-
PANDA Collaboration,
W. Erni,
I. Keshelashvili,
B. Krusche,
M. Steinacher,
Y. Heng,
Z. Liu,
H. Liu,
X. Shen,
Q. Wang, [......],
S. Wronka,
A. Wysocka,
B. Zwieglinski,
P. Bühler,
O. Hartman,
P. Kienle,
J. Marton,
K. Suzuki,
E. Widmann,
J. Zmeskal
[show abstract]
[hide abstract]
ABSTRACT: This document describes the technical layout and the expected performance of
the Straw Tube Tracker (STT), the main tracking detector of the PANDA target
spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner
tracking and is followed in beam direction by a set of GEM-stations. The tasks
of the STT are the measurement of the particle momentum from the reconstructed
trajectory and the measurement of the specific energy-loss for a particle
identification. Dedicated simulations with full analysis studies of certain
proton-antiproton reactions, identified as being benchmark tests for the whole
PANDA scientific program, have been performed to test the STT layout and
performance. The results are presented, and the time lines to construct the STT
are described.
European Physical Journal A 02/2013; 49(25):1-104. · 2.19 Impact Factor
-
PANDA Collaboration,
W. Erni,
I. Keshelashvili,
B. Krusche,
M. Steinacher,
Y. Heng,
Z. Liu,
H. Liu,
X. Shen,
Q. Wang, [......],
M. Plominski,
J. Szewinski,
K. Traczyk,
B. Zwieglinski,
P. Bühler,
A. Gruber,
P. Kienle,
J. Marton,
E. Widmann,
J. Zmeskal
[show abstract]
[hide abstract]
ABSTRACT: This document illustrates the technical layout and the expected performance
of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect
charged particles as close as possible to the interaction zone. Design criteria
and the optimisation process as well as the technical solutions chosen are
discussed and the results of this process are subjected to extensive Monte
Carlo physics studies. The route towards realisation of the detector is
outlined.
07/2012;
-
M. Agnello,
L. Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani,
S. Bufalino,
L. Busso, [......],
T. Nagae,
H. Outa,
A. Pantaleo,
V. Paticchio,
S. Piano,
R. Rui,
G. Simonetti, R. Wheadon,
A. Zenoni,
A. Gal
[show abstract]
[hide abstract]
ABSTRACT: Three candidate events of the neutron-rich hypernucleus 6{\Lambda}H were
uniquely identified in the FINUDA experiment at DA{\Phi}NE, Frascati, by
observing {\pi}+ mesons from the (K-stop,{\pi}+) production reaction on 6Li
targets, in coincidence with {\pi}-mesons from 6{\Lambda}H \rightarrow
6He+{\pi}- weak decay. Details of the experiment and the analysis of its data
are reported, leading to an estimate of (2.9\pm2.0)\cdot10-6/K- stop for the
6{\Lambda}H production rate times the two-body {\pi}- weak decay branching
ratio. The 6{\Lambda}H binding energy with respect to 5H + {\Lambda} was
determined jointly from production and decay to be B{\Lambda} = (4.0 \pm 1.1)
MeV, assuming that 5H is unbound with respect to 3H + 2n by 1.7 MeV. The
binding energy determined from production is higher, in each one of the three
events, than that determined from decay, with a difference of (0.98 \pm 0.74)
MeV here assigned to the 0+g.s. \rightarrow 1+ excitation. The consequences of
this assignment to {\Lambda} hypernuclear dynamics are briefly discussed.
03/2012;
-
M Agnello,
L Benussi,
M Bertani,
H C Bhang,
G Bonomi,
E Botta,
M Bregant,
T Bressani,
S Bufalino,
L Busso, [......],
T Nagae,
H Outa,
A Pantaleo,
V Paticchio,
S Piano,
R Rui,
G Simonetti, R Wheadon,
A Zenoni,
A Gal
[show abstract]
[hide abstract]
ABSTRACT: Evidence for the neutron-rich hypernucleus (Λ)(6)H is presented from the FINUDA experiment at DAΦNE, Frascati, studying (π+,π-) pairs in coincidence from the K(stop)(-) + (6)Li →(Λ)(6)H + π+ production reaction followed by (Λ)(6)H → (6)He + π- weak decay. The production rate of (Λ)(6) undergoing this two-body π- decay is determined to be (2.9 ± 2.0) × 10(-6)/K(stop)(-). Its binding energy, evaluated jointly from production and decay, is BΛ((Λ)(6)H) = (4.0 ± 1.1) MeV with respect to (5)H+Λ. A systematic difference of (0.98 ± 0.74) MeV between BΛ values derived separately from decay and from production is tentatively assigned to the (Λ)(6)H 0(g.s.)(+) → 1+ excitation.
