-
E Rouleau,
B Jesson,
A Briaux,
C Nogues, V Chabaud,
L Demange,
J Sokolowska,
F Coulet,
E Barouk-Simonet,
Y J Bignon, [......],
J Fournier,
A Hardouin,
D Muller,
J P Peyrat,
C Toulas,
N Uhrhammer,
V Vidal,
D Stoppa-Lyonnet,
I Bieche,
R Lidereau
[show abstract]
[hide abstract]
ABSTRACT: Hereditary breast cancers account for up to 5-10 % of breast cancers and a majority are related to the BRCA1 and BRCA2 genes. However, many families with breast cancer predisposition do not carry any known mutations for BRCA1 and BRCA2 genes. We explored the incidence of rare large rearrangements in the coding, noncoding and flanking regions of BRCA1/2 and in eight other candidate genes--CHEK2, BARD1, ATM, RAD50, RAD51, BRIP1, RAP80 and PALB2. A dedicated zoom-in CGH-array was applied to screen for rearrangements in 472 unrelated French individuals from breast-ovarian cancer families that were being followed in eight French oncogenetic laboratories. No new rearrangement was found neither in the genomic regions of BRCA1/2 nor in candidate genes, except for the CHEK2 and BARD1 genes. Three heterozygous deletions were detected in the 5' and 3' flanking regions of BRCA1. One large deletion introducing a frameshift was identified in the CHEK2 gene in two families and one heterozygous deletion was detected within an intron of BARD1. The study demonstrates the usefulness of CGH-array in routine genetic analysis and, aside from the CHEK2 rearrangements, indicates there is a very low incidence of large rearrangements in BRCA1/2 and in the other eight candidate genes in families already explored for BRCA1/2 mutations. Finally, next-generation sequencing should bring new information about point mutations in intronic and flanking regions and also medium size rearrangements.
Breast Cancer Research and Treatment 04/2012; 133(3):1179-90. · 4.43 Impact Factor
-
P. Abreu,
W. Adam,
T. Adye,
P. Adzic,
I. Ajinenko,
Z. Albrecht,
T. Alderweireld,
G. D. Alekseev,
R. Alemany,
T. Allmendinger, [......],
O. Yushchenko,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
A. Zintchenko,
P. Zoller,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: The rapidity-rank structure of pp¯ pairs is used to analyze the
mechanism of baryon production in hadronic Z0 decay. The
relative occurrence of the rapidity-ordered configuration pMp¯,
where /M is a meson, and that of pp¯ adjacent pairs is compared.
The data are found to be consistent with predictions from a mechanism
producing adjacent-rank pp¯ pairs, without requiring
`string-ordered' pMp¯ configurations. An upper limit of 15% at 90%
confidence is determined for the pMp¯ contribution.
Physics Letters B 08/2000; 490:61-70. · 3.95 Impact Factor
-
P. Abreu,
W. Adam,
T. Adye,
P. Adzic,
I. Ajinenko,
Z. Albrecht,
T. Alderweireld,
G. D. Alekseev,
R. Alemany,
T. Allmendinger, [......],
O. Yushchenko,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
A. Zintchenko,
P. Zoller,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: A study of b semileptonic decays into D, Dπ+/- and
D*π+/- final states is presented. The
D0, D+ and D*+ mesons are exclusively
reconstructed in Z decay data recorded from 1992 to 1995 in the DELPHI
experiment at LEP. The overall branching fractions are measured to
be:BR(b-->D0l-ν¯lX)=(7.04+/-
0.34(stat)+/-0.36(syst.exp)+/-0.17(BRD))%,BR(b--
>D+l-ν¯lX)=(2.72+/-
0.19(stat)+/-0.16(syst.exp)+/-0.18(BRD))%,BR(b--
>D*+l-ν¯lX)=(2.75+/-
0.17(stat)+/-0.13(syst.exp)+/-0.09(BRD))%,where the
D0 and D+ results include also contributions from
D*0 and D*+ decays. A fit to the distribution of
the π+/- impact parameter to the primary interaction
vertex provides a measurement of the b semileptonic branching fractions
into the D0π+/-X,
D+π+/-X and D*+π+/-X
final states. Assuming that single pion decay modes of B mesons
dominate, the partial rates for
B¯-->Dπl-νl¯ and
B¯-->D*πl-νl¯ have been
obtained, corresponding to a total branching
fraction:BR(B¯-->Dπl-νl¯)+BR(B¯--
>D*πl-νl¯)=(3.40+/-0.52(stat)+/-
0.32(syst))%.This result agrees well with the observed difference
between the total B semileptonic branching fraction and the sum of the
B¯-->Dl-νl¯ and
D*l-νl¯ branching fractions.
