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8,200 | Dilepton production from p-p to Ca-Ca at the Bevalac | nucl-ex | The DLS collaboration has recently completed a high statistics study of
dilepton production at the Bevalac. In particular, we have measured dielectrons
(e+e-) from p-p and p-d collisions to understand the basic dilepton production
mechanisms in the energy range from 1.05 - 4.9 GeV. These data can be used to
determine t... | physics |
8,201 | Measurement of Pion Enhancement at Low Transverse Momentum and of the Delta-Resonance Abundance in Si-Nucleus Collisions at AGS Energy | nucl-ex | We present measurements of the pion transverse momentum (p_t) spectra in
central Si-nucleus collisions in the rapidity range 2.0<y<5.0 for p_t down to
and including p_t=0. The data exhibit an enhanced pion yield at low p_t
compared to what is expected for a purely thermal spectral shape. This
enhancement is used to det... | physics |
8,202 | Charged Particle Pseudorapidity Distributions in Au+Al, Cu, Au, and U Collisions at 10.8 A$\cdot$GeV/c | nucl-ex | We present the results of an analysis of charged particle pseudorapidity
distributions in the central region in collisions of a Au projectile with Al,
Cu, Au, and U targets at an incident energy of 10.8~GeV/c per nucleon. The
pseudorapidity distributions are presented as a function of transverse energy
produced in the ... | physics |
8,203 | Radial Flow in Au+Au Collisions at E=0.25-1.15 A GeV | nucl-ex | A systematic study of energy spectra for light particles emitted at
midrapidity from Au+Au collisions at E=0.25-1.15 A GeV reveals a significant
non-thermal component consistent with a collective radial flow. This component
is evaluated as a function of bombarding energy and event centrality.
Comparisons to Quantum Mol... | physics |
8,204 | Onset of Collectivity in Neutron Deficient $^{196,198}$Po | nucl-ex | We have studied via in-beam $\gamma$-ray spectroscopy $^{196}$Po and
$^{198}$Po, which are the first neutron-deficient Po isotopes to exhibit a
collective low-lying structure. The ratios of yrast state energies and the E2
branching ratios of transitions from non-yrast to yrast states are indicative
of a low-lying vibra... | physics |
8,205 | Signatures of Statistical Decay | nucl-ex | The partition of decay energy between the kinetic energy of reaction products
and their Q-value of formation is obtained in a statistical derivation
appropriate to highly excited nuclei, and is shown to be in a constant ratio.
We measure the kinetic energy fraction, $R = \Sigma E_{kin}/(\Sigma E_{kin} +
\Sigma Q_0)$, o... | physics |
8,206 | Inclusive Electron Scattering from Nuclei at $x \simeq 1$ | nucl-ex | The inclusive A(e,e') cross section for $x \simeq 1$ was measured on $^2$H,
C, Fe, and Au for momentum transfers $Q^2$ from 1-7 (GeV/c)$^2$. The scaling
behavior of the data was examined in the region of transition from y-scaling to
x-scaling. Throughout this transitional region, the data exhibit $\xi$-scaling,
reminis... | physics |
8,207 | Spectroscopy of $^{194}$Po | nucl-ex | Prompt, in-beam $\gamma$ rays following the reaction $^{170}$Yb + 142 MeV
$^{28}$Si were measured at the ATLAS facility using 10 Compton-suppressed Ge
detectors and the Fragment Mass Analyzer. Transitions in $^{194}$Po were
identified and placed using $\gamma$-ray singles and coincidence data gated on
the mass of the e... | physics |
8,208 | Spin-rotor Interpretation of Identical Bands and Quantized Alignment in Superdeformed A $\approx$ 190 Nuclei | nucl-ex | The ``identical'' bands in superdeformed mercury, thallium, and lead nuclei
are interpreted as examples of orbital angular momentum rotors with the weak
spin-orbit coupling of pseudo-$SU(3)$ symmetries and supersymmetries. | physics |
8,209 | On the transverse momentum distribution of strange hadrons produced in relativistic heavy ion collisions | nucl-ex | Particles with strange quark content produced in the system 1.93 AGeV
$^{58}$Ni on $^{58}$Ni have been investigated at GSI Darmstadt with the FOPI
detector system. The correlation of these produced particles was analyzed with
respect to the reaction plane. Lambda baryons exhibit a very pronounced
sideward flow pattern ... | physics |
8,210 | Measurement of spin-dependent total cross-section difference $Δσ_T$ in neutron-proton scattering at 16 MeV | nucl-ex | A new measurement of $\Delta\sigma_T$ for polarized neutrons transmitted
through a polarized proton target at 16.2 MeV has been made. A polarized
neutron beam was obtained from the $^{3}\rm{H}(d,\vec n)^{4}\rm{He}$ reaction;
proton polarization over 90\% was achieved in a frozen spin target of 20 cm$^3$
volume. The mea... | physics |
8,211 | $^{6}$He + $α$ clustering in $^{10}$Be | nucl-ex | In a kinematically complete measurement of the
