-
D Allasia,
C Angelini,
P Bagnaia,
Giustina Baroni,
J H Bartley,
G H Bertrand-Coremans,
V Bisi,
A Breslin,
Eric Henry Stoneley Burhop,
F Carena, [......],
A Romero,
J Sacton,
R Santonico,
R Sever,
F Russell Stannard,
P Tolun,
D N Tovee,
P Vilain,
J H Wickens,
G Wilquet
[show abstract]
[hide abstract]
ABSTRACT: The decay of charmed particles produced by high-energy neutrinos has been studied by an experiment using simultaneously emulsion, bubble chamber and counter techniques. Eight charmed particle candidates, 5 positively charged and 3 neutral, have been found in the emulsion, where their production and decay have been directly observed. One of these events is identified as a Λc+ baryon of mass 2.26±0.02 GeV/c2 which undergoes the decay Λc+→pK−π+ after a proper time of (7.3±0.1) · 10−13 s.
A statistical analysis of the other observed decays leads to the mean-life values τ+=(2.5−1.1+2.2) · 10−13 s, τ0=(0.53−0.25+0.57) · 10−13 s, for the sample of charged particles enriched by a similar event found in a previous experiment, and for the sample of 3 neutral particles, respectively. The former value is only slightly affected by including in the sample the Λc+ event or excluding that of the previous experiment.
Nuclear Physics B 02/2013; 176(1):13. · 4.66 Impact Factor
-
G Barr,
D. Cundy,
F Formenti,
B Gorini,
B. Hallgren,
W. Iwanski,
P. Kapusta,
G. Laverriere,
M Lenti,
O. Vossnack, [......],
M Sozzi,
R. Tripiccione,
H Dibon,
G Fischer,
M Jeitler,
M Markytan,
G Neuhofer,
M Pernicka,
A Taurok,
L Widhalm
[show abstract]
[hide abstract]
ABSTRACT: The trigger used for the collection of the samples of K decays in the NA48 experiment at CERN uses a novel pipeline design in order to satisfy the demanding specifications of a high rate kaon beam. The trigger algorithms, architecture and performance are described.
12/2001;
-
Na Experiment Fischer,
C. Avanzini,
G.D. Barr,
P. Calafiura,
M Cirilli,
F Costantini,
D. Cundy,
H Dibon,
F Formenti,
B Gorini, [......], G M Pierazzini,
M. Porcu,
D Rizzi,
F Rossi,
M Sozzi,
A Taurok,
R. Tripiccione,
M Velasco,
O. Vossnack,
H Wahl
[show abstract]
[hide abstract]
ABSTRACT: The "neutral" trigger system for the selection of K#P2##P4# decays of the NA48 CP-violation experiment is described. The trigger system has been implemented in a 40 MHz "dead-time free" pipeline to allow large rate reduction and high-trigger e#ciency. The trigger decision is based on the information from 13 340 cells of the electro-magnetic calorimeter. Every 25 ns the energy, the centre of gravity, the kaon lifetime and the number of peaks in calorimeter projections are calculated in the trigger. The pipeline system is described and the performance of the trigger during the 1997 data-taking period is discussed. # 1998 Published by Elsevier Science B.V. All rights reserved. *Corresponding author. E-mail: gunther.fischer@cern.ch. # The NA48 Collaboration is: Cagliari, Cambridge, CERN, Dubna, Edinbourgh, Ferrara, Firenze, Mainz, Orsay, Perugia, Pisa, Saclay, Siegen, Torino, Vienna, Warsaw. # On leave from Institute of Nuclear Physics, Cracow, Poland. 1.
02/1999;
-
B. Gorini,
C. Avanzini,
G.D. Barr,
P. Calafiura,
M. Cirilli,
F. Costantini,
D. Cundy,
H. Dibon,
G. Fischer,
F. Formenti, [......],
M. Porcu,
D. Rizzi,
F. Rossi,
M. Sozzi,
A. Taurok,
R. Tripiccione,
M. Velasco,
O. Vossnack,
H. Wahl,
M. Ziolkowski
[show abstract]
[hide abstract]
ABSTRACT: A first level trigger system based on a 40 MHz digital pipeline
has been developed for the CERN NA48 experiment, aiming at measuring CP
violation in K<sup>0</sup>→2π decays. The outputs of the 13340
cells of the 10 m<sup>3</sup> liquid krypton calorimeter are summed into
64 X and 64 Y projection strips and continuously digitised with 40 MHz
FADCs. This information is used to reconstruct at each clock cycle and
for the two calorimeter projections, the number of clusters, the impact
time of each of them (with a precision of about 3 ns), their total
energy and the first and second moments of the energy distribution.