Physics Letters B 02/2000; 475:407-428. · 3.95 Impact Factor
-
K Borer,
V.G. Palmieri,
S. Janos,
J Buytaert, V Chabaud,
P Chochula,
P. Collins Dijkstra,
C Parkes,
S. Saladino,
T. Ruf, [......],
O. Dormond,
R. Frei,
L. Casagrande,
T. Bowcock,
C. Da Via,
I. Konorov,
S Paul,
L Schmitt,
G Ruggiero,
I Stavitski
[show abstract]
[hide abstract]
ABSTRACT: This paper presents results on the measurement of the cluster shapes, resolution and charge collection e#ciency of a double sided silicon microstrip detector after irradiation with 24 GeV protons to a fluence of 3.5 10 14 p/cm 2 and operated at cryogenic temperatures. An empirical model is presented which describes the expected cluster shapes as a function of depletion depth, and is shown to agree with the data. It is observed that the clusters on the p-side broaden if the detector is under-depleted, leading to a degradation of resolution and e#ciency. The model is used to make predictions for detector types envisaged for the LHC experiments. The results also show that at cryogenic temperature the charge collection e#ciency varies depending on the operating conditions of the detector and can reach values of 100% at unexpectedly low bias voltage. By analysing the cluster shapes it is shown that these variations are due to changes in depletion depth. This phenomenon, kno...
08/1999;
-
DELPHI Collaboration,
P. Abreu,
W. Adam,
T. Adye,
P. Adzic,
Z. Albrecht,
T. Alderweireld,
G. D. Alekseev,
R. Alemany,
T. Allmendinger, [......],
J. Yi,
O. Yushchenko,
A. Zaitsev,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: The cross-section for the process
e+e--->W+W- has been
measured with the data sample collected by DELPHI at an average
centre-of-mass energy of 182.65 GeV and corresponding to an integrated
luminosity of 53 pb-1. Based on the 770 events selected as WW
candidates, the cross-section for the doubly resonant process
σ(e+e--->W+W-
)=15.86 +/-0.69 (stat) +/-0.26 (syst) pb has been measured and
found to be in good agreement with the Standard Model expectation. The
branching fractions of the W decay were also measured. From these a
value of the CKM mixing matrix element Vcs=0.985+/-0.073
(stat)+/-0.025 (syst) was derived. Our previously published WW
cross-section measurements and the derived measurement of mW
have been revised and updated with the present cross-section measurement
to yield mW=80.49+/-0.43(stat)+/-0.09(syst)+/-0.03(LEP)
GeV/c2.
Physics Letters B 05/1999; 456:310-321. · 3.95 Impact Factor
-
DELPHI Collaboration,
P. Abreu,
T. Adye,
P. Adzic,
I. Ajinenko,
G. D. Alekseev,
R. Alemany,
P. P. Allport,
S. Almehed,
U. Amaldi, [......],
G. Wolf,
J. Yi,
O. Yushchenko,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: The events with two photons and missing (transverse) energy collected by the DELPHI detector at centre-of-mass energies between
130 GeV and 183 GeV have been studied to search for processes of the type e+e- → YY with the subsequent decay Y → X7, where X is an undetectable neutral particle. Reactions of this kind are expected in
supersymmetric models, where the Y particle can be either the lightest neutralino, decaying to a photon and a gravitino, or
the next-to-lightest neutralino, decaying to a photon and the lightest neutralino. To study the case of long-lived Y particles,
a search for single-photon events with the reconstructed photon axis pointing far from the beam interaction region has also
been performed. No evidence for a deviation from Standard Model expectations has been observed in the data and upper limits
have been derived on the signal cross-section as a function of the the X and Y masses and of the Y mean decay path.
