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T. R. Edgecock,
O. Caretta,
T. Davenne,
C. Densham,
M. Fitton,
D. Kelliher,
P. Loveridge,
S. Machida,
C. Prior,
C. Rogers, [......],
A. Bogacz,
J. S. Berg,
D. Stratakis,
H. Witte,
P. Snopok,
N. Bliss,
M. Cordwell,
A. Moss,
S. Pattalwar, M. Apollonio
[show abstract]
[hide abstract]
ABSTRACT: The EUROnu project has studied three possible options for future, high
intensity neutrino oscillation facilities in Europe. The first is a Super Beam,
in which the neutrinos come from the decay of pions created by bombarding
targets with a 4 MW proton beam from the CERN High Power Superconducting Proton
Linac. The far detector for this facility is the 500 kt MEMPHYS water
Cherenkov, located in the Fr\'ejus tunnel. The second facility is the Neutrino
Factory, in which the neutrinos come from the decay of {\mu}+ and {\mu}- beams
in a storage ring. The far detector in this case is a 100 kt Magnetised Iron
Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in
which the neutrinos come from the decay of beta emitting isotopes, in
particular 6He and 18Ne, also stored in a ring. The far detector is also the
MEMPHYS detector in the Fr\'ejus tunnel. EUROnu has undertaken conceptual
designs of these facilities and studied the performance of the detectors. Based
on this, it has determined the physics reach of each facility, in particular
for the measurement of CP violation in the lepton sector, and estimated the
cost of construction. These have demonstrated that the best facility to build
is the Neutrino Factory. However, if a powerful proton driver is constructed
for another purpose or if the MEMPHYS detector is built for astroparticle
physics, the Super Beam also becomes very attractive.
05/2013;
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R. Barate,
D. Buskulic,
D. Decamp,
P. Ghez,
C. Goy,
J.-P. Lees,
A. Lucotte,
E. Merle,
M.-N. Minard,
J.-Y. Nief, [......],
J.M. Nachtman,
J. Nielsen,
W. Orejudos,
Y.B. Pan,
Y. Saadi,
I.J. Scott,
J. Walsh,
Sau Lan Wu,
X. Wu,
G. Zobernig
[show abstract]
[hide abstract]
ABSTRACT: An improved measurement of the forward-backward asymmetry in decays is presented, based on a sample of 4.1 million hadronic Z decays collected by ALEPH between 1991 and 1995. Data are analysed as a function of polar angle of the event axis and b purity. The event tagging efficiency and mean b-jet hemisphere charge are measured directly from data. From the measured forward-backward jet charge asymmetry, the b quark asymmetry at is determined to be: AbFB=0.1017±0.0038(stat.)±0.0032(syst.). In the context of the Standard Model this corresponds to a value of the effective weak mixing angle of sin2θWeff=0.23109±0.00096.
Physics Letters B 03/2013; · 3.95 Impact Factor
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R. Barate,
D. Buskulic,
D. Decamp,
P. Ghez,
C. Goy,
J.-P. Lees,
A. Lucotte,
E. Merle,
M.-N. Minard,
J.-Y. Nief, [......],
J.M. Nachtman,
J. Nielsen,
W. Orejudos,
Y.B. Pan,
Y. Saadi,
I.J. Scott,
J. Walsh,
Sau Lan Wu,
X. Wu,
G. Zobernig
[show abstract]
[hide abstract]
ABSTRACT: Starting from a sample of four million hadronic Z decays collected with the ALEPH detector at LEP, 404 charged and neutral B mesons are fully reconstructed and used to look for resonant structure in the Bπ system. An excess of events is observed above the expected background in the Bπ mass spectrum at a mass ≈5.7 GeV/c2, consistent with the production and decay to B(∗)π of the B∗∗ states predicted by Heavy Quark Symmetry (HQS). In the framework of HQS, it is found that the mass of the state is MeV/c2 and the relative production rate of the B∗∗ system is . In the same sample of B mesons, significant Bπ± charge-flavour correlations are observed, which may prove important for tagging the initial B state in future CP violation studies.