Based on the quantities listed above, a programmable look-up table
system subsequently computes online the longitudinal position of the
kaon decay vertex and performs an event selection. The system is
described
IEEE Transactions on Nuclear Science 09/1998; · 1.45 Impact Factor
-
L. Bertanza,
A. Bigi,
P. Calafiura,
M. Calvetti,
R. Carosi,
M.C. Carrozza,
R. Casali,
C. Cerri,
R. Fantechi,
I. Mannelli, [......],
A. Wagner,
E. Augé,
D. Fournier,
L. Iconomidou-Fayard,
O. Perdereau,
A.C. Schaffer,
L. Serin,
M. Holder,
A. Kreutz,
R. Werthenbach
[show abstract]
[hide abstract]
ABSTRACT: A precision measurement of the KSK_{S} mean lifetime has been performed by comparing, in the same experimental setup, the distributions of two-pion decays of neutral kaons produced by high energy proton-beryllium interactions in two targets at a relative distance variable between 112 and 160 m. The value obtained combining the results from p+p-\pi^+\pi^- and p0p0\pi^0\pi^0 decays is tS = (0.8971 ±0.0021)10-10\tau_{S} = (0.8971 \pm 0.0021)~10^{-10} s.
Zeitschrift für Physik C 02/1997; 73(4):629-632.
-
G. D. Barr,
P. Buchholz,
D. Cundy,
N. Doble,
L. Gatignon,
P. Grafström,
R. Hagelberg,
H. Wahl,
K. J. Peach,
T. Beier, [......],
R. Casali,
C. Cerri,
I. Mannelli,
V. M. Marzulli,
A. Nappi, G. M. Pierazzini,
M. Holder,
A. Kreutz,
M. Rost,
R. Werthenbach
[show abstract]
[hide abstract]
ABSTRACT: Data from the NA31 experiment at CERN have been used to measure the branching ratio of the double Dalitz decay of the long-lived neutral kaon. Eight events have been found with negligible background. The measured distribution of the angle between the planes of the two e+e–-pairs favours aCP=–1 state for the long-lived neutral kaon.
Zeitschrift für Physik C 08/1995; 65(3):361-365.
-
A. Kreutz,
M. Holder,
M. Rost,
R. Werthenbach,
K. J. Peach,
H. Blümer,
R. Heinz,
K. Kleinknecht,
P. Mayer,
B. Panzer, [......],
A. Bigi,
P. Calafiura,
M. Calvetti,
R. Carosi,
R. Casali,
C. Cerri,
I. Mannelli,
V. Marzulli,
A. Nappi, G. M. Pierazzini
[show abstract]
[hide abstract]
ABSTRACT: Improved branching ratios were measured for theK
LG(KL ® 3p0 )/G(KL ® p+ p- p0 ) = 1.611 ±0.037\Gamma ({\rm K}_L \to 3\pi ^0 )/\Gamma ({\rm K}_L \to \pi ^ + \pi ^ - \pi ^0 ) = 1.611 \pm 0.037
and
G(KL ® 3p0 )/G(KL ® pev) = 0.545 ±0.010.\Gamma ({\rm K}_L \to 3\pi ^0 )/\Gamma ({\rm K}_L \to \pi ev) = 0.545 \pm 0.010.
From the first number an upper limit for I=5/2 and I=7/2 transitions in neutral kaon decay is derived. Using older results for the Ke3/K3 fraction, the 30 branching ratio is found to be(K
L
30)/
tot
=(0.2110.003), about a factor three more precise than from previous experiments.
Zeitschrift für Physik C 02/1995; 65(1):67-74.
-
A Kreutz,
M Holder,
M Rost,
R Werthenbach,
K J Peach,
H. Blümer,
R Heinz,
K Kleinknecht,
P Mayer,
B Panzer, [......],
A Bigi,
P. Calafiura,
M Calvetti,
R Carosi,
R Casali,
C Cerri,
I Mannelli,
V. Marzulli,
A Nappi, G M Pierazzini
[show abstract]
[hide abstract]
ABSTRACT: Improved branching ratios were measured for the $K_L \to 3 \pi^0 $ decay in a neutral beam at the CERN SPS with the NA31 detector: $\Gamma (K_L \to 3 \pi^0) / \Gamma (K_L \to \pi^+ \pi^- \pi^0) = 1.611 \pm 0.037$ and $\Gamma (K_L \to 3 \pi^0) / \Gamma (K_L \to \pi e \nu ) = 0.545 \pm 0.010$. From the first number an upper limit for $\Delta I =5/2$ and $\Delta I = 7/2 $ transitions in neutral kaon decay is derived. Using older results for the Ke3/K$\mu $3 fraction, the 3$\pi^0$ branching ratio is found to be $\Gamma (K_L \to 3 \pi^0 )/ \Gamma_{tot} = (0.211 \pm 0.003)$, about a factor three more precise than from previous experiments.
