共查询到20条相似文献,搜索用时 31 毫秒
1.
T. A. Armstrong R. P. Barnes M. Benayoun W. Beusch I. J. Bloodworth J. N. Carney D. DiBari C. J. Dodenhoff C. Evangelista D. Evans B. Ghidini B. R. French M. Girone A. Jacholkowski J. B. Kinson A. Kirk K. Knudson V. Lenti V. Manzari F. Navach A. Palano E. Quercigh M. Sené R. Sené G. Vassiliadis O. Villalobos Baillie M. F. Votruba 《Zeitschrift fur Physik C Particles and Fields》1992,54(3):371-376
The reactionppp
f
(
+
–
)p
s
, where the
+
–
system is centrally produced, has been studied at 300 GeV/c. The
+
–
mass spectrum shows evidence for a
0
decay mode of the (958) andf
1 (1285). The branching ratio (f
1(1285)
+
+)/(f
1(1285)
0
) is found to be 5.0±0.7. No evidence is found for a
0(770) decay mode of theE/f
1 (1420) for which an upper limit BR (E/f
1(1420)
0
)<0.08 at=" 95%=" cl=" is=">0.08> 相似文献
2.
M. I. Vysotsky 《Physics of Atomic Nuclei》2006,69(4):679-685
We determine the domains of the values of unitarity-triangle angle α allowed by charmless strangeless $B_d (\bar B_d )$ decays. 相似文献
3.
P. Weidenauer K. D. Duch M. Heel H. Kalinowsky F. Kayser E. Klempt B. May J. Reifenröther O. Schreiber M. Ziegler D. Bailey S. Barlag J. M. Butler U. Gastaldi R. Landua C. Sabev W. Dahme F. Feld-Dahme U. Schaefer W. R. Wodrich J. C. Bizot B. Delcourt J. Jeanjean H. Nguyen E. G. Auld D. A. Axen K. L. Erdman B. Howard R. Howard B. L. White S. Ahmad M. Comyn G. M. Marshall G. Beer L. P. Robertson M. Botlo C. Laa H. Vonach C. Amsler M. Doser J. Riedlberger U. Straumann P. Truöl ASTERIX Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,47(3):353-365
We have measured the branching ratios for \(\bar pp\) annihilation at rest intoπ + π ? η andπ + π ? η′ in hydrogen gas in two data samples that have different fractions ofS-wave andP-wave initial states. The branching ratios are derived from a comparison with the topological branching ratio for \(\bar pp\) annihilations into four charged pions of (49±4)% and the branching ratio intoπ + π ? π + π ? π 0 of (18.7±1.6)%. We find a significant reduction of the branching ratios fromP-states for \(\bar pp \to \pi ^ + \pi ^ - \eta \) andπ + π ? η′ in comparison toS-state annihilation. $$\begin{gathered} BR(S - wave \to \pi ^ + \pi ^ - \eta ) = (13.7 \pm 1.46) \cdot 10^{ - 3} \hfill \\ BR(P - wave \to \pi ^ + \pi ^ - \eta ) = (3.35 \pm 0.84) \cdot 10^{ - 3} \hfill \\ BR(S - wave \to \pi ^ + \pi ^ - \eta ') = (3.46 \pm 0.67) \cdot 10^{ - 3} \hfill \\ BR(P - wave \to \pi ^ + \pi ^ - \eta ') = (0.61 \pm 0.33) \cdot 10^{ - 3} . \hfill \\ \end{gathered} $$ In a partial wave analysis of theπ + π ? η Dalitz plot we find the following contributions: Phase space, \(a_2^ + (1320)\pi ^ \mp \) ,ηρ0 andf 2(1270)η: $$\begin{gathered} BR(S - wave \to \pi ^ + \pi ^ - \eta PS) = (6.31 \pm 1.22) \cdot 10^{ - 3} \hfill \\ BR(P - wave \to \pi ^ + \pi ^ - \eta PS) = (0.47 \pm 0.26) \cdot 10^{ - 3} \hfill \\ BR(^1 S_0 \to a_2^ \pm (1320)\pi ^ \mp ) = (2.59 \pm 0.73) \cdot 10^{ - 3} \hfill \\ BR(^3 S_1 \to a_2^ \pm (1320)\pi ^ \mp ) = (1.31 \pm 0.48) \cdot 10^{ - 3} \hfill \\ BR(P - wave \to a_2^ \pm (1320)\pi ^ \mp ) = (1.31 \pm 0.69) \cdot 10^{ - 3} \hfill \\ BR(^3 S_1 \to \rho \eta ) = (3.29 \pm 0.90) \cdot 10^{ - 3} \hfill \\ BR(^1 P_1 \to \rho \eta ) = (0.94 \pm 0.53) \cdot 10^{ - 3} \hfill \\ BR(^1 S_0 \to f_2 (1270)\eta ) = (0.083 \pm 0.086) \cdot 10^{ - 3} \hfill \\ BR(P - wave \to f_2 (1270)\eta ) = (0.64 \pm 0.26) \cdot 10^{ - 3} . \hfill \\ \end{gathered} $$ We find a 2 σ effect for the reaction \(\bar pp \to a_0^ \pm (980)\pi ^ \mp \) , \(a_0^ \pm \to \eta \pi ^ \pm \) , with a branching ratio of (0.13±0.07)·10?3. For η' production we give a branching ratio of \(\bar pp \to \rho \eta '\) of (1.81±0.44)·10?3 from3 S 1. We estmate a contribution of about 0.3·10?3 for ρη' fromP-states. The ratio of ρη and ρη' rpoduction is used to test the validity of the quark line rule. In theπ + π ? π + π ? γ final state we do not observe the reaction \(\bar pp \to \pi ^ + \pi ^ - \omega \) , ω→π + π ? λ and derive an upper limit of 3·10?3 for decay modeω→π + π ? λ. 相似文献
4.
5.
H. Sugimura S. Ajimura H. C. Bhang L. Busso M. Endo D. Faso T. Fukuda S. Hasegawa S. Hayakawa R. Honda Y. Ichikawa K. Imai N. Ishibashi T. Kishimoto R. Kiuchi K. Matsuda K. Matsuoka K. Miwa Y. Mizoi O. Morra S. Nagamiya M. Nakagawa H. Noumi R. Ota P. K. Saha H. Sako C. Samanta S. Sato Y. Shimizu K. Shirotori T. Soyama A. Sakaguchi T. Takahashi T. N. Takahashi T. Tanaka K. Yoshida 《Few-Body Systems》2013,54(7-10):1235-1238
We are planning to perform an experiment at J-PARC and produce new neutron-rich Λ hypernuclei by using the (π ?, K +) reaction (J-PARC E10). As the first step, we are planning to produce ${^6_{\Lambda}{\rm H}}$ hypernuclei with a 6Li target. To conduct this experiment, we are developing new detectors, those are scintillating fiber tracker, and silicon strip detector, for high rate operation to aim at increasing beam intensity up to 107/spill. As a result of beam test in Jun 2012, we are going to use high-rate beam at least 107/spill. 相似文献
6.
R. García-Martín B. Moussallam 《The European Physical Journal C - Particles and Fields》2010,70(1-2):155-175
We reconsider Muskhelishvili–Omnès (MO) dispersive representations of photon–photon scattering to two pions, motivated by the very high statistics results recently released by the Belle collaboration for charged as well as neutral pion pairs and also by recent progress in the determination of the low-energy π π scattering amplitude. Applicability of this formalism is extended beyond 1 GeV by taking into account inelasticity due to $K\bar{K}$ . A modified MO representation is derived which has the advantage that all polynomial ambiguities are collected into the subtraction constants and have simple relations to pion polarizabilities. It is obtained by treating differently the exactly known QED Born term and the other components of the left-hand cut. These components are approximated by a sum over resonances. All resonances up to spin two and masses up to ?1.3 GeV are included. The tensor contributions to the left-hand cut are found to be numerically important. We perform fits to the data imposing chiral constraints, in particular, using a model independent sum-rule result on the p 6 chiral coupling c 34. Such theoretical constraints are necessary because the experimental errors are dominantly systematic. Results on further p 6 couplings and pion dipole and quadrupole polarizabilities are then derived from the fit. The relevance of the new data for distinguishing between two possible scenarios of isospin breaking in the f 0(980) region is discussed. 相似文献
7.