Physical Review Letters 01/2012; 108(4):042501. · 7.37 Impact Factor
-
M. Agnello,
L. Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani,
S. Bufalino,
L. Busso, [......],
T. Nagae,
H. Outa,
A. Pantaleo,
V. Paticchio,
S. Piano,
R. Rui,
G. Simonetti, R. Wheadon,
A. Zenoni,
A. Gal
[show abstract]
[hide abstract]
ABSTRACT: Evidence for the neutron-rich hypernucleus 6{\Lambda}H is presented from the
FINUDA experiment at DA{\Phi}NE, Frascati, studying ({\pi}+, {\pi}-) pairs in
coincidence from the K- +6Li \rightarrow 6 H+{\pi}+ production reaction
followed by 6{\Lambda}H \rightarrow 6He + {\pi}- weak decay. The production
rate of 6{\Lambda}H undergoing this two-body {\pi}- decay is determined to be
(2.9\pm2.0)\cdot10-6/K-. Its binding energy, evaluated jointly from production
and decay, is B{\Lambda}(6{\Lambda}H) = (4.0\pm1.1) MeV with respect to
5H+{\Lambda}. A systematic difference of (0.98 \pm 0.74) MeV between B{\Lambda}
values derived separately from decay and from production is tentatively
assigned to the 6{\Lambda}H 0+g.s. \rightarrow 1+ excitation.
12/2011;
-
[show abstract]
[hide abstract]
ABSTRACT: The Micro Vertex Detector (MVD) for the PANDA experiment is designed and optimized to reconstruct the D mesons secondary vertices and to provide the maximum acceptance close to the interaction point. The experimental physics goals and setup require sophisticated solutions for the detector integration in order to minimise the material budget. The thermal power produced by the "on board" read-out electronics is fast removed using carbon foam as heat sink. Two types of carbon foam are under evaluation. The mechanical and thermal property behaviors after neutron irradiation test with neutrons have been studied. Results from finite element thermal analyses and test bench are also presented.
Journal of Instrumentation 12/2011; 6(12):C12015. · 1.87 Impact Factor
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FINUDA Collaboration,
M. Agnello,
L Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani,
S. Bufalino, [......],
O. Morra,
T Nagae,
H. Outa,
A. Pantaleo,
V. Paticchio,
S. Piano,
R. Rui,
G. Simonetti, R. Wheadon,
A Zenoni
[show abstract]
[hide abstract]
ABSTRACT: This letter is concerned with the study of the $K^-_{stop}A\rightarrow
\pi^\pm\Sigma^\mp A'$ reaction in p-shell nuclei, i.e., $^{6,7}Li$, $^9Be$,
$^{13}C$ and $^{16}O$. The $\pi^\pm\Sigma^\mp / K^-_{stop}$ emission rates are
reported as a function of $A$. These rates are discussed in comparison with
previous findings. The ratio $\pi^-\Sigma^+/\pi^+\Sigma^-$ in p-shell nuclei is
found to depart largely from that on hydrogen, which provides support for large
in-medium effects possibly generated by the sub-threshold $\Lambda(1405)$. The
continuum momentum spectra of prompt pions and free sigmas are also discussed
as well as the $\pi^\pm\Sigma^\mp$ missing mass behavior and the link with the
reaction mechanism. The apparatus used for the investigation is the FINUDA
spectrometer operating at the DA$\Phi$NE $\phi$-factory (LNF-INFN, Italy).
09/2011;
-
M Agnello,
L Benussi,
M Bertani,
H C Bhang,
G Bonomi,
E Botta,
M Bregant,
T Bressani,
S Bufalino,
L Busso, [......],
O Morra,
T Nagae,
H Outa,
A Pantaleo,
V Paticchio,
S Piano,
R Rui,
G Simonetti, R Wheadon,
A Zenoni
[show abstract]
[hide abstract]
ABSTRACT: The latest results from the FINUDA experiment on the Non-Mesonic Weak Decay (NMWD) channels of p-shell Λ-hypernuclei are presented and discussed. Spectra of protons from NMWD were obtained for 5ΛHe, 7ΛLi, 9ΛBe, 11ΛB, 12ΛC, 13ΛC, 15ΛN and 16ΛO. An estimation of the contributions of both Final State Interactions (FSI) and two-nucleon induced (2N) decay processes was performed, following a model independent approach. The previously published results are confirmed by a new analysis of the triple coincidence (π−, p, n) events.