09/1994;
-
D. Allasia,
C. Angelini,
A. Baldini,
S. Barlag,
L. Bertanza,
A. Bigi,
V. Bisi,
F. Bobisut,
T. Bolognese,
R. Bonarelli, [......],
A. Romero,
A. M. Rossi,
A. Sconza,
P. Serra-Lugaresi,
A. Tenner,
G. W. van Apeldoorn,
P. van Dam,
D. Vignaud,
C. Visser,
R. Wigmans
[show abstract]
[hide abstract]
ABSTRACT: The total νμ and νμ 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
aνN = 0.62 +/- 0.05 and aνN = 0.33 +/- 0.03
(in units of 10-38 cm2/GeV), where the quoted
error is mainly systematic. The ratio of the cross sections is
σνN/σνN = 0.53 +/- 0.03.
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.
Nuclear Physics B 06/1984; 239:301-310. · 4.66 Impact Factor
-
D. Allasia,
C. Angelini,
S. Barlag,
L. Bertanza,
A. Bigi,
V. Bisi,
F. Bobisut,
T. Bolognese,
R. Bonarelli,
E. Calimani, [......],
A. M. Rossi,
J. Saudraix,
A. Sconza,
P. Serra-Lugaresi,
A. Tenner,
G. W. van Apeldoorn,
P. van Dam,
D. Vignaud,
C. Visser,
R. Wigmans
[show abstract]
[hide abstract]
ABSTRACT: The reactions
[`(v)]D ® m+ np- (ps )\bar vD \to \mu ^ + n\pi ^ - (p_s )
and
[`(v)]D ® m+ pp(ns )\bar vD \to \mu ^ + p\pi (n_s )
have been studied at antineutrino energies varying from 5 to 200 GeV. The cross sections for these reactions were determined from 545 and 300 selected events for each channel respectively. The first reaction was used for the study of the decay properties of the resonance that dominates this channel. The experimental results have been compared with the theoretical predictions of Rein and Sehgal [9] and of Fogli and Nardulli [10]. Using the first model we obtained for the axial form factor parameterM
a
=1.010.05 GeV/c2. With this value the model is in agreement with the experimentald/dQ
2 distributions forQ
2>0.25 GeV2 and with the distributions of the invariant hadronic massW. The isospin structure of the one-pion production has been investigated and compared with the results of other experiments.
Zeitschrift für Physik C 05/1983; 20(2):95-100.
-
C. Angelini,
P. Bagnaia,
G. Baroni,
J.H. Bartley,
G. Bertrand-Coremans,
V. Bisi,
A. Breslin,
E.H.S. Burhop,
F. Carena,
R. Casali, [......],
A. Romero,
J. Sacton,
R. Santonico,
R. Sever,
F.R. Stannard,
P. Tolun,
D.N. Tovee,
P. Villain,
J.H. Wickens,
G. Wilquet
[show abstract]
[hide abstract]
ABSTRACT: Two new examples of production by neutrinos and subsequent decay of charged charmed hadrons are reported. Together with two similar events reported previously they show that the lifetime of charged charmed particles is in the neighbourhood of 5 × 10−13 s, as expected from current theoretical models. One of the new events is identified as a baryon λc+ of mass 2.295 ± 0.015 GeV/c2 which undergoes the decay process λc+ → pπ+K− with a proper decay time (7.3 ± 0.1) × 10−13 s.
Physics Letters B 01/1979; 84(1):0370-2693. · 3.95 Impact Factor
-
Physics Letters B - PHYS LETT B. 01/1975; 56(2):190-192.
-
D Allasia,
C Angelini,
P Bagnaia,
Giustina Baroni,
J H Bartley,
G H Bertrand-Coremans,
V Bisi,
A Breslin,
Eric Henry Stoneley Burhop,
F Carena, [......],
A Romero,
J Sacton,
R Santonico,
R Sever,
F Russell Stannard,
P Tolun,
D N Tovee,
P Vilain,
J H Wickens,
G Wilquet
-
G.D. Barr,
P. Clarke,
D. Coward,
D. Cundy,
N. Doble,
L. Gatignon,
V. Gibson,
P. Grafström,
R. Hagelberg,
G. Kesseler, [......],
C. Cerri,
I. Mannelli,
A. Nappi, G.M. Pierazzini,
H. Burkhardt,
M. Holder,
G. Quast,
M. Rost,
W. Weihs,
G. Zech
[show abstract]
[hide abstract]
ABSTRACT: We have searched for the sequence of decays KL0→π0H0 and H0→e+e− at the CERN Super Proton Synchrotron (SPS), and have allowed for a non-zero H0 lifetime. Three candidates have been seen, consistent with an expected background of 3.3. Limits on the branching ratio product in the range 10−8–10−7 are presented as a function of the mass and lifetime of the H0. These can be used to restrict the neutral Higgs of the minimal standard model.