Physics Letters B 03/2013; · 3.95 Impact Factor
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R. Barate,
D. Buskulic,
D. Decamp,
P. Ghez,
C. Goy,
S. Jezequel,
J.-P. Lees,
A. Lucotte,
M.-N. Minard,
J.-Y. Nief, [......],
J. Nielsen,
W. Orejudos,
Y.B. Pan,
Y. Saadi,
I.J. Scott,
J. Walsh,
Sau Lan Wu,
X. Wu,
J.M. Yamartino,
G. Zobernig
[show abstract]
[hide abstract]
ABSTRACT: The mass of the W boson is obtained from reconstructed invariant mass distributions in W-pair events. The sample of W pairs is selected from 10.65 pb−1 collected with the ALEPH detector at a mean centre-of-mass energy of 172.09 GeV. The invariant mass distribution of simulated events are fitted to the experimental distributions and the following W masses are obtained:The statistical errors are the expected errors for Monte Carlo samples of the same integrated luminosity as the data. The combination of these three measurements gives:
Physics Letters B 03/2013; · 3.95 Impact Factor
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D. Buskulic,
I. De Bonis,
D. Decamp,
P. Ghez,
C. Goy,
J.-P. Lees,
A. Lucotte,
M.-N. Minard,
P. Odier,
B. Pietrzyk, [......],
M. Schmitt,
I.J. Scott,
V. Sharma,
J.D. Turk,
A.M. Walsh,
Sau Lan Wu,
X. Wu,
J.M. Yamartino,
M. Zheng,
G. Zobernig
[show abstract]
[hide abstract]
ABSTRACT: Searches for supersymmetric particles produced in e+e− collisions at centre-of-mass energies of 130 and 136 GeV have been performed in a data sample of 5.7 pb−1 collected in the autumn of 1995 by the ALEPH detector at LEP. No candidate events were found, allowing limits to be set on the masses and production cross-sections of scalar leptons, scalar tops, charginos and neutralinos. The domains previously excluded at LEP1 are substantially extended. For instance, masses of gaugino-like charginos smaller than 67.8 GeV/c2 are excluded at the 95% C.L. for scalar neutrino masses larger than 200 GeV/c2.
Physics Letters B 03/2013; · 3.95 Impact Factor
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D. Buskulic,
I. De Bonis,
D. Decamp,
P. Ghez,
C. Goy,
J.-P. Lees,
A. Lucotte,
M.-N. Minard,
J.-Y. Nief,
P. Odier, [......],
W. Orejudos,
Y.B. Pan,
Y. Saadi,
I.J. Scott,
A.M. Walsh,
Sau Lan Wu,
X. Wu,
J.M. Yamartino,
M. Zheng,
G. Zobernig
[show abstract]
[hide abstract]
ABSTRACT: A search for pair production of new heavy leptons has been performed assuming different scenarios for the mixing of the new particles with Standard Model leptons. No candidate events were found in a data sample corresponding to an integrated luminosity of 5.6 pb−1 collected by the ALEPH detector at centre-of-mass energies of 130 and 136 GeV. New limits on production cross-sections and on masses of sequential leptons were obtained which significantly extend the mass regions excluded at LEP1. For instance, charged heavy leptons with masses below 63.5 GeV/c2 are excluded at 95% C.L. for mass differences to the associated neutral lepton of more than 7 GeV/c2.
Physics Letters B 03/2013; · 3.95 Impact Factor
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D. Buskulic,
I. De Bonis,
D. Decamp,
P. Ghez,
C. Goy,
J.-P. Lees,
A. Lucotte,
M.-N. Minard,
P. Odier,
B. Pietrzyk, [......],
Y. Saadi,
M. Schmitt,
I.J. Scott,
V. Sharma,
A.M. Walsh,
Sau Lan Wu,
X. Wu,
J.M. Yamartino,
M. Zheng,
G. Zobernig
[show abstract]
[hide abstract]
ABSTRACT: Searches for charginos and neutralinos produced in e+e− collisions at centre-of-mass energies of 130 and 136 GeV have been performed under the assumptions that R-parity is not conserved, that the dominant R-parity violating coupling involves only leptonic fields, and that the lifetime of the lightest supersymmetric particle can be neglected. In the 5.7 pb−1 data sample collected by ALEPH, no candidate events were found. As a result, chargino and neutralino masses and couplings are constrained and the domains previously excluded at LEP1 are extended.