$^{7}$Li($^{7}$Li,$\alpha$$^{6}$He)$^4$He reaction at $E_{i}$ = 8 MeV it was
observed that the $^{10}$Be excited states at 9.6 and 10.2 MeV decay by
$^{6}$He emission. The state at 10.2 MeV may be a member of a rotational band
based on the 6.18 MeV 0$^+$ state. | physics |
8,212 | A Procedure to Calibrate a Multi-Modular Telescope | nucl-ex | A procedure has been developed for the charge, mass and energy calibration of
ions produced in nuclear heavy ion reactions. The charge and mass
identification are based on a $\Delta$E-E technique. A computer code determines
the conversion from ADC channels into energy values, atomic number and mass of
the detected frag... | physics |
8,213 | Calibration of Plastic Phoswich Detectors for Charged Particle Detection | nucl-ex | The response of an array of plastic phoswich detectors to ions of $1\le Z\le
18$ has been measured from $E/A$=12 to 72 MeV. The detector response has been
parameterized by a three parameter fit which includes both quenching and high
energy delta-ray effects. The fits have a mean variation of $\le 4\%$ with
respect to t... | physics |
8,214 | Bounds on new Majoron models from the Heidelberg-Moscow-Experiment | nucl-ex | In recent years several new Majoron models were invented to avoid
shortcomings of the classical models while leading to observable decay rates in
double beta experiments. We give the first experimental half life bounds on
double beta decays with new Majoron emission and derive bounds on the effective
neutrino--Majoron ... | physics |
8,215 | Superdeformation in $^{198}$Po | nucl-ex | The $^{174}$Yb($^{29}$Si,5n) reaction at 148 MeV with thin targets was used
to populate high-angular momentum states in $^{198}$Po. Resulting $\gamma$ rays
were observed with Gammasphere. A weakly-populated superdeformed band of 10
$\gamma$-ray transitions was found and has been assigned to $^{198}$Po. This is
the firs... | physics |
8,216 | Circumstantial Evidence for a Critical Behavior in Peripheral Au + Au Collisions at 35 MeV/nucleon | nucl-ex | The fragmentation resulting from peripheral Au + Au collisions at an incident
energy of E = 35 MeV/nucleon is investigated. A power-law charge distribution,
$A^{-\tau}$ with $\tau \approx 2.2$, and an intermittency signal are observed
for events selected in the region of the Campi scatter plot where "critical"
behavior... | physics |
8,217 | Multifragment production in Au+Au at 35 MeV/u | nucl-ex | Multifragment disintegration has been measured with a high efficiency
detection system for the reaction $Au + Au$ at $E/A = 35\ MeV$. From the event
shape analysis and the comparison with the predictions of a many-body
trajectories calculation the data, for central collisions, are compatible with
a fast emission from a... | physics |
8,218 | Statistical Multifragmentation in Central Au+Au Collisions at 35 MeV/u | nucl-ex | Multifragment disintegrations, measured for central Au + Au collisions at E/A
= 35 MeV, are analyzed with the Statistical Multifragmentation Model. Charge
distributions, mean fragment energies, and two-fragment correlation functions
are well reproduced by the statistical breakup of a large, diluted and
thermalized syst... | physics |
8,219 | SAMPLE: Parity Violating Electron Scattering from Hydrogen and Deuterium | nucl-ex | Recently, there has been considerable theoretical interest in determining
strange quark contributions to hadronic matrix elements. Such matrix elements
can be accessed through the nucleon's neutral weak form factors as determined
in parity violating electron scattering. The SAMPLE experiment will measure the
strange ma... | physics |
8,220 | A High Power Hydrogen Target for Parity Violation Experiments | nucl-ex | Parity-violating electron scattering measurements on hydrogen and deuterium,
such as those underway at the Bates and CEBAF laboratories, require
luminosities exceeding $10^{38}$cm$^{-2}$s$^{-1}$, resulting in large beam
power deposition into cryogenic liquid. Such targets must be able to absorb 500
watts or more with m... | physics |
8,221 | Signals of a Critical Behavior in Peripheral Au + Au Collisions at 35 MeV/nucleon | nucl-ex | Multifragment events resulting from peripheral Au + Au collisions at 35
MeV/nucleon are analysed in terms of critical behavior. The analysis of most of
criticality signals proposed so far (conditional moments of charge
distributions, Campi scatter plot, fluctuations of the size of the largest
fragment, intermittency an... | physics |
8,222 | Acceptance and resolution simulation studies for the dielectron spectrometer HADES at GSI | nucl-ex | Design studies for a second generation Dilepton Spectrometer to be built at
the SIS accelerator of GSI are presented. The basic design parameters of this
system are specified and the different detector components for charged particle