European Physical Journal C 04/1999; 6(3):371-384. · 3.63 Impact Factor
-
DELPHI Collaboration,
H. B. Crawley,
A. Firestone,
J. Grahl,
J. W. Lamsa,
D. W. Lane,
R. Mc Kay,
W. T. Meyer,
E. I. Rosenberg,
L. Gorn, [......],
U. Mueller,
K. Muenich,
O. Passon,
R. Reinhardt,
M. A. E. Schyns,
M. Siebel,
P. Sponholz,
B. Ueberschaer,
H. Wahlen,
D. Wicke
[show abstract]
[hide abstract]
ABSTRACT: Data taken by DELPHI during the 1995 and 1996 LEP runs have been used to search for the supersymmetric partners of electron,
muon and tau leptons and of top and bottom quarks. The observations are in agreement with standard model predictions. Limits
are set on sfermion masses. Searches for long lived scalar leptons from low scale supersymmetry breaking models exclude stau
masses below 55 GeV/c2 at the 95% confidence level, irrespective of the gravitino mass.
European Physical Journal C 04/1999; 6(3):385-401. · 3.63 Impact Factor
-
DELPHI Collaboration,
W. Adam,
T. Adye,
I. Ajinenko,
G. D. Alekseev,
R. Alemany,
P. P. Allport,
S. Almehed,
U. Amaldi,
S. Amato, [......],
O. Yushchenko,
F. Zach,
A. Zaitsev,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: Oscillations of B0s mesons were studied in events
with a large transverse momentum lepton selected from 3.2 million
hadronic Z0 decays registered by DELPHI between 1991 and
1994. A limit on the mass difference between the physical
B0s stateswas obtained by combining the results
obtained in three channels.
Physics Letters B 10/1997; 414:382-400. · 3.95 Impact Factor
-
P. Abreu,
W. Adam,
T. Adye,
G. D. Alekseev,
R. Alemany,
P. P. Allport,
S. Almehed,
U. Amaldi,
S. Amato,
P. Andersson, [......],
O. Yushchenko,
F. Zach,
A. Zaitsev,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: The spin density matrix elements for the ρ0,
K*0(892) and φ produced in hadronic Z0 decays
are measured in the DELPHI detector. There is no evidence for spin
alignment of the K*0(892) and φ in the region
xp <= 0.3 (xp = p/pbeam), where
ρ00 = 0.33 +/- 0.05 and ρ00 = 0.30 +/-
0.04, respectively. In the fragmentation region, xp >=
0.4, there is some indication for spin alignment of the
ρ0 and K*0(892), since ρ00 =
0.43 +/- 0.05 and ρ00 = 0.46 +/- 0.08, respectively.
These values are compared with those found in meson-induced hadronic
reactions. For the φ, ρ00 = 0.30 +/- 0.04 for
xp >= 0.4 and 0.55 +/- 0.10 for xp >= 0.7.
The off-diagonal spin density matrix element ρ1-1 is
consistent with zero in all cases.
Physics Letters B 01/1997; 406:271-286. · 3.95 Impact Factor
-
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
R. Alemany,
P. P. Allport,
S. Almehed, [......],
A. Zaitsev,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: A search for high mass photon pairs from the processese^ + e^ - to ell ^
+ ell ^ - γ γ ,e^ + e^ - to qbar qγ γ ande^ + e^
- to ν bar ν γ γ with the DELPHI detector at LEP I is
reported. From a data sample containing 3.5 million hadronic
Z0 decays, collected by DELPHI during the years 1991 to 1994,
79 events with two charged leptons and two isolated photons were
selected with photon pair masses above 10 GeV/c2, where
76±6 events were predicted from standard sources. In the same
data sample, noν bar ν γ γ candidates were found and
no accumulation of events was visible for γγ masses above 10
GeV/c2 in theqbar qγ γ channel. Upper limits at
95% confidence level on the Z0 branching ratios for the three
different channels were extracted from the data. In the mass region m
γγ >30 GeV/c2 the limits obtained
are between 3×10-6 and
4×10-6.
