共查询到20条相似文献,搜索用时 31 毫秒
1.
A.E. Asratyan V.Sh. Epstein E.A. Grigoriev N.V. Kalganov V.S. Kaftanov V.D. Khovansky Yu.G. Kornelyuk M.A. Kubantsev I.P. Maksimov A.N. Rozanov M.S. Ryabinin V.M. Serezhin V.V. Shamanov V.G. Shevchenko V.A. Smotryaev I.S. Trostin A.A. Zaytsev S.A. Zeldovich Ya.A. Zudin 《Physics letters. [Part B]》1977,71(2):439-442
A search for dimuons produced in a spark chamber experiment in neutrino and antineutrino beams of the Serpukhov accelerator is reported. The clear dimuon signal has been observed in vN interactions. Rv = N(2ω)/N(1ω)? (6.2 ± 1.7) × 10?3 in the energy interval 7.5 ÷ 30 GeV. From antineutrino data we conclude that in the same energy range . 相似文献
2.
D. Allasia C. Angelini A. Baldini S. Barlag L. Bertanza A. Bigi V. Bisi F. Bobisut T. Bolognese R. Bonarelli E. Calimani R. Casali P. Capiluppi S. Ciampolillo J. Derkaoui E. De Wolf M.L. Faccini-Turleur R. Wigmans 《Nuclear Physics B》1984,239(2):301-310
The total νμ and nucleon charged-current cross sections have been measured in BEBC filled with deuterium and exposed to the wide-band neutrino and antineutrino beams at the CERN-SPS. Assuming a linear energy dependence for the cross sections, σ = aE(?ν, we obtained the coefficients , where the quoted error is mainly systematic. The ratio of the cross sections is .We also determined the ratio of the charged-current cross section for neutrino interactions on neutrons and protons R = σνn/σνp = 2.10 ± 0.08 (statistical) ±0.22 (sysetmatic). The dependence of R on the variables x, y and Eν is discussed. 相似文献
3.
O. Erriquez S. Natali S. Nuzzo A. Pullia F. Romano D.C. Colley G.T. Jones L. Lowe S. ONeale S.J. Sewell G. Bertrand-Coremans H. Mulkens J. Sacton C. Vander Velde-Wilquet J. Wickens V. Brisson P. Petiau T.W. Jones 《Physics letters. [Part B]》1978,77(2):227-232
For e+ energy > 0.3 GeV and 10 GeV < visible energy < 100 GeV we find that: (i) ; (ii) 1.2 ± 0.5 neutral strange particles are produced per μ?e+ event; (iii) the lifetime of possible positron-parent particles is < 3 × 10?10 s (90% C.L.); (iv) the cross section for direct e+ production via the neutral current is < 0.2 times that via the charged current (90% C.L.); (v) the cross section for producing heavy leptons, L+, decaying into e+ … is < 0.7 × 10?3 times that for μ?production, implying M(L+) > 10 GeV. 相似文献
4.
J.G. Rushbrooke R.E. Ansorge C.P. Bust J.R. Carter W.W. Neale C. Moore R. Raja L. Voyvodic R.J. Walker W. Morris B.Y. Oh D.L. Parker G.A. Smith J. Whitmore 《Physics letters. [Part B]》1975,59(3):303-307
New 100 GeV/cp data are used to find moments of the difference between the p and pp topological cross sections. The mean multiplicity for annihilations at 100 GeV/c is estimated to be 9.06 ± 0.56, and the value of the quantity 〈n〉/D to be 2.75 ± 0.33. It is shown that appears at 100 GeV/c to have acquired an asymptotic form, Rn = s?αβn, with α and β constant. 相似文献
5.
Measurements of the microwave spectrum of the C4v molecule IF5 in the excited vibrational states v5(B1) = 1 and v9(E) = 1 are reported for the transitions J4 → 5, 5 → 6, 6 → 7, 8 → 9, and 9 → 10 (27–55 GHz). The Coriolis resonance interaction between these two states is analyzed by diagonalization of Hamiltonian matrices of dimension 3 × (2J + 1) in which all (Δl,Δk) = (±2, ±2)(q+), (±2, ±2)(q?), and (0, ±4)(R6) interactions are included as off-diagonal terms in addition to the v5 = 1 ? v9 = 1, l9 = ±1(R59) Coriolis interaction. In the v9 = 1 state spectra, the l-doubling of the kl = ?1 transitions and splittings of the kl = ?3 transitions and splittings of the kl = +3 transitions, all enhanced by the Coriolis resonance, have been observed and measured. Least-squares refined rovibrational parameters for the v5 = 1 and v9 = 1 states are reported and a preliminary value for the rotational constant C9 has been obtained. 相似文献
6.
