-
K M Crowe,
F H Heinsius,
P Kammel,
M Lakata,
T Degener,
H Koch,
M Kunze,
U Kurilla,
H Matthay,
K Peters, [......],
B. S. Zou,
C Volcker,
I Uman,
S Wallis-Plachner,
D Walther,
U Wiedner,
A. Berdoz,
R McCrady,
C A Meyer,
M. Suert
[show abstract]
[hide abstract]
ABSTRACT: We report on a measurement of the branching ratio of the rare decay #### relative to the well known decay ### 0 #. The #'s are produced in pp### and pp## 0 #. Eigenstate mixing and interference e#ects of the # and # 0 are taken into account, as well as coherent interference with the background. We find evidence for the non-resonant annihilation channel BR(pp####) = (3.5 1.3)10 -5 and limit the value of BR(####) to the range of (0.7 to 5.5)10 -4 depending on the degree of coherence with the background. 13.20.Jf Decays of other mesons Typeset using REVT E X 3 I. INTRODUCTION Radiative meson decays have been used to test various models of non-perturbative QCD, such as the quark model and vector dominance. The family of radiative vector meson to pseudoscalar meson (or vice versa) decays includes 11 di#erent decays. Of these, the decay #### (1.1) is the focus of this experiment. The decay # 0 ### is also poorly known, but because of the larger # 0 width, is more di#cu...
10/1999;
-
A. Abele,
S. Bischoff,
P. Blüm,
N. Djaoshvili,
D. Engelhardt,
A. Herbstrith,
C. Holtzhaußen,
M. Tischhäuser,
J. Adomeit,
B. Kämmle, [......],
P. Kammel,
M. Lakata,
M. Doser,
J. Kisiel,
R. Landua,
L. Montanet,
R. Ouared,
R. P. Haddock,
P. Hidas,
M. Suffert
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement and partial wave analysis of the final state
KLK+/-π-/+ of p¯p annihilation
at rest in liquid hydrogen. This reaction is important for the study of
the K¯K decay mode of scalar resonances, in particular, the
isovectors a0(980) and a0(1450). The determination
of the a0(1450) production also fixes the K¯K coupling
of the isoscalar f0(1500) which is discussed as a glueball.
We find
B(p¯p-->a0(1450)πa0(1450)-->K¯K)=(8.88+/-1.68)×10-4
and hence
B(p¯p-->f0(1500)πf0(1500)-->K¯K)=(4.52+/-0.36)×10-4.
The mass and width of a0(1450) are m=1480+/-30
MeV/c2 and Γ=265+/-15 MeV/c2, respectively.
For a0(980) we determine the relative ratio
B(p¯p-->a0πa0-->K¯K)/B(p¯p-->a0πa0-->πη)
=0.23+/-0.05 and its relative coupling, K¯K to πη, is
1.03+/-0.14.
Physical review D: Particles and fields 03/1998; 57:3860-3872.
-
A Abele,
S Bischoff,
P Blum,
N. Djaoshvili,
D Engelhardt,
M Tischhauser,
J Adomeit,
B Kammle,
J Meier,
P Schmidt, [......],
H Stock,
C Regenfus,
W Roethel,
C Volcker,
S Wallis,
D Walther,
C Zupancic,
P Kammel,
M Lakata,
M Doser
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement and partial wave analysis of the final state KLK Sigma ß Upsilon of ¯ pp annihilation at rest in liquid hydrogen. This reaction is important for the study of the ¯ KK decay mode of scalar resonances, in particular the isovectors a 0 (980) and a 0 (1450). The determination of the a 0 (1450) production also fixes the ¯ KK coupling of the isoscalar f 0 (1500) which is discussed as a glueball. We find B(¯pp ! a 0 (1450)ß; a 0 (1450)! ¯ KK) = (8:88 Sigma 1:68) Delta 10 Gamma4 and hence B(¯pp ! f 0 (1500)ß; f 0 (1500)! ¯ KK) = (4:52Sigma0:36) Delta 10 Gamma4 . The mass and width of a 0 (1450) are m = 1480Sigma30 MeV/c 2 and Gamma = 265 Sigma 15 MeV/c 2 , respectively. For a 0 (980) we determine the relative ratio B(¯pp! a 0 ß; a 0 ! ¯ KK)/ B(¯pp! a 0 ß; a 0 ! ßj) = 0:23 Sigma 0:05 and its relative coupling, ¯ KK to ßj, is 1:03 Sigma 0:14. 13.25.-k, 14.40.Cs, 14.40.Ev Typeset using REVT E X I. INTRODUCTION Proton-antiproton annihilation...