tracking and for lepton identification are described. The geometrical
acceptance for l... | physics |
8,223 | Test of Parity-Conserving Time-Reversal Invariance Using Polarized Neutrons and Nuclear Spin Aligned Holmium | nucl-ex | A test of parity-conserving, time-reversal non-invariance (PC TRNI) has been
performed in 5.9 MeV polarized neutron transmission through nuclear spin
aligned holmium. The experiment searches for the T-violating five-fold
correlation via a double modulation technique - flipping the neutron spin while
rotating the alignm... | physics |
8,224 | Universality of Spectator Fragmentation at Relativistic Bombarding Energies | nucl-ex | Multi-fragment decays of 129Xe, 197Au, and 238U projectiles in collisions
with Be, C, Al, Cu, In, Au, and U targets at energies between E/A = 400 MeV and
1000 MeV have been studied with the ALADIN forward-spectrometer at SIS. By
adding an array of 84 Si-CsI(Tl) telescopes the solid-angle coverage of the
setup was exten... | physics |
8,225 | Determination of Critical Exponents in Nuclear Systems | nucl-ex | Signatures of critical behaviour in nuclear fragmentation are often based on
arguments from percolation theory. We demonstrate with general thermodynamic
considerations and studies of the Ising model that the reliance on percolation
as a reference model bears the risk of missing parts of the essential physics. | physics |
8,226 | Last Minute from ALADIN: Temperature measurements in Au+Au reactions at relativistic energies | nucl-ex | We report on temperature measurements of nuclear systems formed in the Au+Au
collisions at incident energies of 50, 100, 150, 200 and 1000 A MeV. The target
spectator matter was studied at the highest energy and the interacting zone
(participants) at the lower ones.The temperature deduced from the isotope
ratios was co... | physics |
8,227 | The Nuclear Liquid-Gas Phase Transition: Present Status and Future Perspectives | nucl-ex | More than two decades ago, the van der Waals behavior of the nucleon -
nucleon force inspired the idea of a liquid-gas phase transition in nuclear
matter. Heavy-ion reactions at relativistic energies offer the unique
possibility for studying this phase transition in a finite, hadronic system. A
general overview of this... | physics |
8,228 | Scaling Laws and Transient Times in 3He Induced Nuclear Fission | nucl-ex | Fission excitation functions of compound nuclei in a mass region where shell
effects are expected to be very strong are shown to scale exactly according to
the transition state prediction once these shell effects are accounted for. The
fact that no deviations from the transition state method have been observed
within t... | physics |
8,229 | Charge correlations and dynamical instabilities in the multifragment emission process | nucl-ex | A new, sensitive method allows one to search for the enhancement of events
with nearly equal-sized fragments as predicted by theoretical calculations
based on volume or surface instabilities. Simulations have been performed to
investigate the sensitivity of the procedure. Experimentally, charge
correlations of intermed... | physics |
8,230 | Comment on "Circumstantial Evidence for Critical Behavior in Peripheral Au+Au Collisions at 35 MeV/nucleon" | nucl-ex | Mastinu et al. recently reported the observation of several positive signals
possibly indicating critical behavior in peripheral collisions of Au+Au at
$E/A$=35 MeV. In our comment, we examine the choice of variables used to
determine the presence (or absence) of critical behavior. We do this by
repeating the analysis ... | physics |
8,231 | The energy dependence of flow in Ni induced collisions from 400 to 1970A MeV | nucl-ex | We study the energy dependence of collective (hydrodynamic-like) nuclear
matter flow in 400-1970 A MeV Ni+Au and 1000-1970 A MeV Ni+Cu reactions. The
flow increases with energy, reaches a maximum, and then gradually decreases at
higher energies. A way of comparing the energy dependence of flow values for
different proj... | physics |
8,232 | Source size scaling of fragment production in projectile breakup | nucl-ex | Fragment production has been studied as a function of the source mass and
excitation energy in peripheral collisions of $^{35}$Cl+$^{197}$Au at 43
MeV/nucleon and $^{70}$Ge+$^{nat}$Ti at 35 MeV/nucleon. The results are
compared to the Au+Au data at 600 MeV/nucleon obtained by the ALADIN
collaboration. A mass scaling, b... | physics |
8,233 | Comment on ``Phase Coexistence in Multifragmentation'' | nucl-ex | This comment on Moretto et al.PRL 76:372,1996 argues that the IMF-charge
distribution may not be useful as signal for phase-transitions in nuclear
multifragmentation. Fluctuations of different origin may corrupt this signal.