New quarks and new flavor-changing neutral currents give multiple lepton plus hadron final states in e+e-, . We observe that (i) e+e- is a favored place to search for their effects through inclusive ratios σ(e+e-+x:σ (μ+μ- +x): σ(e±μ±+x) and same sign leptons e±e±+x, μ±μ±+x,e±μ±+x. Above a new flavor threshold four charged lrpton final states may become important. (ii) Trilepton final states in are not sensitive to the presence of flavor-changing neutral currents. Much more sensitive are the processes are +e-+βand (for charm changing neutral currents) . 相似文献
7.
8.
Yu.B. Bushnin A.F. Dunaitsev R.I. Dzelyadin S.V. Golovkin V.F. Konstantinov V.P. Kubarovsky L.G. Landsberg V.M. Leontiev G.P. Makarov V.A. Mukhin V.G. Rybakov T.I. Petrunina Yu.N. Simonov V.V. Smirnov A.M. Zaitsev A. Zallo 《Physics letters. [Part B]》1976,64(1):102-106
The difference of the cross sections for deep inelastic scattering of muons with average momenta 21 GeV/c with right and left helicity at large angles, i.e., with large momentum transfer, has been measured. No statistically-significant dependence of cross sections on the longitudinal polarization of muons has been found, i.e. no parity-nonconservation effects in deep inelastic μN interaction have been observed. The magnitude of the cross-section asymmetry may be represented as R = β〈Q2〉 = (? 4 ± 6) × 10?3 〈Q2, (GeV/c)2〉. The limitations Go(μ) = (+ 6 ± 10)G have been obtained for the constant Go(μ) of vector-axial interaction (hadron, V-A). 相似文献
9.
We propose an O(18) theory which is perturbatively unifiable and which accounts for the absence of right-handed families in the low-energy world. The theory predicts a fourth left-handed family as well as four right-handed families at energies near the weak scale. It also implies the existence of eight light neutrinos, all of which contribute to the width of the Z0. Cosmological arguments suggest that four of these neutrinos should have masses between 2 and 35 GeV, and that the other four should be much lighter. They also suggest the existence of a doubly charged scalar φ++ and a singly charged scalar φ+. Dramatic signatures include the production of four right-handed charged leptons and eight right-handed quarks, , and e+e? → φ++ + φ??. The lightest right-handed charged quark should be surprinsingly long-lived for a particle of mass ? 100 GeV. 相似文献
10.
F.J. Hasert W. Krenz J. Von Krogh D. Lanske J. Morfin K. Schultze H. Weerts G.H.B. Coremans H. Mulkens J. Sacton W. Van Doninck D.C. Cundy D. Haidt P. Musset A. Norton J.B.M. Pattison F. Romano A. Rousset A.J. Segar 《Physics letters. [Part B]》1975,59(5):485-489
A study is presented of single πo production in neutrino and antineutrino interactions in Gargamelle filled with freon CF3Br. Limits on the neutral to charged current cross-section ratios and are found to be at 68% confidence level. 相似文献
11.
V.V. Abramov A.V. Alekseev B.Yu. Baldin S.I. Bityukov V.Yu. Glebov A.S. Dyshkant V.N. Evdokimov A.N. Krinitsin V.I. Kryshkin N.Yu. Kulman G.I. Lanshchikov V.K. Myalitsyn Yu.M. Melnik A.P. Orlov V.I. Povzun R.M. Sulyaev L.K. Turchanovich Yu.N. Vrazhnov V.V. Zmushko 《Nuclear Physics B》1980,173(2):348-364
The cross sections for π±, K±, p, and production in pp collisions have been measured at transverse momenta from 0.48 up to 2.21 GeV/c at 70 GeV. The data are compared with results obtained at lower and higher proton energies and also with the quantum chromodynamics parton model (QPM) calculations. Common behaviour of the cross sections of the form in the energy range above 200 GeV does not take place at lower energies. Qualitatively QPM fits the data and the best agreement is for π+/π? and K+/π+ ratios. 相似文献
12.