12/1997;
-
A. Abele,
J. Adomeit,
D. S. Armstrong,
C. A. Baker,
C. J. Batty,
M. Benayoun,
A. Berdoz,
K. Beuchert,
S. Bischoff,
P. Blüm, [......],
I. Scott,
R. Seibert,
C. Straßburger,
U. Strohbusch,
M. Suffert,
U. Thoma,
M. Tischhäuser,
C. Völcker,
D. Walther,
B. Zou
Nuclear Physics A 01/1997; 625:899-900. · 1.54 Impact Factor
-
A. Abele,
J. Adomeit,
C. Amsler,
D. S. Armstrong,
C. A. Baker,
B. M. Barnett,
C. J. Batty,
M. Benayoun,
A. Berdoz,
K. Beuchert, [......],
U. Thoma,
M. Tischhäuser,
D. Urner,
C. Völcker,
F. Walter,
D. Walther,
U. Wiedner,
J. Zoll,
B. S. Zou,
Č. ZupančiČ
[show abstract]
[hide abstract]
ABSTRACT: Crystal Barrel data on pp -> 5π0 at rest are presented.
Mass spectra for 2π0 combinations, 3π0 and
4π0 and decay angular distributions all differ
significantly from phase space. We present several ways of fitting the
data. All agree on the definite presence of the f0(1500),
observed in its 4π0 decay mode. It can decay into
ππ(1300) and into σσ where σ stands for the full
ππ S-wave amplitude.
Physics Letters B 01/1996; 380:453-460. · 3.95 Impact Factor
-
CRYSTAL BARREL Collaboration,
J. Adomeit,
C. Amsler,
D. S. Armstrong,
C. A. Baker,
B. M. Barnett,
C. J. Batty,
M. Benayoun,
A. Berdoz,
K. Beuchert, [......],
M. Suffert,
U. Thoma,
M. Tischhäuser,
D. Urner,
C. Völcker,
F. Walter,
D. Walther,
U. Wiedner,
B. S. Zou,
Č. Zupančič
[show abstract]
[hide abstract]
ABSTRACT: Data on
[`(p)]p ® hp0 p0 p0\bar pp \to \eta \pi ^0 \pi ^0 \pi ^0
taken at beam momenta of 1.2 and 1.94 GeV/c reveal evidence for twoI=0J
PC=2−+ resonances inηππ. The first, at 1645±14(stat.)±15(syst.) MeV with width 180
−21
+40
±25 MeV, decays toα
2(1320)π withL=0. It may be interpreted as the
q[`(q)]1q\bar q^1
D
2 partner ofπ
2(1670). A strong signal is also observed just above threshold inf
2(1270)η withL=0. It is 11–22 times stronger than is expected for the high mass tail of the 1645 MeV resonance. It can be fitted as a second
2−+ resonance at 1875±20±35 MeV with width 200±25±45 MeV. A third resonance havingJ
PC=2++ is observed at 2135±20±45 MeV withΛ=250±25±45 MeV, decaying to botha
2(1320)π andf
2(1270)η withL=1. There is no evidence for resonances with decays toa
0(980)π, ση orf
0(980)η.
Zeitschrift für Physik C 01/1996; 71(2):227-238.
-
C. Amsler,
D. S. Armstrong,
I. Augustin,
C. A. Baker,
B. M. Barnett,
C. J. Batty,
M. Benayoun,
K. Beuchert,
P. Birien,
P. Blüm, [......],
M. Tischhäuser,
D. Urner,
C. Völcker,
F. Walter,
D. Walther,
U. Wiedner,
N. Winter,
J. Zoll,
B. S. Zou,
Č. ZupančiČ
[show abstract]
[hide abstract]
ABSTRACT: We report the observation of nucleon resonances in the reaction pd ->
π0π0n for antiprotons stopping in liquid
deuterium. The process pd -> Δ(1232)π0 is
identified and its branching ratio determined to be (2.21 +/-
0.24).10-5.