Energy conservation is as important as charge conservation. The caloric
equation of state is mo... | physics |
8,234 | Measurements of the Total Cross Section for the Scattering of Polarized Neutrons from Polarized $^3$He | nucl-ex | Measurements of polarized neutron--polarized $^3$He scattering are reported.
The target consisted of cryogenically-polarized solid $^3$He, thickness 0.04
atom/b and polarization 40%. The longitudinal and transverse total
cross-section differences $\Delta\sigma_L$ and $\Delta\sigma_T$ were measured
for incident neutron ... | physics |
8,235 | Critical Behavior in Peripheral Au + Au Collisions at 35 MeV/u | nucl-ex | The signals theoretically predicted for the occurrence of a critical behavior
(conditional moments of charge distributions, Campi scatter plot, fluctuations
of the size of the largest fragment, power law in the charge distribution,
intermittency) have been found for peripheral events in the reaction Au+Au at
35 MeV/u. ... | physics |
8,236 | Scaling laws, transient times and shell effects in helium induced nuclear fission | nucl-ex | Fission excitation functions of He-3 and He-4 induced compound nuclei are
shown to scale exactly according to the Bohr-Wheeler transition state
prediction once the shell effects are accounted for. The presented method
furthermore allows one to model-independently extract values for the shell
effects which are in good a... | physics |
8,237 | The Role of Phase Space in Complex Fragment Emission from Low to Intermediate Energies | nucl-ex | The experimental emission probabilities of complex fragments by low energy
compound nuclei and their dependence upon energy and atomic number are compared
to the transition state rates. Intermediate-mass-fragment multiplicity
distributions for a variety of reactions at intermediate energies are shown to
be binomial and... | physics |
8,238 | Do phase transitions survive binomial reducibility and thermal scaling? | nucl-ex | First order phase transitions are described in terms of the microcanonical
and canonical ensemble, with special attention to finite size effects.
Difficulties in interpreting a "caloric curve" are discussed. A robust
parameter indicating phase coexistence (univariance) or single phase
(bivariance) is extracted for char... | physics |
8,239 | Statistical Binary Decay of $^{35}$Cl + $^{24}$Mg at 8 MeV/nucleon | nucl-ex | The properties of the two-body channels in the $^{35}$Cl + $^{24}$Mg reaction
at a bombarding energy of 275 MeV have been investigated by using
fragment-fragment coincident techniques. The exclusive data show that the
majority of events arises from a binary-decay process. The rather large number
of secondary light char... | physics |
8,240 | Pionic Fusion of Heavy Ions | nucl-ex | We report the first experimental observation of the pionic fusion of two
heavy ions. The 12C(12C,24Mg)pi0 and 12C(12C,24Na)pi+ cross sections have been
measured to be 208 +/- 38 and 182 +/- 84 picobarns, respectively, at E_cm = 137
MeV. This cross section for heavy-ion pion production, at an energy just 6 MeV
above the... | physics |
8,241 | Hadron yields and spectra in Au+Au collisions at the AGS | nucl-ex | Inclusive double differential multiplicities and rapidity density
distributions of hadrons are presented for 10.8 A GeV/c Au+Au collisions as
measured at the AGS by the E877 collaboration. The results indicate that large
amounts of stopping and collective transverse flow effects are present. The
data are also compared ... | physics |
8,242 | Characterization of nuclear physics targets using Rutherford backscattering and particle induced x-ray emission | nucl-ex | Rutherford backscattering and particle induced x-ray emission have been
utilized to precisely characterize targets used in nuclear fission experiments.