Physics Letters B 03/2013; · 3.95 Impact Factor
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R Barate,
D Buskulic,
D Decamp,
P Ghez,
C Goy,
J.-P Lees,
A Lucotte,
M.-N Minard,
J.-Y Nief,
B Pietrzyk, [......],
J Nielsen,
W Orejudos,
Y.B Pan,
Y Saadi,
I.J Scott,
J Walsh,
Sau Lan Wu,
X Wu,
J.M Yamartino,
G Zobernig
[show abstract]
[hide abstract]
ABSTRACT: The data collected at centre-of-mass energies ranging from 130 to 172 GeV by ALEPH at LEP, corresponding to an integrated luminosity of 27.5 pb−1, are analysed in a search for pair-produced charged Higgs bosons H±. Three analyses are employed to select the , and final states. No evidence for a signal is found. Mass limits are set as a function of the branching fraction for H±→τν. Charged Higgs bosons with masses below 52 GeV/c2 are excluded at 95% C.L. independently of , thus significantly improving on existing limits.
Physics Letters B 03/2013; · 3.95 Impact Factor
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R Barate,
D Buskulic,
D Decamp,
P Ghez,
C Goy,
J.-P Lees,
A Lucotte,
M.-N Minard,
J.-Y Nief,
B Pietrzyk, [......],
J Nielsen,
W Orejudos,
Y.B Pan,
Y Saadi,
I.J Scott,
J Walsh,
Sau Lan Wu,
X Wu,
J.M Yamartino,
G Zobernig
[show abstract]
[hide abstract]
ABSTRACT: The e+e−→W+W− cross section is measured in a data sample collected by ALEPH at a mean centre-of-mass energy of 172.09 GeV, corresponding to an integrated luminosity of 10.65 pb−1. Cross sections are given for the three topologies, fully leptonic, semi-leptonic and hadronic of a W-pair decay. Under the assumption that no other decay modes are present, the W-pair cross section is measured to be The existence of the triple gauge boson vertex of the Standard Model is clearly preferred by the data. The decay branching ratio of the W boson into hadrons is measured to be , allowing a determination of the CKM matrix element |Vcs|=0.98±0.14(stat.)±0.03(syst.).
Physics Letters B. 03/2013;
-
R. Barate,
D. Buskulic,
D. Decamp,
P. Ghez,
C. Goy,
S. Jezequel,
J.-P. Lees,
A. Lucotte,
M.-N. Minard,
J.-Y. Nief, [......],
J. Nielsen,
W. Orejudos,
Y.B. Pan,
Y. Saadi,
I.J. Scott,
J. Walsh,
Sau Lan Wu,
X. Wu,
J.M. Yamartino,
G. Zobernig
[show abstract]
[hide abstract]
ABSTRACT: The triple gauge-boson couplings, αWΦ, αW and αBΦ, have been measured using 34 semileptonically and 54 hadronically decaying W+W− candidate events. The events were selected in the data recorded during 1996 with the ALEPH detector at 172 GeV, corresponding to an integrated luminosity of 10.65 pb−1. The triple gauge-boson couplings have been measured using optimal observables constructed from kinematic information of W+W− events. The results are in agreement with the Standard Model expectation.
Physics Letters B 03/2013; · 3.95 Impact Factor
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D Buskulic,
D Casper,
I De Bonis,
D Decamp,
P Ghez,
C Goy,
J.-P Lees,
A Lucotte,
M.-N Minard,
P Odier, [......],
M Schmitt,
I.J Scott,
V Sharma,
J.D Turk,
A.M Walsh,
Sau Lan Wu,
X Wu,
J.M Yamartino,
M Zheng,
G Zobernig
[show abstract]
[hide abstract]
ABSTRACT: The lifetime of the Bs0 meson is measured in approximately 3 million hadronic Z decays accumulated using the ALEPH detector at LEP from 1991 to 1994. Seven different Ds− decay modes were reconstructed and combined with an opposite sign lepton as evidence of semileptonic Bs0 decays. Two hundred and eight Ds−ℓ+ candidates satisfy selection criteria designed to ensure precise proper time reconstruction and yield a measured Bs0 lifetime of τ(Bs0) = 1.59−0.15+0.17 (stat) ±0.03 (syst) ps. Using a larger, less constrained sample of events, the product branching ratio is measured to be (stat) −0.14+0.13 (syst) %.