Journal of Physics Conference Series 09/2011; 312(2):022010.
-
Finuda Collaboration,
M. Agnello,
L. Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani,
S. Bufalino, [......],
T. Nagae,
H. Outa,
A. Pantaleo,
V. Paticchio,
S. Piano,
R. Rui,
G. Simonetti, R. Wheadon,
A. Zenoni,
G. Garbarino
[show abstract]
[hide abstract]
ABSTRACT: The decay of Λ-hypernuclei without π emission, known as
Non-Mesonic Weak Decay (NMWD), gives an effective tool to investigate
ΔS=1 four-baryon interactions. It was theoretically suggested that
the two-nucleon induced mechanism could play a substantial role in
reproducing the observed NMWD decay rates and nucleon spectra, but at
present no direct evidence of such a mechanism has been obtained. The
FINUDA experiment, exploiting the possibility to detect both charged and
neutral particles coming from the hypernucleus decay, has allowed us to
deduce the relative weight of the two nucleon induced decay rate to the
total NMWD rate. The value of
Γ2N/Γ=0.21±0.07stat-0.02+0.03
has been deduced, well consistent with the previous determinations.
Physics Letters B 06/2011; 701:556-561. · 3.95 Impact Factor
-
M. Agnello,
L Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani,
S. Bufalino,
L Busso, [......],
T Nagae,
H. Outa,
A. Pantaleo,
V. Paticchio,
S. Piano,
R. Rui,
G. Simonetti, R. Wheadon,
A Zenoni,
G. Garbarino
[show abstract]
[hide abstract]
ABSTRACT: The decay of $\Lambda$-hypernuclei without pion emission, known as Non
Mesonic Weak Decay (NMWD), gives an effective tool to investigate $\Delta$S=1
four-baryon interactions. It was theoretically suggested that the two-nucleon
induced mechanism could play a substantial role in reproducing the observed
NMWD decay rates and nucleon spectra, but at present no direct evidence of such
a mechanism has been obtained. The FINUDA experiment, exploiting the
possibility to detect both charged and neutral particles coming from the
hypernucleus decay, has allowed us to deduce the relative weight of the two
nucleon induced decay rate to the total NMWD rate. The value of
$\Gamma_{2N}$/$\Gamma_{NMWD}$=0.24$\pm$${0.03_{stat}}^{+0.03_{sys}}_{{-{0.02_{sys}}}}$
has been deduced, with an error reduced by a factor more than two compared with
the previous assessment.
01/2011;
-
M. Agnello,
L. Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani,
S. Bufalino,
L. Busso, [......],
O. Morra,
T. Nagae,
H. Outa,
A. Pantaleo,
V. Paticchio,
S. Paino,
R. Rui,
G. Simonetti, R. Wheadon,
A. Zenoni
[show abstract]
[hide abstract]
ABSTRACT: A direct experimental evidence of the occurrence of the weak reaction
$\Lambda np\rightarrow nnp$ in nuclei has been obtained by the FINUDA
experiment. Three events have been found that can be attributed to
$^{7}_{\Lambda}$Li and $^{9}_{\Lambda}$Be two nucleon-induced non mesonic weak
decays. The kinematic analysis of such events is presented here.
01/2011;
-
FINUDA Collaboration,
M. Agnello,
L Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani,
S. Bufalino, [......],
O. Morra,
T Nagae,
H. Outa,
A. Pantaleo,
V. Paticchio,
S. Piano,
R. Rui,
G. Simonetti, R. Wheadon,
A Zenoni
[show abstract]
[hide abstract]
ABSTRACT: The FINUDA experiment collected data to study the production of hypernuclei
on different nuclear targets. The hypernucleus formation occurred through the
strangeness-exchange reaction $K^-_{stop} + \; ^AZ \rightarrow \; ^A_{\Lambda}Z
+ \pi^-$. From the analysis of the momentum of the emerging $\pi^-$, binding
energies and formation probabilities of $^7_{\Lambda}$Li, $^9_{\Lambda}$Be,
$^{13}_{\Lambda}$C and $^{16}_{\Lambda}$O have been measured and are here
presented. The behavior of the formation probability as a function of the
atomic mass number A is also discussed.