The method allows for a fast and non destructive determination of target
thickness, homogeneity and element composition. | physics |
8,243 | New Results on e+e- Line Emission in U+Ta Collisions | nucl-ex | We present new results obtained from a series of follow-up e+e- coincidence
measurements in heavy-ion collisions, utilizing an improved experimental set-up
at the double-Orange beta-spectrometer of GSI. The collision system U+Ta was
reinvestigated in three independent runs at beam energies in the range
(6.0-6.4)xA MeV ... | physics |
8,244 | Simulation studies of the HADES first level trigger PART I: Performance in heavy-ion induced reaction | nucl-ex | The first level trigger of the HADES spectrometer is studied for the
heavy-ion collision systems Au+Au and Ne+Ne. The trigger efficiency for central
events is given in dependence of the imposed charged particle multiplicity
condition. The timing properties of the trigger signal are described. The
losses due to deadtime... | physics |
8,245 | Simulation studies of the HADES first level trigger PART II: Performance in hadron induced reactions | nucl-ex | The HADES first level trigger is studied for the system p+Ni at a beam energy
of 2 AGeV. The timing properties of the trigger signal are reported. The
efficiency loss due to deadtime is specified. A trigger requirement of a time
overlap window with the start detector is described. The trigger rates for
different overla... | physics |
8,246 | Energy and Charged Particle Flow in 10.8 A GeV/c Au+Au Collisions | nucl-ex | Experimental results and a detailed analysis are presented of the transverse
energy and charged particle azimuthal distributions measured by the E877
collaboration for different centralities of Au+Au collisions at a beam momentum
of 10.8 A GeV/c. The anisotropy of these distributions is studied with respect
to the reac... | physics |
8,247 | Particle Production and Flow at SIS Energies | nucl-ex | An overview is given over recent measurements of flow and particle production
in the energy range from 0.1 to 2AGeV. Excitation functions for the directed
sideward and the azimuthally symmetric transverse flow are presented and show
the importance of flow phenomena in this incident energy regime. Rapidity
density distr... | physics |
8,248 | The Evolution of Nuclear Multifragmentation in the Temperature-Density Plane | nucl-ex | The mean transverse kinetic energies of the fragments formed in the
interaction of 1 A GeV Au+C have been determined. An energy balance argument
indicates the presence of a collective energy which increases in magnitude with
increasing multiplicity and accounts for nearly half of the measured mean
transverse kinetic en... | physics |
8,249 | Central Collisions of Au on Au at 150, 250 and 400 A MeV | nucl-ex | Collisions of Au on Au at incident energies of 150, 250 and 400 A MeV were
studied with the FOPI-facility at GSI Darmstadt. Nuclear charge (Z < 16) and
velocity of the products were detected with full azimuthal acceptance at
laboratory angles of 1-30 degrees. Isotope separated light charged particles
were measured with... | physics |
8,250 | Experimental Status of Parity Violating Electron Scattering | nucl-ex | Recently, there has been considerable theoretical interest in determining
strange quark contributions to hadronic matrix elements. Such matrix elements
can be accessed through the nucleon's neutral weak form factors as determined
in parity violating electron scattering. A program of experiments is presently
underway or... | physics |
8,251 | pi+ + d --> p + p reaction between 18 and 44 MeV | nucl-ex | A study of the reaction pi+ + d --> p + p has been performed in the energy
range of 18 - 44 MeV. Total cross sections and differential cross sections at
six angles have been measured at 15 energies with an energy increment of 1 - 2
MeV. This is the most systematic data set in this energy range. No structure in
the ener... | physics |
8,252 | Multifragmentation in Relativistic Heavy Ion Reactions | nucl-ex | Multifragmentation is the dominant decay mode of heavy nuclear systems with
excitation energies near their binding energies and is characterized by a
multiple production of nuclear fragments with intermediate mass.