Physics Letters B 12/2012; · 3.95 Impact Factor
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D. Buskulic,
I. De Bonis,
D. Decamp,
P. Ghez,
C. Goy,
J.-P. Lees,
A. Lucotte,
M.-N. Minard,
P. Odier,
B. Pietrzyk, [......],
Y. Saadi,
M. Schmitt,
I.J. Scott,
V. Sharma,
A.M. Walsh,
Sau Lan Wu,
X. Wu,
J.M. Yamartino,
M. Zheng,
G. Zobernig
[show abstract]
[hide abstract]
ABSTRACT: The B0 - B̄0 average mixing parameter and b forward-backward asymmetry AFB0(b) are measured from a sample of about 4 200 000 Z → qq̄ events recorded with the ALEPH detector at LEP in the years 1990–1995. High transverse momentum electrons and muons produced in b semileptonic decays provide the tag of the quark flavour and of its charge.The average mixing parameter and the pole b asymmetry are measured to be = 0.1246 ± 0.0051stat ± 0.0052syst, AFB0(b) = 0.1008 ± 0.0043stat ± 0.0028syst. The value of sin2θweff = 0.23198 ± 0.00092 is extracted from the asymmetry measurement.
Physics Letters B 12/2012; · 3.95 Impact Factor
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Damir Buskulic,
I De Bonis,
D Décamp,
P Ghez,
C Goy,
J P Lees,
A Lucotte,
M N Minard,
J Y Nief,
P Odier, [......],
W Orejudos,
Y B Pan,
Y Saadi,
I J Scott,
A M Walsh,
Wu Sau Lan,
X Wu,
J M Yamartino,
M Zheng,
G Zobernig
[show abstract]
[hide abstract]
ABSTRACT: Using data obtained with the ALEPH detector at the Z resonance, a measure based on transverse momentum is shown to exhibit a correlation between the two halves of a hadronic event which cannot be explained by energy-momentum conservation, flavour conservation, the imposition of an event axis or imperfect event reconstruction. Two possible explanations based on Monte Carlo models are examined: a) ARIADNE, with the correlation forming early in the parton shower and with the transition from partons to hadrons playing only a minor part; b) JETSET, with the correlation forming at the fragmentation stage. A correlation technique based on a jet cluster analysis is used to make a comparison of the models with the data. It is concluded that both non-perturbative and perturbative effects make important contributions to the observed correlation.
Zeitschrift für Physik C 12/2012; 73(3):421.
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C. N. Booth,
P. Hodgson,
L. Howlett,
R. Nicholson,
E. Overton,
M. Robinson,
P. J. Smith, M. Apollonio,
G. Barber,
A. Dobbs,
J. Leaver,
K. R. Long,
B. Shepherd,
D. Adams,
E. Capocci,
E. McCarron,
J. Tarrant
[show abstract]
[hide abstract]
ABSTRACT: The pion-production target that serves the MICE Muon Beam consists of a
titanium cylinder that is dipped into the halo of the ISIS proton beam. The
design and construction of the MICE target system are described along with the
quality-assurance procedures, electromagnetic drive and control systems, the
readout electronics, and the data-acquisition system. The performance of the
target is presented together with the particle rates delivered to the MICE Muon
Beam. Finally, the beam loss in ISIS generated by the operation of the target
is evaluated as a function of the particle rate, and the operating parameters
of the target are derived.
11/2012;
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M G Catanesi,
M T Muciaccia,
E Radicioni,
S Simone,
R Edgecock,
M. Ellis,
S Robbins,
F J P Soler,
C Gössling,
M Mass, [......],
G Giannini,
G. Santin,
Y. Hayato,
A Ichikawa,
T Kobayashi,
J Burguet-Castell,
J J Gómez-Cadenas,
P Novella,
M. Sorel,
A Tornero
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9th International Symposium on Wild Boar and other Suids; 09/2012
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