Zeitschrift für Physik C 05/1996; 72:179-190.
-
DELPHI Collaboration,
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
R. Alemany,
P. P. Allport, [......],
A. Zaitsev,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: A search for high mass photon pairs from the processes$e^ + e^ - \to \ell ^ + \ell ^ - \gamma \gamma $e^ + e^ - \to \ell ^ + \ell ^ - \gamma \gamma ,$e^ + e^ - \to q\bar q\gamma \gamma $e^ + e^ - \to q\bar q\gamma \gamma and$e^ + e^ - \to \nu \bar \nu \gamma \gamma $e^ + e^ - \to \nu \bar \nu \gamma \gamma with the DELPHI detector at LEP I is reported. From a data sample containing 3.5 million hadronic Z0 decays, collected by DELPHI during the years 1991 to 1994, 79 events with two charged leptons and two isolated photons were
selected with photon pair masses above 10 GeV/c2, where 76±6 events were predicted from standard sources. In the same data sample, no$\nu \bar \nu \gamma \gamma $\nu \bar \nu \gamma \gamma candidates were found and no accumulation of events was visible forγγ masses above 10 GeV/c2 in the$q\bar q\gamma \gamma $q\bar q\gamma \gamma channel. Upper limits at 95% confidence level on the Z0 branching ratios for the three different channels were extracted from the data. In the mass regionm
γγ
>30 GeV/c2 the limits obtained are between 3×10−6 and 4×10−6.
Zeitschrift für Physik C 04/1996; 72(2):179-190.
-
DELPHI Collaboration,
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
R. Alemany,
P. P. Allport, [......],
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
R. Zuberi,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: This paper presents an update of the measurement of the mean lifetime of theB
s
0 meson. CombiningD
s−ℓ,D
s−h,φ−ℓ and inclusiveD
s final states from the 3.2 million hadronic Z decays collected by DELPHI between 1991 and 1994, theB
s
0 mean lifetime was measured to be:τ(B
s
0)=1.67±0.14 ps.
Zeitschrift für Physik C 04/1996; 71(1):11-30.
-
DELPHI Collaboration,
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
R. Alemany,
P. P. Allport, [......],
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
R. Zuberi,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: A measurement of the mass difference,Δm
d
, between the two physical B
d
0 states has been obtained from the analysis of the impact parameter distribution of a lepton emitted at large transverse momentum
(p
t
) relative to the jet axis and from the analysis of the flight distance distribution of secondary vertices tagged by either
a highp
t
lepton or an identified kaon. In the opposite hemisphere of the event, the charge of the initial quark has been evaluated
using a highp
t
lepton, a charged kaon or the mean jet charge. With 1.7 million hadronic Z0 decays recorded by DELPHI between 1991 and 1993,Δm
d
is found to be:
Dmd = 0.531 - 0.046 + 0.050 (stat.) ±0.078 (syst.) ps - 1 .\Delta m_d = 0.531_{ - 0.046}^{ + 0.050} (stat.) \pm 0.078 (syst.) ps^{ - 1} .
.
Zeitschrift für Physik C 04/1996; 72(1):17-30.