At relativistic bombarding energies, multifragmentation may be observed in
peripheral collisions of hea... | physics |
8,253 | Direct experimental evidence of non-equilibrium energy sharing in dissipative collisions | nucl-ex | Primary and secondary masses of heavy reaction products have been deduced
from kinematics and E-ToF measurements, respectively, for the direct and
reverse collisions of 100Mo with 120Sn at 14.1 A MeV. Direct experimental
evidence of the correlation of energy-sharing with net mass transfer and
model-independent results ... | physics |
8,254 | The magnetic form factor of the neutron | nucl-ex | A review of neutron form factor measurements is given. We focus on recent
measurements of the neutron magnetic form factor $G_M^n$, and discuss in detail
our measurements of this quantity at momentum transfers Q^2=0.1-0.6 (GeV/c)^2. | physics |
8,255 | Stable Coulomb bubbles ? | nucl-ex | Coulomb bubbles, though stable against monopole displacement, are unstable at
least with respect to quadrupole and octupole distortions. We show that there
exists a temperature at which the pressure of the vapor filling the bubble
stabilizes all the radial modes. In extremely thin bubbles, the crispation
modes become u... | physics |
8,256 | MSX - A Monte-Carlo Code for Neutron Efficiency Calculations for Large Volume Gd-loaded Liquid Scintillation Detectors | nucl-ex | Some properties of the code newly developed to simulate the neutron detection
process in a neutron multiplicity meter are briefly described. | physics |
8,257 | e+e- pairs from 238U + 206Pb collisions | nucl-ex | We present the results from e+e- coincidence measurements in 238U + 206Pb
collisions at a beam energy of 5.93 MeV/u, using an improved experimental setup
at the double-Orange spectrometer of GSI. The capability of our device to
detect Internal-Pair-Conversion (IPC) e+e- pairs from discrete nuclear
transitions of a movi... | physics |
8,258 | Muon Catalyzed Fusion in 3 K Solid Deuterium | nucl-ex | Muon catalyzed fusion in deuterium has traditionally been studied in gaseous
and liquid targets. The TRIUMF solid-hydrogen-layer target system has been used
to study the fusion reaction rates in the solid phase of D_2 at a target
temperature of 3 K. Products of two distinct branches of the reaction were
observed; neutr... | physics |
8,259 | Pion-nucleus elastic scattering on 12C, 40Ca, 90Zr, and 208Pb at 400 and 500 MeV | nucl-ex | Pion-nucleus elastic scattering at energies above the Delta(1232) resonance
is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The
present data provide an opportunity to study the interaction of pions with
nuclei at energies where second-order corrections to impulse approximation
calculations should... | physics |
8,260 | Measurement of the Proton's Neutral Weak Magnetic Form Factor | nucl-ex | We report the first measurement of the parity-violating asymmetry in elastic
electron scattering from the proton. The asymmetry depends on the neutral weak
magnetic form factor of the proton which contains new information on the
contribution of strange quark-antiquark pairs to the magnetic moment of the
proton. We obta... | physics |
8,261 | Dielectron Cross Section Measurements in Nucleus-Nucleus Reactions at 1.0 A GeV | nucl-ex | We present measured dielectron production cross sections for Ca+Ca, C+C,
He+Ca, and d+Ca reactions at 1.0 A GeV. Statistical uncertainties and
systematic effects are smaller than in previous DLS nucleus-nucleus data. For
pair mass < 0.35 GeV/c2 : 1) the Ca+Ca cross section is larger than the
previous DLS measurement an... | physics |
8,262 | Comparison of low--energy resonances in 15N(alpha,gamma)19F and 15O(alpha,gamma)19Ne and related uncertainties | nucl-ex | A disagreement between two determinations of Gamma_alpha of the astro-
physically relevant level at E_x=4.378 MeV in 19F has been stated in two recent
papers by Wilmes et al. and de Oliveira et al. In this work the uncertainties
of both papers are discussed in detail, and we adopt the value
Gamma_alpha=(1.5^{+1.5}_{-0.... | physics |
8,263 | Breakup Temperature of Target Spectators in Au + Au Collisions at E/A = 1000 MeV | nucl-ex | Breakup temperatures were deduced from double ratios of isotope yields for
target spectators produced in the reaction Au + Au at 1000 MeV per nucleon.