R. Brandelik W. Braunschweig H.-U. Martyn H.G. Sander D. Schmitz W. Sturm W. Wallraff D. Cords R. Felst R. Fries E. Gadermann H. Hultschig P. Joos W. Koch U. Kötz H. Krehbiel D. Kreinick S. Yamada 《Physics letters. [Part B]》1978,73(1):109-114
The cross sections for e+e? → e+(μ+ + non showering track + any photons have been measured for cm energies between 3.1 GeV and 5.2 GeV. We observe τ-pair production below the thresholdfor charm production and determine the τ mass to be 1.807 ± 0.020 GeV from a fit to the energy dependence of the cross section. The ration of the leptonic branching ratios Bμ/Be = 0.92 ± 0.32 is consistent with eμ-universality. The following branching ratios are determined for a V-A coupling: . B(τ → ντ + charged hadron + any photons) = 0.29 ± 0.11, B(τ → ντ + three or more charged hadrons + any photons) = 0.35 ± 0.11. 相似文献
13.
Using a recent theoretical method, the ratio of nuclear matrix elements was determined to be either 20.50+0.35?0.55 or 25.22+0.28?0.17 in the second-forbidden nonunique decay of 8 × 104 y 59Ni. These values of R were obtained from a value of L3/K = 0.008 ± 0.002 found by subtracting the theoretical ratio = 0.113 (based on QPEC = 1070 ± 8 keV) from the total ratio L/K = 0.121 ± 0.002, which was measured with a reactor-produced, doubly-mass-separated 59Ni source introduced as gaseous nickel-ocene, (C5H5)2, into a wall-less, anticoincidence, multiwire proportional counter. The 854–1008 eV L and the 8.33 keV K peaks were measured simultaneously. 相似文献
14.
H. Albrecht R. Childers C.W. Darden G. Drews H. Hasemann W. Schmidt-Parzefall H. Schröder H.D. Schulz F. Selonke E. Steinmann R. Wurth W. Hofmann A. Markees D. Wegener K.R. Schubert J. Stiewe R. Waldi S. Weseler Yu. Zaitsev 《Physics letters. [Part B]》1982,116(5):383-386
The reaction e+e?→ hadrons has been measured in the ? and ?′ region using the DASP detector at the DESY storage ring DORIS. The following final results are obtained: Rhad(9.5 GeV)=3.73±0.16±0.28, Γee(?)=(1.23 ± 0.08 ± 0.12) keV, Bμμ(?)=(3.2±1.3±0.3)%, , and M(?′)?M(?)=(556 ±10) MeV. 相似文献
15.
J. Banaigs J. Berger L. Goldzahl T. Risser L. Vu-Hai M. Cottereau C. Le Brun 《Physics letters. [Part B]》1973,45(4):394-398
The reactions d + p → τ + π0 and d + p → τ + η0 were studied using the missing-mass method for incident deuteron momenta between 2.8 and . The angular distributions show a peak in the forward direction () and are flat in the backward direction. The differential cross sections at for both reactions show a maximum for total center-of-mass energies near 3.46 GeV. 相似文献
16.
W.D. Apel J. Ausländer H. Müller G. Sigurdsson H.M. Staudenmaier E. Bertolucci I. Mannelli G. Pierazzini P. Rehak A. Scribano F. Sergiampietri M.L. Vincelli 《Physics letters. [Part B]》1973,46(3):459-464
The ratio between the cross sections for the reactions and π?p → η→2γ n has been measured to be (2.4 ± 0.9) × 10?2, (2.1 ± 0.6) × 10?2 and (2.8 ± 1.3) × 10?2 at 3.8,6,8 and 12 GeV/c incident momentum respectively.At the same momenta the cross section for πt- p → neutrals is (1.48 ± 0.09) mb, (0.86 ± 0.05) mb, (0.64 ± 0.04) mb and (0.42±0.03) mb. 相似文献
17.