11/2010;
-
FINUDA Collaboration,
M. Agnello,
L Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani,
S. Bufalino, [......],
O. Morra,
T Nagae,
H. Outa,
A. Pantaleo,
V. Paticchio,
S. Piano,
R. Rui,
G. Simonetti, R. Wheadon,
A Zenoni
[show abstract]
[hide abstract]
ABSTRACT: The Non-Mesonic (NM) decay of $^4_\Lambda{\mathrm{He}}$ and
$^5_\Lambda{\mathrm{He}}$ in two-body channels has been studied by the FINUDA
Collaboration. Two-body NM decays of hypernuclei are rare and the existing
observations and theoretical calculations are scarce. The
$^4_\Lambda{\mathrm{He}}\rightarrow d+d,\; p+t$ decay channels simultaneously
observed by FINUDA on several nuclei are compared: the $pt$ channel is the
dominant one. The decay yields for the two decay channels are assessed for the
first time: they are $(1.37\pm 0.37)\times 10^{-5}/K^-_{stop}$ and $(8.3\pm
1.0)\times 10^{-5}/K^-_{stop}$, respectively. Due to the capability of FINUDA
of identifying $^5_\Lambda{\mathrm{He}}$ hypernuclei, a few
$^5_\Lambda{\mathrm{He}}\rightarrow d+t$ decay events have also been observed.
The branching ratio for this decay channel has been measured for the first
time: $(3.0\pm 2.3)\times 10^{-3}$.
10/2010;
-
M. Agnello,
A. Andronenkov,
G Beer,
L Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant,
T. Bressani, [......],
V. Paticchio,
S. Piano,
F. Pompili,
R. Rui,
M Sekimoto,
G. Simonetti,
A Toyoda, R. Wheadon,
A Zenoni,
G. Garbarino
[show abstract]
[hide abstract]
ABSTRACT: New spectra from the FINUDA experiment of the Non Mesonic Weak Decay (NMWD) proton kinetic energy for 9(Lambda)Be, 11(Lambda)B, 12(Lambda)C, 13(Lambda)C, 15 (Lambda)N and 16(Lambda)O are presented and discussed along with the published data on 5(Lambda)He and 7(Lambda)Li. Exploiting the large mass number range and the low energy threshold (15 MeV) for the proton detection of FINUDA, an evaluation of both Final State Interactions (FSI) and the two nucleon induced NMWD contributions to the decay process has been done. Based on this evaluation, a linear dependence of FSI on the hypernuclear mass number A is found and for the two nucleon stimulated decay rate the experimental value of Gamma2/Gammap=0.43+-0.25 is determined for the first time. A value for the two nucleon stimulated decay rate to the total decay rate Gamma2/GammaNMWD=0.24+-0.10 is also extracted. Comment: 11 pages and 2 figures
10/2009;
-
The PANDA Collaboration,
W. Erni,
I. Keshelashvili,
B. Krusche,
M. Steinacher,
Y. Heng,
Z Liu,
H Liu,
X Shen,
O. Wang, [......],
M. Plominski,
J. Szewinski,
K. Traczyk,
B. Zwieglinski,
P. Buehler,
A Gruber,
P. Kienle,
J. Marton,
E. Widmann,
J. Zmeskal
[show abstract]
[hide abstract]
ABSTRACT: This document is the Technical Design Report covering the two large spectrometer magnets of the PANDA detector set-up. It shows the conceptual design of the magnets and their anticipated performance. It precedes the tender and procurement of the magnets and, hence, is subject to possible modifications arising during this process. Comment: 10 pages, 14MB, accepted by FAIR STI in May 2009, editors: Inti Lehmann (chair), Andrea Bersani, Yuri Lobanov, Jost Luehning, Jerzy Smyrski, Technical Coordiantor: Lars Schmitt, Bernd Lewandowski (deputy), Spokespersons: Ulrich Wiedner, Paola Gianotti (deputy)
PANDA Collaboration. 07/2009;
-
The PANDA Collaboration: W. Erni,
I. Keshelashvili,
B. Krusche,
M. Steinacher,
Y. Heng,
Z. Liu,
H. Liu,
X. Shen,
O. Wang,
H. Xu, [......],
M. Plominski,
J. Szewinski,
K. Traczyk,
B. Zwieglinski,
P. Buehler,
A. Gruber,
P. Kienle,
J. Marton,
E. Widmann,
J. Zmeskal
[show abstract]
[hide abstract]
ABSTRACT: This document is the Technical Design Report covering the two large
spectrometer magnets of the PANDA detector set-up. It shows the
conceptual design of the magnets and their anticipated performance. It
precedes the tender and procurement of the magnets and, hence, is
subject to possible modifications arising during this process.