A. Breakstone R. Campanini H. B. Crawley G. M. Dallavalle M. M. Deninno K. Doroba D. Drijard F. Fabbri A. Firestone H. G. Fischer H. Frehse W. Geist G. Giacomelli R. Gokieli M. Gorbics P. Hanke M. Heiden W. Herr L. D. Isenhower E. E. Kluge J. W. Lamsa R. A. Leacock T. Lohse R. Mankel W. T. Meyer G. Mornacchi T. Nakada M. Panter A. Putzer K. Rauschnabel B. Rensch F. Rimondi M. Schmelling G. P. Siroli J. D. Skeens R. Sosnowski M. Szczekowski O. Ullaland D. Wegener R. Yeung 《Zeitschrift fur Physik C Particles and Fields》1990,48(4):569-575
Data are presented on Pomeron-Pomeron interactions which produce a centralπ + π ? system in proton-proton collisions at \(\sqrt s = 62 GeV\) at the CERN Intersecting Storage Rings. This process may favor the production of gluonic bound states. A partial-wave analysis of theπ + π ? system shows evidence for the production of the statesf 0(975),f 0(1400), andf 2(1270). The fitted mass for thef 2(1270) is about 50 MeV below the world average. In addition, the production mechanism for thef 2(1270) is uniquely different from that for the other final states in that there is a correlation between the outgoing protons. this is consistent with a picture of two-gluon exchange with thef 2(1270) produced by gluon fusion, and could indicate that thef 2(1270) has a glueball component. 相似文献
8.
M. Aguilar-Benitez M. C. Albajar A. Ferrando J. A. Rubio J. Salicio I. Sjögren S. Rodebäck S. O. Holmgren R. Armenteros C. Dionisi Ph. Gavillet M. J. Losty P. F. Loverre M. Mazzucato L. Dobrzynski D. Pennino 《Zeitschrift fur Physik C Particles and Fields》1980,6(2):109-123
The reactionsπ ?p→K 0 ∑ 0(1385) andπ ? p→K + ∑ ?(1385) are studied at an incident momentum of 3.95 GeV/c using data from a high statistics bubble chamber experiment corresponding to approximately 90 events/μb. The total and differential cross sections and the density matrix elements of the Σ(1385) are presented. The results are compared with those obtained for the related processesπ pp→K + ∑ +(1385) and \(K^ - p \to \pi ^ \mp \sum ^ \pm (1385)\) in this energy range. Evidence is presented for the existence of production mechanisms with exotic exchanges in thet channel. 相似文献
9.
A. Antonelli R. Baldini M. E. Biagini S. Calcaterra M. Schioppa D. Bisello G. Busetto A. Castro M. Nigro L. Pescara P. Sartori L. Stanco J. E. Augustin L. Ayach G. Cosme F. Couchot F. Fulda G. Grosdidier B. Jean-Marie V. Lepeltier G. Szklarz 《Zeitschrift fur Physik C Particles and Fields》1992,56(1):15-19
The cross sections fore + e ?→π + π ? π 0 ande + e ?→ωπ + π ? have been measured in the 1.35 ≦ \(\sqrt s \) ≦2.4 GeV range from 1900 nb?1 collected by DM2 at DCI. The second process proceeds via a resonant state at ≈- 1660 MeV/c2, ≈- 280 MeV/c2 wide. The first one is larger than a VDM extrapolation from the ω-? peaks and, although does not show any clear structure, is compatible with the presence of the above resonance. 相似文献
10.
《Nuclear Physics A》1997,614(4):433-460
In the framework of intranuclear cascade (INC) type calculations, we study the momentum spectrum in the reactions (K−, K+) at a beam momentum of 1.65 GeV/c. The INC model calculations are compared with the relativistic impulse approximation (RIA) calculations to perform a detailed study of the reaction mechanism. We find that the INC model can reproduce the experimental data on various targets. Especially, in the low-momentum region, the forward-angle cross sections of the (K−, K+) reaction from light to heavy targets are consistently explained with the two-step strangeness exchange and production processes with various intermediate mesons, and φ, a0 and f0 productions and their decay into K+K−. In the two-step processes, inclusion of meson and hyperon resonances is found to be essential. 相似文献
11.
A.Ya. Berdnikov Ya.A. Berdnikov A.N. Ivanov V.F. Kosmach M.D. Scadron N.I. Troitskaya 《The European Physical Journal A - Hadrons and Nuclei》2000,9(3):425-432
The cross-sections for the reactions of the strange production p + p ↦ p + Λ + K+ and p + p ↦ p + Σ0 + K+ near thresholds of the final states pΛK+ and pΣ0K+ are calculated in the effective Lagrangian approach. Our approach is based on the dominant contribution of the one-pion exchange and strong interaction of the colliding protons in the initial state. The theoretical values of the cross-sections agree reasonably well with the experimental data. The polarization properties of the Λ- and Σ0-hyperons are discussed. 相似文献
12.