-
DELPHI Collaboration,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
R. Alemany,
P. P. Allport,
S. Almehed, [......],
A. Zaitsev,
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: Rare decays of beauty particles were studied in several charmless modes using the data collected with the DELPHI detector
at LEP from 1991 to 1994. These decays are mediated by both tree levelb→u and one-loop penguinb→s, d transitions. Evidence for charmlessB decays was obtained in two body hadronic modes. The branching ratios ofB
d,s
0 toπ
+
π
− orK
+
π
− andB
u
− toρ
0
π
− orK*0
π
− were found to be (2.8−1.0+1.5±0.2)×10−5 and (1.7−0.8+1.2±0.2)×10−4 respectively. The fraction of these decays with a charged kaon in the final state that is not from the spectators quark, was measured to be 0.58±0.18. Upper limits were set at 90% confidence level on the branching ratios for three and
four body charmless hadronic decays in the range of (1–3)×10−4, for inclusive radiativeb→sγ decays at 5.4×10−4, for the exclusive radiative decaysB
d
0→K*(892)0
γ andB
s
0→φ(1020)γ at 2.1×10−4 and 7.0×10−4 respectively, and for dineutrino decaysb ® sn[`(n)]b \to s\nu \bar \nu , in the exclusive channelsBd0 ® K* (892)0 n[`(n)]B_d^0 \to K^* (892)^0 \nu \bar \nu andBs0 ® f(1020)n[`(n)]B_s^0 \to \phi (1020)\nu \bar \nu at 1.0×10−3 and 5.4×10−3 respectively. The limits on dineutrino decays constrain theories with a newU(1) gauge boson coupling predominantly to the third family of fermions.
Zeitschrift für Physik C 04/1996; 72(2):207-220.
-
DELPHI Collaboration,
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
R. Alemany,
P. P. Allport, [......],
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
R. Zuberi,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: The interference between initial and final state radiation in the processe
+
e
−→μ
+
μ
− at √s≈MZ has been studied by measuring the forward-backward asymmetry as a function of the acoplanarity angle between the final state
muons. The interference is expected to be sensitive to the space-time separation of the initial and final state radiation.
The measured asymmetry distribution has been compared to theoretical predictions using thekoralz generator, with and withoutO(a){\mathcal{O}}(\alpha ) interference. The magnitude of the interference between initial and final state radiation was found to be of the order predicted
and to follow the expected distribution. Using the theoretical predictions, a value of
GZ = 2.50 ±0.21 (stat.) ±0.06 (syst.) GeV.\Gamma _{\rm Z} = 2.50 \pm 0.21 (stat.) \pm 0.06 (syst.) GeV.
has been extracted. The interpretation of this result is discussed. There is an additional uncertainty in the estimate ofΓ
Z from as yet uncalculated higher order interference terms. By assuming a value ofΓ
Z consistent with the world average, the data were used to estimate the size of these uncalculated corrections.
Zeitschrift für Physik C 04/1996; 72(1):31-38.
-
DELPHI Collaboration,
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
R. Alemany,
P. P. Allport, [......],
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
R. Zuberi,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: The average lifetime ofb-baryons has been studied using 3×106 hadronicZ
0 decays collected by the DELPHI detector at LEP. Three methods have been used, based on the measurement of different observables:
the proper decay time distribution of 206 vertices reconstructed with aΛ, a lepton and an oppositely charged pion; the impact parameter distribution of 441 muons with high transverse momentum accompanied
by aΛ in the same jet; and the proper decay time distribution of 125Λ
c-lepton decay vertices with theΛ
c exclusively reconstructed through itspKπ,pK
0 andΛ3π decay modes. The combined result is:
t(b - baryon) = (1.254 - 0.109 + 0.121 (stat) ±0.04(syst) - 0.05 + 0.03 (syst)) ps \begin{gathered} \tau (b - baryon) = (1.254_{ - 0.109}^{ + 0.121} (stat) \hfill \\ \pm 0.04(syst)_{ - 0.05}^{ + 0.03} (syst)) ps \hfill \\ \end{gathered}
where the first systematic error is due to experimental uncertainties and the second to the uncertainties in the modelling
of theb-baryon production and semi-leptonic decay. Including the measurement recently published by DELPHI based on a sample of proton-muon
vertices, the averageb-baryon lifetime is:
t(b - baryon) = (1.255 - 0.102 + 0.115 (stat) ±0.05) ps\tau (b - baryon) = (1.255_{ - 0.102}^{ + 0.115} (stat) \pm 0.05) ps
.
Zeitschrift für Physik C 01/1996; 71(2):199-210.