R. Brandelik W. Braunschweig H.-U. Martyn H.G. Sander D. Schmitz W. Sturm W. Wallraff D. Cords R. Felst R. Fries E. Gadermann H. Hultschig P. Joos W. Koch U. Kötz H. Krehbiel D. Kreinick S. Yamada 《Physics letters. [Part B]》1977,70(3):387-392
The semileptonic and leptonic decay modes of charmed hadrons produced in e+e? collisions above 4 GeV in the cm have been investigated by selecting events with a single electron plus at least two charged tracks. The electron momentum spectrum peaks near 0.5 GeV/c with few events above 0.7 GeV/c. The spectrum excludes large rates for the decays and , but is compatible with , or a mixture of both. The semileptonic branching ratio is obtained both by comparing the inclusive electron cross section with the total cross section attributable to charm, and by studying the fraction of events containing a second electron. The semileptonic charm branching ratios obtained are 0.11 ± 0.03 and 0.16 ± 0.06 respectively. A single event with three electrons and hadrons is found, consistent with the estimated background. The 90% confidence upper limit for σ(e+e? → 3e + hadrons) is 0.1 nb. 相似文献
18.
M.J. Corden J.D. Dowell J. Garvey R.J. Homer M. Jobes I.R. Kenyon T. McMahon R.C. Owen K.C.T.O. Sumorok R.J. Vallance P.M. Watkins J.A. Wilson P. Sonderegger B. Chaurand A. Romana R. Salmeron 《Physics letters. [Part B]》1981,98(3):220-224
J/ψ production at 40 GeV/c by π±, K±, p and incident on hydrogen has been studied and results compared with those obtained on tungsten in the same experiment. On hydrogen, J/ψ cross-section ratios relative to π? have been measured to be (for . The suppression of the proton induced cross sections shows the importance of calence quark-antiquark fusiin J/ψ production at this energy (i.e. MJ2/ψ/s=0.13). 相似文献
19.
Alkali atoms were scattered with hyperthermal energies from a clean and an oxygen covered (θ ≈ 0.5 ML) W(110) surface. The trapping probability of K and Na atoms on oxygen covered W(110) has been measured as a function of incoming energy (0–30 eV) and incident angle. A considerable enhancement of trapping on the oxygen covered surface compared to a clean surface was observed. At energies above 25 eV there are still K and Na atoms being trapped by the oxygen covered surface. From the temperature dependence of the mean residence time τ of the initially trapped atoms the pre-exponential factor τ0 and the desorption energy Q were derived using the relation: . On clean W(110) we obtained for Li: , Q = (2.78 ± 0.09) eV; for Na: τ0 = (9 ± 3) × 10?14 sec, Q = (2.55 ± 0.04) eV; and for K: τ0 = (4 ± 1) × 10?13 sec, Q = (2.05 ± 0.02) eV. Oxygen covered W(110) gave for Na: τ0 = (7 ±3) × 10?15 sec, Q = (2.88 ± 0.05) eV; and for K: , Q = (2.48 ±0.05) eV. The adsorption on clean W(110) has the features of a supermobile two-dimentional gas; on the oxygen covered W(110) adsorbed atoms have the partition function of a one-dimen-sional gas. The binding of the adatoms to the surface has a highly ionic character in the systems of the present experiment. An estimate is given for the screening length of the non-perfect conductor W(110):ks?1≈ 0.5 Å. 相似文献
20.
C. Bruneton J. Bystricky G. Cozzika J. Deregel A. Derevschikov Y. Ducros A. Gaidot Yu. Kazarinov M. Kazarinov V. Kanavets B. Khatchaturov F. Lehar A. De Lesquen Yu. Matulenko J.P. Merlo A. Mecshanin S. Miyazhita J. Movchet V. Solovyanov 《Physics letters. [Part B]》1973,44(5):471-473
We report our first measurements of the polarization in the elastic scattering of negative pions from polarized protons at an incident pion momentum of 40 GeV/c. The momentum-transfer region covered was 0.08 < |t| < 1.3 (GeV/c)2. The angular distribution of the polarization exhibits a first minimum of ~ ? 5% and the well-known zero around t ≈ ? 0.6 (GeV/c)2. The energy variation of the first minimum (at around t = ? 0.2) may be expressed in a simple form, . 相似文献