Bastian Kubis Rebekka Schmidt 《The European Physical Journal C - Particles and Fields》2010,70(1-2):219-231
We calculate radiative corrections to the flavor-changing neutral current process K→π ? + ? ?, both for charged and neutral kaon decays. While the soft-photon approximation is shown to work well for the muon channels, we discuss the necessity of further phase space cuts with electrons in the final state. It is also shown how to transfer our results to other decays such as η→γ ? + ? ? or ω→π 0 ? + ? ?. 相似文献
13.
14.
A.Ya. Berdnikov Ya.A. Berdnikov A.N. Ivanov V.A. Ivanova V.F. Kosmach M.D. Scadron N.I. Troitskaya 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):341-347
Polarization properties of strange baryons produced in pp reactions, p + p↦p + Λ0 + K+ and p + p↦p + Σ0 + K+, near thresholds of the final states pΛ0K+ and pΣ0K+ are analysed relative to polarizations of colliding protons. The cross-sections for pp reactions are calculated within the
effective Lagrangian approach accounting for strong pp rescattering in the initial state of colliding protons with a dominant
contribution of the one-pion exchange and strong final-state interaction of daughter hadrons (Eur. Phys. J. A 9, 425 (2000)).
Received: 22 October 2001 / Accepted: 14 November 2001 相似文献
15.
D. Alde F. G. Binon M. Boutemeur C. Bricman S. V. Donskov M. Gouanère A. V. Inyakin V. A. Kachanov G. V. Khaustov E. A. Knapp A. V. Kulik G. L. Landsberg A. A. Lednev J. P. Peigneux S. A. Polovnikov M. Poulet Yu. D. Prokoshkin S. A. Sadovsky V. D. Samoylenko P. M. Shagin A. V. Shtannikov A. V. Singovsky J. P. Stroot V. P. Sugonyaev 《Zeitschrift fur Physik C Particles and Fields》1992,54(4):549-551
The production of
0 system in
–
p
charge-exchange interactions at
– momenta 38 GeV/c and 100 GeV/c has been studied. The 2 and
0
0 decay modes of
leading to 4 and 8 final states respectively have been detected. No statistically significant peak is observed in the
0 mass spectrum in the range of 1.2 GeV÷2.1 GeV. An upper limit of 6·10–3 has been established for thea
2
0
(1320)
0 branching ratio. 相似文献
16.
T. F. Hoang 《Zeitschrift fur Physik C Particles and Fields》1991,49(1):109-114
The rapidity distributions of inclusive +
p –,K
0, 0 andK
* (892) atP
1ab=16 GeV/c of CERN experiments, are analyzed using the covariant partition temperatureT
p model. In the fireball system, apart fromK
* (892),T
p
*
m, no indication of thermal equilibrium, the average momentum
ofK
0 and
0 being approximately equal and in the opposite direction, the entropy density is practically the same forK
0 and
0 but less than that of –. It is found that the principle of equipartition holds rather for the momenta of ,K, and in the fireball system. 相似文献
17.
H. Dijkstra R. Bailey E. Belau T. Böhringer M. Bosman V. Chabaud C. Damerell C. Daum G. de Rijk S. Gill A. Gillman R. Gilmore Z. Hajduk C. Hardwick W. Hoogland B. D. Hyams R. Klanner S. Kwan U. Kötz G. Lütjens G. Lutz J. Malos W. Männer E. Neugebauer H. Palka M. Pepé J. Richardson K. Rybicki H. J. Seebrunner U. Stierlin R. J. Tapper H. G. Tiecke M. Turala G. Waltermann S. Watts P. Weilhammer F. Wickens L. W. Wiggers A. Wylie T. Zeludziewicz ACCMOR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1986,32(3):353-358
The joint production of ? mesons andπ ±,π 0,p, \(\bar p\) ,K s 0 andK ± is investigated using a sample of 600,000 inclusive ? meson events obtained in hadron Be interactions with incidentπ ±,p, \(\bar p\) andK ± beams. Evidence is presented for the joint production of ? mesons and strange particles produced with non-strange incident beams. With incidentK ± beam the number of additional strange particles is suppressed. The results are found to be in agreement with the qualitative predictions of a parton fusion model. The comparison with the Lund model for lowp T processes is fair. 相似文献
18.