Physics Letters B 01/1995; 352:187-192. · 3.95 Impact Factor
-
C. Amsler,
D. S. Armstrong,
I. Augustin,
C. A. Baker,
B. M. Barnett,
C. J. Batty,
K. Beuchert,
P. Birien,
P. Blüm,
R. Bossingham, [......],
U. Thoma,
D. Urner,
C. Völcker,
F. Walter,
D. Walther,
U. Wiedner,
N. Winter,
J. Zoll,
B. S. Zou,
Č Zupančič
[show abstract]
[hide abstract]
ABSTRACT: We report the first observations of Pontecorvo reactions of the type pd Xn. We fully reconstruct the outgoing meson and, for antiprotons stopped in liquid deuterium, we measure: BR(pd0)=(7.030.72)10–6, BR(pdn)=(3.19+0.48)10–6, BR(pdn)=(22.8+4.1)10–6, BR(pdn)1410–6 (at 95% confidence level). Assuming charge independence, our result for pd0n is compatible with measurements of the only other observed Pontecorvo reaction pd –p. The experimental ratios between the above branching ratios are in fair agreement with both the statistical model and dynamical two-step models (assumingN N annihilation into two mesons, with subsequent absorption of one meson on the remaining nucleon). This agreement suggests that there may be appreciable rates for Pontecorvo reactions producing final state mesons with masses above 1 GeV.
Zeitschrift für Physik A Hadrons and Nuclei 01/1995; 351(3):325-331.
-
C Amsler,
D. S. Armstrong,
I Augustin,
C A Baker,
B M Barnett,
C J Batty,
K Beuchert,
P Birien,
R Bossingham,
K Braune, [......],
K M Crowe,
T Degener,
H P Dietz,
M Doser,
D Engelhardt,
M Englert,
M A Faessler,
C Felix,
R Hackmann, M Herz
[show abstract]
[hide abstract]
ABSTRACT: We report the first observations of Pontecorvo reactions of the type pd ® Xn. We fully reconstruct the outgoing meson and, for antiprotons stopped in liquid deuterium, we measure: BR(pd ® p 0 n ) = (7.03 ± 0.72) x 10 -6 , BR(pd ® hn) = (3.19 ± 0.48) x 10 -6 , BR(pd ® wn ) = (22.8 ± 4.1) x 10 -6 , BR(pd ® h'n ) 14 x 10 -6 (at 95% confidence level). Assuming charge independence, our result for pd ® p 0 n is compatible with measurements of the only other observed Pontecorvo reaction pd ® p - p. The experimental ratios between the above branching ratios are in fair agreement with both the statistical model and dynamical two-step models (assuming NN annihilation into two mesons, with subsequent absorption of one meson on the remaining nucleon). This agreement suggests that there may be appreciable rates for Pontecorvo reactions producing final state mesons with masses above 1 GeV. 1) University of California, LBL, Berkeley, CA 94720, USA 2) Universität Bochum, D-44780 Bochum,...
09/1994;
-
A. Abele,
J. Adomeit,
C. Amsler,
D.S. Armstrong,
C.A. Baker,
B.M. Barnett,
C.J. Batty,
M. Benayoun,
A. Berdoz,
K. Beuchert, [......],
U. Strohbusch,
M. Suffert,
U. Thoma,
M. Tischhäuser,
D. Urner,
C. Völcker,
F. Walter,
D. Walther,
U. Wiedner,
B.S. Zou
[show abstract]
[hide abstract]
ABSTRACT: A study of p̄-annihilation in liquid deuterium into π−π0π0 and a spectator-proton is presented. A cut on the proton-momentum of ≤ 100 MeV/c ensures that annihilation takes place on a quasi-free neutron. A partial wave analysis shows contributions from three vector mesons, with masses and widths of (763.7 ± 3.2; 152.8 ± 4.3), (1411 ± 14; 343 ± 20); (1780−29+37; 275 ± 45) MeV/c2, respectively.
