5,924 research outputs found
Simplification of the DREAM collaboration's "Q/S method" in dual readout calorimetry analysis
The DREAM collaboration has introduced the "Q/S Method" for obtaining the
energy estimator from simultaneous Cherenkov and scintillator readouts of
individual hadronic events. We show that the algorithm is equivalent to an
elementary method
Hadron detection with a dual-readout fiber calorimeter
In this paper, we describe measurements of the response functions of a
fiber-based dual- readout calorimeter for pions, protons and multiparticle
"jets" with energies in the range from 10 to 180 GeV. The calorimeter uses lead
as absorber material and has a total mass of 1350 kg. It is complemented by
leakage counters made of scintillating plastic, with a total mass of 500 kg.
The effects of these leakage counters on the calorimeter performance are
studied as well. In a separate section, we investigate and compare different
methods to measure the energy resolution of a calorimeter. Using only the
signals provided by the calorimeter, we demonstrate that our dual-readout
calorimeter, calibrated with electrons, is able to reconstruct the energy of
proton and pion beam particles to within a few percent at all energies. The
fractional widths of the signal distributions for these particles (sigma/E)
scale with the beam energy as 30%/sqrt(E), without any additional contributing
terms
ILC Beam Energy Measurement by means of Laser Compton Backscattering
A novel, non-invasive method of measuring the beam energy at the
International Linear Collider is proposed. Laser light collides head-on with
beam particles and either the energy of the Compton scattered electrons near
the kinematic end-point is measured or the positions of the Compton
backscattered -rays, the edge electrons and the unscattered beam
particles are recorded. A compact layout for the Compton spectrometer is
suggested. It consists of a bending magnet and position sensitive detectors
operating in a large radiation environment. Several options for high spatial
resolution detectors are discussed. Simulation studies support the use of an
infrared or green laser and quartz fiber detectors to monitor the backscattered
photons and edge electrons. Employing a cavity monitor, the beam particle
position downstream of the magnet can be recorded with submicrometer precision.
Such a scheme provides a feasible and promising method to access the incident
beam energy with precisions of or better on a bunch-to-bunch basis
while the electron and positron beams are in collision.Comment: 47 pages, 26 figures, version as accepted by Nucl. Instr. Meth. A
after improvement
The high-energy hadron spin-flip amplitude at small momentum transfer and new AN data from RHIC
In the case of elastic high-energy hadron-hadron scattering, the impact of
the large-distance contributions on the behaviour of the slopes of the
spin-non-flip and of the spin-flip amplitudes is analysed. It is shown that the
long tail of the hadronic potential in impact parameter space leads to a value
of the slope of the reduced spin-flip amplitude larger than that of the
spin-non-flip amplitude. This effect is taken into account in the calculation
of the analysing power in proton-nucleus reactions at high energies. It is
shown that the preliminary measurement of AN obtained by the E950 Collaboration
indeed favour a spin-flip-amplitude with a large slope. Predictions for AN at
pL = 250 GeV/c are given.Comment: 16 pages, 5 figures, a few typos fixed in v.
Is there exist a hadron spin-flip contribution in the Coulomb-hadron interference at small transfer momenta and high energies
The analysing power is examined in the range of the Coulomb-hadron
interferenceon on the basis of the experimental data from p_L = 6 GeV/c up to
200 GeV/c taking account of a phenomenological analysis at p_L = 6 GeV/c and a
dynamic high-energy spin model. The results are compared with the new RHIC data
at p_L = 100 GeV/c. The new experimental data obtained at RHIC indicate the
small contributions of the hadrons spin-flip amplitude.Comment: 18 pages, 8 figures, Table Essentially revision. Figures and Table
are added, fit with new final data are made. Conclusion is not chang
Form of analyzing power and the determination of the basic parameters of hadron scattering amplitude
The determination of magnitudes of basic parameters of the high energy
elastic scattering amplitude are examined at small momentum transfers with
taking account of the Coulomb-hadron interference effects.Comment: 6 pages, LaTeX, 4 figures (files.ps), Talk at the International
Workshop "Spin and Symmetry" (Prague, Chech., 13-19 July 2000
Dual-Readout Calorimetry with Lead Tungstate Crystals
Results are presented of beam tests in which a small electromagnetic
calorimeter consisting of lead tungstate crystals was exposed to 50 GeV
electrons and pions. This calorimeter was backed up by the DREAM Dual-Readout
calorimeter, which measures the scintillation and \v{C}erenkov light produced
in the shower development, using two different media. The signals from the
crystal calorimeter were analyzed in great detail in an attempt to determine
the contributions from these two types of light to the signals, event by event.
This information makes it possible to eliminate the dominating source of
fluctuations and thus achieve an important improvement in hadronic calorimeter
performance.Comment: Preprint submitted to Nucl. Instrum. Meth. on July 23, 200
Energy Dependence of the Pomeron Spin-Flip
There is no theoretical reason to think that the spin-flip component of the
Pomeron is zero. One can measure the spin-flip part using Coulomb-nuclear
interference (CNI). Perturbative QCD calculations show that the spin-flip
component is sensitive to the smallest quark separation in the proton, while
the non-flip part probes the largest separation. According to HERA results on
the proton structure function at very low x the energy dependence of the
cross-section correlates with the size of the color dipole. Analysing the data
from HERA we predict that the ratio of the spin-flip to non-flip amplitude
grows with energy as , violating Regge
factorisation of the Pomeron.Comment: A few comments and references are added. Based on invited talks at
the International Workshop on Diffraction Physics, Rio de Janeiro, February
16-20, 1998, and at DIS'98, Brussels, April 4-8, 199
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