06/2009;
-
The FINUDA Collaboration,
M. Agnello,
A. Andronenkov,
G Beer,
L Benussi,
M. Bertani,
H. C. Bhang,
G. Bonomi,
E. Botta,
M. Bregant, [......],
S. Piano,
F. Pompili,
R. Rui,
A. Sanchez Lorente,
M Sekimoto,
G. Simonetti,
A Toyoda, R. Wheadon,
A Zenoni,
A Gal
[show abstract]
[hide abstract]
ABSTRACT: The FINUDA experiment performed a systematic study of the charged mesonic weak decay channel of $p$-shell $\Lambda$-hypernuclei. Negatively charged pion spectra from mesonic decay were measured with magnetic analysis for the first time for ${^{7}_{\Lambda}Li}$, ${^{9}_{\Lambda}Be}$, ${^{11}_{\Lambda}B}$ and ${^{15}_{\Lambda}N}$. The shape of the $\pi^{-}$ spectra was interpreted through a comparison with pion distorted wave calculations that take into account the structure of both hypernucleus and daughter nucleus. Branching ratios $\Gamma_{\pi^{-}}/\Gamma_{tot}$ were derived from the measured spectra and converted to $\pi^{-}$ decay rates $\Gamma_{\pi^{-}}$ by means of known or extrapolated total decay widths $\Gamma_{tot}$ of $p$-shell $\Lambda$-hypernuclei. Based on these measurements, the spin-parity assignment $1/2^+$ for ${^{7}_{\Lambda}Li}$ and $5/2^+$ for ${^{11}_{\Lambda}B}$ ground-state are confirmed and a spin-parity $3/2^+$ for ${^{15}_{\Lambda}N}$ ground-state is assigned for the first time. Comment: 14 pages, 5 figures
05/2009;
-
PANDA Collaboration,
W. Erni,
I. Keshelashvili,
B. Krusche,
M. Steinacher,
Y. Heng,
Z Liu,
H Liu,
X Shen,
O. Wang, [......],
P. Buehler,
A Gruber,
P. Kienle,
J. Marton,
E. Widmann,
J. Zmeskal,
M. F. M. Lutz,
B. Pire,
O. Scholten,
R. Timmermans
[show abstract]
[hide abstract]
ABSTRACT: To study fundamental questions of hadron and nuclear physics in interactions of antiprotons with nucleons and nuclei, the universal PANDA detector will be built. Gluonic excitations, the physics of strange and charm quarks and nucleon structure studies will be performed with unprecedented accuracy thereby allowing high-precision tests of the strong interaction. The proposed PANDA detector is a state-of-the art internal target detector at the HESR at FAIR allowing the detection and identification of neutral and charged particles generated within the relevant angular and energy range. This report presents a summary of the physics accessible at PANDA and what performance can be expected. Comment: 216 pages
03/2009;
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of this work is to report first results of radiation effects induced by neutrons on epitaxial silicon devices with high resistivity. The epitaxial silicon material has been widely studied over the last few years (RD50…) and displays interesting performance regarding its eventual use in the PANDA pixel detector. Radiation damage measurement of some parameters of epitaxial diodes with three different epitaxial layer thickness have been performed for fluences corresponding to 1, 3 and 10 years of PANDA lifetime.
Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE; 11/2008
-
[show abstract]
[hide abstract]
ABSTRACT: The requirements for the PANDA Micro Vertex Detector in terms of track density and absence of a trigger signal lead to the need of a custom solution for the electronic readout of the silicon pixel detectors. A reduced scale prototype with two 128 cells and two 32 cells columns has been designed in a CMOS 0.13 μm technology and successfully tested. The ASIC measures the 2-D position, the hit arrival time and the charge released via a Time over Threshold technique.
Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE; 11/2008