Physics Letters B.
-
T Case,
K M Crowe,
F H Heinsius,
P Kammel,
M Lakata,
T Degener,
H Koch,
M Kunze,
U Kurilla,
H Matthay, [......],
W Roethel,
C Volcker,
I Uman,
S Wallis-Plachner,
D Walther,
U Wiedner,
A. Berdoz,
R McCrady,
C A Meyer,
M Suffert
-
Crystal Barrel Collaboration,
A Abele,
B Adomeit,
C Amsler,
C A Baker,
B M Barnett,
C J Batty,
Maurice Benayoun,
S Bischoff,
P Blum, [......],
J S Suh,
U Thoma,
M Tischhauser,
I Uman,
C Volcker,
S Wallis-Plachner,
D Walther,
U Wiedner,
K Wittmack,
B. S. Zou
-
Crystal Barrel Collaboration,
C Amsler,
DS Armstrong,
C A Baker,
BM Barnett,
C J Batty,
K Beuchert,
P Birien,
P Blum,
R Bossingham, [......],
U Thoma,
M Tischhaeuser,
D Urner,
C Voelcker,
F Walter,
D Walther,
U Wiedner,
J Zoll,
BS Zou,
C Zupancic
-
Crystal Barrel Collaboration,
A Abele,
J Adomeit,
C Amsler,
C A Baker,
B M Barnett,
C J Batty,
Maurice Benayoun,
A. Berdoz,
S Bischoff, [......],
J S Suh,
U Thoma,
M Tischhauser,
I Uman,
C Volcker,
S Wallis-Plachner,
D Walther,
U Wiedner,
K Wittmack,
B. S. Zou
-
Crystal Barrel Collaboration,
A Abele,
J Adomeit,
C Amsler,
C A Baker,
B M Barnett,
C J Batty,
Maurice Benayoun,
A. Berdoz,
K Beuchert, [......],
C Strassburger,
U Strohbusch,
M Suffert,
U Thoma,
M Tischhauser,
C Volcker,
S Wallis,
D Walther,
U Wiedner,
B. S. Zou
-
Crystal Barrel Collaboration,
A Abele,
J Adomeit,
C Amsler,
C A Baker,
B M Barnett,
C J Batty,
Maurice Benayoun,
A. Berdoz,
K Beuchert, [......],
U Strohbusch,
M Suffert,
U Thoma,
M Tischhauser,
C Volcker,
S Wallis,
D Walther,
U Wiedner,
B. S. Zou,
C Zupancic
-
Crystal Barrel Collaboration,
A Abele,
J Adomeit,
C Amsler,
C A Baker,
B M Barnett,
C J Batty,
Maurice Benayoun,
A. Berdoz,
K Beuchert, [......],
U Strohbusch,
M Suffert,
U Thoma,
M Tischhauser,
C Volcker,
S Wallis,
D Walther,
U Wiedner,
B. S. Zou,
C Zupancic
-
Crystal Barrel Collaboration,
A Abele,
J Adomeit,
C Amsler,
C A Baker,
B M Barnett,
C J Batty,
Maurice Benayoun,
A. Berdoz,
K Beuchert, [......],
U Strohbusch,
M Suffert,
U Thoma,
M Tischhaeuser,
C Volcker,
S Wallis,
D Walther,
U Wiedner,
K Wittmack,
B. S. Zou
-
Crystal Barrel Collaboration,
A Abele,
J Adomeit,
C Amsler,
C A Baker,
B M Barnett,
C J Batty,
Maurice Benayoun,
A. Berdoz,
K Beuchert, [......],
H Stock,
C Strassburger,
U Strohbusch,
M Suffert,
U Thoma,
M Tischhauser,
C Volcker,
D Walther,
U Wiedner,
B. S. Zou
-
Crystal Barrel Collaboration,
A Abele,
J Adomeit,
C Amsler,
C A Baker,
B M Barnett,
C J Batty,
Maurice Benayoun,
A. Berdoz,
S Bischoff, [......],
U Thoma,
M Tischhauser,
I Uman,
C Volcker,
S Wallis-Plachner,
D Walther,
U Wiedner,
K Wittmack,
B. S. Zou,
C Zupancic