T. A. Armstrong I. J. Bloodworth J. N. Carney B. R. French B. Ghidini J. B. Kinson V. Lenti A. Palano I. C. Print G. Vassiliadis O. Villalobos Baillie M. F. Votruba G. Zito R. Zitoun WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1987,34(1):33-38
The reactions π+ p→π+(K + K ? π+ π? p andpp→p(K + K ? π+ π?)p where the (K + K ? π+ π?) system is centrally produced have been studied at 85 GeV/c. 48% of the final state proceeds through single or double vector meson resonant production i.e.,K *0(890) (37%), ? (4%),ρ 0 (7%). Evidence is found for associatedK *0 (890) \(\bar K\) *o (890) production (6.4±1.1%) with a cross section ten times higher than that found for associated ? ? production in the same experiment. 相似文献
19.
M. R. Atayan I. V. Ajinenko Yu. A. Belokopytov H. Böttcher F. Botterweck M. M. Chapkin P. V. Chliapnikov F. Crijns A. De Roeck E. A. De Wolf K. Dziunikowska A. M. F. Endler Z. G. Garutchava G. R. Gulkanyan P. van Hal T. Haupt J. K. Karamyan Z. A. Kirakosyan D. Kisielewska W. Kittel S. S. Megrabyan F. Meijers A. B. Michałowska I. V. Nikolaenko K. Olkiewicz V. M. Ronjin A. M. Rybin E. K. Shabalina L. Scholten O. G. Tchikilev A. G. Tomaradze L. A. Tikhonova V. A. Uvarov F. Verbeure R. Wischnewski S. A. Zotkin 《Zeitschrift fur Physik C Particles and Fields》1991,50(3):353-360
Using the ARGUS detector at thee
+
e
– storage ring DORIS II at DESY, we have measured the inclusive production ofD
0,D
+ andD
*(2010)+ mesons inB decays and in nonresonante
+
e
– annihilation around 10.6 GeV. The inclusive branching ratios forB decays toD
0,D
+ andD
*+ mesons are found to be (52.2±8.2±3.5)%, (27.2±6.3±3.5)% and (34.8±6.0±3.5)% respectively. Thus,D
0 andD
+ production account for about 70% of the charm produced inB decays, neglectingbu contributions to the total width. The production cross sections and momentum spectra for continuume
+
e
– annihilation are also presented.Supported by the German Bundesministerium für Forschung und Technologie, under contract number 054DO51P 相似文献
20.
P. V. Fedorets M. Büscher V. P. Chernyshev S. N. Dymov V. Yu. Grishina C. Hanhart M. Hartmann V. Hejny V. Kleber H. R. Koch L. A. Kondratyuk V. P. Koptev A. E. Kudryavtsev P. Kulessa S. I. Merzliakov S. M. Mikirtychiants M. E. Nekipelov H. Ohm R. Schleichert H. Ströher V. E. Tarasov K. -H. Watzlawik I. Zychor 《Physics of Atomic Nuclei》2006,69(2):306-313
The reaction pp → dπ
+
η has been measured at a beam energy of T
p
= 2.65 GeV (p
p
= 3.46 GeV/c) using the ANKE spectrometer at COSY-Julich. The missing-mass distribution of the detected dπ
+ pairs exhibits a peak around the η mass on top of a strong background of multipion pp → dπ
+(nπ) events. The differential cross section d
4
σ/dΩd
dΩ
π
+
dp
d
dp
π
+ for the reaction pp → dπ
+
η has been determined model independently for two regions of phase space. Employing a dynamical model for the a
0
+
production allows one then to deduce a total cross section of σ(pp → da
0
+
→ dπ
+
η) = 1.1 ± 0.3stat ± 0.7syst μb for the production of π
+
η via the scalar a
0
+
(980) resonance and σ(pp → dπ
+
η) = 3.5 ± 0.3stat ± 1.0syst μb for the nonresonant production. Using the same model as for the interpretation of recent results from ANKE for the reaction
, the ratio of the total cross sections is
, which is in agreement with branching ratios in the literature.
The text was submitted by the authors in English. 相似文献