Physics Letters B.
-
H. Burkhardt,
P. Clarke,
D. Coward,
D. Cundy,
N. Doble,
L. Gatignon,
V. Gibson,
R. Hagelberg,
G. Kesseler,
J. Van Der Lans, [......],
E. Massa,
A. Nappi, G.M. Pierazzini,
C. Becker,
D. Heyland,
M. Holder,
G. Quast,
M. Rost,
W. Weihs,
G. Zech
[show abstract]
[hide abstract]
ABSTRACT: The double ratio R of the relative decay rates of the short- and long-lived neutral kaons into two charged and two neutral pions was measured to be 0.980±0.004±0.005. The deviation of R from the CP violation in the transition of the CP-odd K2 into two pions with ϵ′/ϵ=(3.3 ± 1.1)×10−3.
Physics Letters B.
-
H. Burkhardt,
P. Clarke,
D. Cundy,
N. Doble,
L. Gatignon,
R. Hagelberg,
G. Kesseler,
J. Van Der Lans,
I. Mannelli,
T. Miczaika, [......],
E. Massa,
A. Nappi, G.M. Pierazzini,
C. Becker,
D. Heyland,
M. Holder,
G. Quast,
M. Rost,
W. Weihs,
G. Zech
[show abstract]
[hide abstract]
ABSTRACT: The decay rates of KL → 2γ and KS → 2γ have been measured at the CERN SPS. The results are Γ(KL→2γ)/χ(KL→2π0)=0.632±0.004±0.008 and Γ(KS→2γ)/Γ(KL→2γ)=2.3 ±1.0±0.4. This is the first observation of KS→2γ decays.
Physics Letters B.
-
M.G. Setzu,
A. Nappi,
A. Beisser,
T. Beier,
H. Blümer,
P. Buchholz,
D. Coward,
K. Kleinknecht,
F. Leber,
B. Renk, [......],
M. Calvetti,
R. Carosi,
R. Casali,
R. Fantechi,
I. Mannelli,
V.M. Marzulli, G.M. Pierazzini,
M. Holder,
A. Kreutz,
R. Werthenbach
[show abstract]
[hide abstract]
ABSTRACT: The full data set of the NA31 experiment at CERN has been used to analyse the decay mode K0L→e+e−γγ. A signal of 47 events has been observed with an estimated background of 6.9 events. The total number of kaon decays in the decay volume was determined to be (2.1±0.1stat)·109. This corresponds to a branching ratio of .
Physics Letters B. 420:205-210.
-
D. Allasia,
C. Angelini,
A. Argento,
M. Baldo-Ceolin,
S. Barlag,
L. Bertanza,
F. Bianchi,
A. Bigi,
V. Bisi,
F. Bobisut, [......],
L. Riccati,
A. Romero,
A.M. Rossi,
A. Sconza,
P. Serra-Lugaresi,
A. Tenner,
A. Vianello,
D. Vignaud,
C. Visser,
R. Wigmans
[show abstract]
[hide abstract]
ABSTRACT: Data from an exposure of the BEBC bubbe chamber filled with deuterium to a wideband antineutrino beam have been used to obtain the x- and y-distributions for antineutrino scattering on the neutron and proton. The y-distribution have been fitted in order to determine the fraction of momentum carried by quarks and antiquarks of given flavour and their x- dependence.
Physics Letters B. 117:262-266.
-
V. Fanti,
A. Lai,
D Marras,
L. Musa,
A Nappi,
R Batley,
A Bevan,
R S Dosanjh,
R. Galik,
T. Gershon, [......],
S Wronka,
H Dibon,
G Fischer,
M Jeitler,
M Markytan,
I Mikulec,
G Neuhofer,
M Pernicka,
A Taurok,
L Widhalm
[show abstract]
[hide abstract]
ABSTRACT: The beam and detector, used for the NA48 experiment, devoted to the measurement of Re(ε′/ε), and for the NA48/1 experiment on rare KS and neutral hyperon decays, are described.
-
T Åkesson,
Michael G Albrow,
S Almehed,
J Richard Batley,
O Benary,
H Bøggild,
O Botner,
H Brody,
V D Burkert,
R Carosi, [......],
R H Schindler,
B L Schistad,
I Stumer,
M Sullivan,
J Thompson,
E N Vella,
W J Willis,
M Winik,
W Witzeling,
C Woody
