starostin B. Draper S. Hayden J. Huddleston D. Isenhower C. Robinson M. Sadler C. Allgower R. Cadman H. Spinka J. Comfort K. Craig A. Ramirez T. Kycia M. Clajus A. Marusic S. McDonald B. M. K. Nefkens N. Phaisangittisakul S. Prakhov J. W. Price W. B. Tippens J. Peterson W. J. Briscoe A. Shafi I. I. Strakovsky H. Staudenmaier D. M. Manley J. Olmsted D. Peaslee N. Knecht G. Lolos Z. Papandreou I. Supek I. Slaus A. Gibson D. Grosnic D. Koetke R. Manweiler S. Stanislaus 《Physics of Atomic Nuclei》2003,66(1):110-113
The first results obtained in 1998 by the Crystal Ball collaboration from a measurement of the total and differential cross sections for the reaction π ? p → ηn are presented. These new experimental results for the total cross sections are compared with the predictions of the K-matrix model for pion-nucleon scattering. The angular distribution at momenta near the reaction threshold (685 MeV/c) is determined by the S-wave contribution. The P-wave contribution begins to manifest itself from a momentum of 720 MeV/c. 相似文献
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Zhu LY Reimer PE Mueller BA Awes TC Brooks ML Brown CN Bush JD Carey TA Chang TH Cooper WE Gagliardi CA Garvey GT Geesaman DF Hawker EA He XC Howell DE Isenhower LD Kaplan DM Kaufman SB Klinksiek SA Koetke DD Lee DM Lee WM Leitch MJ Makins N McGaughey PL Moss JM Nord PM Papavassiliou V Park BK Petitt G Peng JC Sadler ME Sondheim WE Stankus PW Thompson TN Towell RS Tribble RE Vasiliev MA Webb JC Willis JL Winter P Wise DK Yin Y Young GR;FNAL E/NuSea Collaboration 《Physical review letters》2008,100(6):062301
We report a high statistics measurement of Upsilon production with an 800 GeV/c proton beam on hydrogen and deuterium targets. The dominance of the gluon-gluon fusion process for Upsilon production at this energy implies that the cross section ratio, sigma(p+d-->Upsilon)/2sigma(p+p-->Upsilon), is sensitive to the gluon content in the neutron relative to that in the proton. Over the kinematic region 0相似文献