The straw tube trackers of the PANDA experiment Gianotti, P.; Lucherini, V.; Pace, E. ...
2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications (ANIMMA),
06/2013
Conference Proceeding
Odprti dostop
The P̅ANDA experiment will be built at the FAIR facility at Darmstadt (Germany) to perform accurate tests of the strong interaction through p̅p and p̅A annihilation's studies. To track charged ...particles, two systems consisting of a set of planar, closed-packed, self-supporting straw tube layers are under construction. The P̅ANDA straw tubes will have also unique characteristics in term of material budget and performance. They consist of very thin mylar-aluminized cathodes which are made self-supporting by means of the operation gas-mixture over-pressure. This solution allows to reduce at maximum the weight of the mechanical support frame and hence the detector material budget. The P̅ANDA straw tube central tracker will not only reconstruct charged particle trajectories, but also will help in low momentum (<; 1 GeV) particle identification via dE/dx measurements. This is a quite new approach that P̅ANDA tracking group has first tested with detailed Monte Carlo simulations, and then with experimental tests of detector prototypes. This paper addresses the design issues of the P̅ANDA straw tube trackers and the performance obtained in prototype tests.
We report the results from a study of the full sample of 66.03110 super(7) K super(c)1p super(c) p super(0) p super(0) decays recorded by the NA48/2 experiment at the CERN SPS. As first observed in ...this experiment, the p super(0) p super(0) invariant mass (M sub(00)) distribution shows a cusp-like anomaly in the region around M sub(00)=2m sub(+), where m sub(+) is the charged pion mass. This anomaly has been interpreted as an effect due mainly to the final state charge exchange scattering process p super(+) p super(-)1p super(0) p super(0) in K super(c)1p super(c) p super(+) p super(-) decay. Fits to the M sub(00) distribution using two different theoretical formulations provide the presently most precise determination of a sub(0)-a sub(2), the difference between the p p S-wave scattering lengths in the isospin I=0 and I=2 states. Higher-order p p rescattering terms, included in the two formulations, allow also an independent, though less precise, determination of a sub(2).
Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an ...unparalleled factory for various hyperon–antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P‾ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ−-atoms will be feasible and even the production of Ω−-atoms will be within reach. The latter might open the door to the |S|=3 world in strangeness nuclear physics, by the study of the hadronic Ω−-nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions.
Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of ...hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion (
πN
) TDAs from
reaction with the future P̄ANDA detector at the FAIR facility. At high center-of-mass energy and high invariant mass squared of the lepton pair
q
2
, the amplitude of the signal channel
admits a QCD factorized description in terms of
πN
TDAs and nucleon Distribution Amplitudes (DAs) in the forward and backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring
with the P̄ANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel,
i.e.
were performed for the center-of-mass energy squared
s
= 5 GeV
2
and
s
= 10 GeV
2
, in the kinematic regions 3.0 <
q
2
< 4.3 GeV
2
and 5 <
q
2
GeV
2
, respectively, with a neutral pion scattered in the forward or backward cone
in the proton-antiproton center-of-mass frame. Results of the simulation show that the particle identification capabilities of the P̄ANDA detector will allow to achieve a background rejection factor of 5 · 10
7
(1 · 10
7
) at low (high)
q
2
for
s
= 5 GeV
2
, and of 1 · 10
8
(6 · 10
6
) at low (high)
q
2
for
s
= 10 GeV
2
, while keeping the signal reconstruction efficiency at around 40%. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 fb
−1
of integrated luminosity. The cross sections obtained from the simulations are used to show that a test of QCD collinear factorization can be done at the lowest order by measuring scaling laws and angular distributions. The future measurement of the signal channel cross section with P̄ANDA will provide a new test of the perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing
π
TDAs.
Triple GEM performance in magnetic field Alexeev, M.; Amoroso, A.; Bagnasco, S. ...
Journal of instrumentation,
08/2019, Letnik:
14, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Performance of triple GEM prototypes in strong magnetic field has been evaluated by means of a muon beam at the H4 line of the SPS test area at CERN. Data have been reconstructed and analyzed offline ...with two reconstruction methods: the charge centroid and the micro-Time-Projection-Chamber exploiting the charge and the time measurement respectively. Depending on the combination of the particle incident angle and magnetic filed, there's always one of the two algorithms achieving a spatial resolution of 100–120 μm.
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