-
DELPHI Collaboration,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
P. P. Allport,
S. Almehed,
S. J. Alvsvaag, [......],
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
R. Zuberi,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: An analysis is presented of inclusiveπ
0 production inZ
0 decays measured with the DELPHI detector. At low energies,π
0 decays are reconstructed by using pairs of converted photons and combinations of converted photons and photons reconstructed
in the barrel electromagnetic calorimeter (HPC). At high energies (up to
xp = 2 pp /Ös = 0.75x_p = 2 \cdot p_\pi /\sqrt s = 0.75
) the excellent granularity of the HPC is exploited to search for two-photon substructures in single showers. The inclusive
differential cross section is measured as a function of energy forqq andbb events. The number ofπ
0’s per hadronicZ
0 event isN(π
0)/Z
had
0
=9.2±0.2(stat)±1.0(syst) and forbb events the number ofπ
0’s is N(π
0)/bb=10.1±0.4(stat)±1.1(syst). The ratio of the number ofπ
0’s inbb events to hadronicZ
0 events is less affected by the systematic errors and is found to be 1.09±0.05±0.01. The measuredπ
0 cross sections are compared with the predictions of different parton shower models. For hadronic events, the peak position
in theξ
p=ln(1/xp) distribution isξ*
p
=3.90
−0.14
+0.24
. The average number ofπ
0’s from the decay of primary B hadrons is found to be N(B→π
0
X)/B hadron=2.78±0.15(stat)±0.60(syst).
Zeitschrift für Physik C 11/1995; 69(1):561-573.
-
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
P. P. Allport,
S. Almehed,
F. M. L. Almeida, [......],
Z. Zalewski,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
V. Zhigunov,
N. I. Zimin,
M. Zito,
D. Zontar,
R. Zuberi,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: An analysis of inclusive production of K0 and the meson resonances K*(892), 0(770),f
0(975) andf
2(1270) in hadronic decays of the Z0 is presented, based on about 973,000 multihadronic events collected by the DELPHI detector at LEP during 1991 and 1992. Overall multiplicities have been determined as 1.9620.060 K0 mesons, 0.7120.067 K*(892) and 1.210.150(770) per hadronic Z0 decay. The average multiplicities off
0(975) for scaled momentum,x
p
, in the range 0.05x
p
0.6 and off
2(1270) for 0.05x
p
1.0 are 0.0980.016 and 0.1700.043 respectively. Thef
0(975) and 0(770)x
p
-spectra have similar shapes. Thef
2(1270)/0(770) ratio increases withx
p
. The average multiplicities and the differential cross sections are compared with the JETSET Parton Shower model. The model with default parameters fails to reproduce the experimental K0 momentum spectrum at low momentum, describes the K*(892) and 0(770)x
p
-spectrum shapes, but significantly overestimates their production rates.
Zeitschrift für Physik C 11/1995; 65(4):587-602.
-
DELPHI Collaboration,
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
P. P. Allport,
S. Almehed, [......],
A. Zalewska,
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
N. I. Zimin,
M. Zito,
D. Zontar,
R. Zuberi,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: The hadronic photon structure functionF
2
γ
has been measured in theQ
2 range from 4 to 30 GeV2/c
4 and down tox values of order 0.001, using data taken with the DELPHI detector at LEP between 1991 and 1993. A comparison is made with
severalF
2
γ
parameterizations with special emphasis on their lowx behaviour. A result on theQ
2 evolution ofF
2
γ
is presented.
Zeitschrift für Physik C 11/1995; 69(1):223-233.
-
P. Abreu,
W. Adam,
T. Adye,
E. Agasi,
I. Ajinenko,
R. Aleksan,
G. D. Alekseev,
P. P. Allport,
S. Almehed,
S. J. Alvsvaag, [......],
P. Zalewski,
D. Zavrtanik,
E. Zevgolatakos,
V. Zhigunov,
N. I. Zimin,
M. Zito,
D. Zontar,
R. Zuberi,
G. C. Zucchelli,
G. Zumerle
[show abstract]
[hide abstract]
ABSTRACT: A study of the production of strange octet and decuplet baryons in hadronic decays of the Z recorded by the DELPHI detector at LEP is presented. This includes the first measurement of the
average multiplicity. The total and differential cross sections, the event topology and the baryon-antibaryon correlations are compared with current hadronization models.
Zeitschrift für Physik C 11/1995; 67(4):543-553.