Pairs of $^{3,4}$He and $^{6,7}$Li isotopes and pairs of $^{3,4}$He and H
isotopes (p, d and d, t) yield consistent temperatures after feeding
corrections, based on the ... | physics |
8,264 | Source Temperatures and Sizes in Central Collisions | nucl-ex | For midrapidity fragments from central 50-200 AMeV Au+Au collisions
temperatures from double ratios of isotopic yields were compared with
temperatures from particle unbound states. Temperatures from particle unbound
states with T = 4-5 MeV show with increasing beam energy an increasing
difference to temperatures from d... | physics |
8,265 | Emission temperatures and freeze out densities from light particle correlation functions in Au+Au collisions at 1 A GeV | nucl-ex | A study of emission temperatures extracted from excited state populations and
of freeze out radii from light particle intensity interferometry is presented.
Three high resolution dE-E-Hodoscopes with a total of 216 detectors are
combined with the ALADiN setup in order to study Au+Au collisions at 1 A GeV.
In contrast t... | physics |
8,266 | New Temperature Measurements in 197Au + 197Au Collisions | nucl-ex | We report on new measurements of breakup temperatures for target spectators
from 197Au + 197Au reactions at 1000 MeV per nucleon. The temperatures rise
with decreasing impact parameter from 4 MeV for peripheral to about 10 MeV for
the most central collisions, in good agreement with previous results for
projectile spect... | physics |
8,267 | Flow Phenomena at AGS Energies | nucl-ex | In this talk some of the latest data on directed sideward, elliptic, radial,
and longitudinal flow at AGS energies will be reviewed. A method to identify
the reaction plane event by event and the measurement of its resolution will be
discussed. The distributions of global observables (transverse energy E_T and
charged ... | physics |
8,268 | K^+ production in the reaction $^{58}Ni+^{58}Ni$ at incident energies from 1 to 2 AGeV | nucl-ex | Semi-inclusive triple differential multiplicity distributions of positively
charged kaons have been measured over a wide range in rapidity and transverse
mass for central collisions of $^{58}$Ni with $^{58}$Ni nuclei. The transverse
mass ($m_t$) spectra have been studied as a function of rapidity at a beam
energy 1.93 ... | physics |
8,269 | On the normalization of the HBT correlation function | nucl-ex | We discuss the question of the normalization of the correlation function and
its consistency with the often used form C(p1,p2) = 1+|f(p1,p2)|^2. We suggest
an event mixing method which allows one to obtain absolutely normalized
correlation functions from experimental data. | physics |
8,270 | First Energy and Angle differential Measurements of e^+e^- -pairs emitted by Internal Pair Conversion of excited Heavy Nuclei | nucl-ex | We present the first energy and angle resolved measurements of e+e- pairs
emitted from heavy nuclei (Z>=40) at rest by internal pair conversion (IPC) of
transitions with energies of less than 2MeV as well as recent theoretical
results using the DWBA method, which takes full account of relativistic
effects, magnetic sub... | physics |
8,271 | 3He- and 4He-induced nuclear fission - a test of the transition state method | nucl-ex | Fission in 3He and 4He induced reactions at excitation energies between the
fission barrier and 140 MeV has been investigated. Twentythree fission
excitation functions of various compound nuclei in different mass regions are
shown to scale exactly according to the transition state prediction once the
shell effects are ... | physics |
8,272 | Charged pions from Ni on Ni collisions between 1 and 2 AGeV | nucl-ex | Charged pions from Ni + Ni reactions at 1.05, 1.45 and 1.93 AGeV are measured
with the FOPI detector. The mean $\pi^{\pm}$ multiplicities per mean number of
participants increase with beam energy, in accordance with earlier studies of
the Ar + KCl and La + La systems. The pion kinetic energy spectra have concave
shape ... | physics |
8,273 | Open charm contribution to dilepton spectra produced in nuclear collisions at SPS energies | nucl-ex | Measurements of open charm hadro-production from CERN and Fermilab
experiments are reviewed, with particular emphasis on the absolute cross
sections and on their A and sqrt(s) dependences. Differential pt and xf cross
sections calculated with the Pythia event generator are found to be in
reasonable agreement with recen... | physics |
8,274 | Measurements of the reactions 12C + nu_e -> e- + 12N g.s. and 12C + nu_e -> e- + 12N | nucl-ex | Charged current reactions of nu_e on 12C have been studied using a mu
decay-at-rest nu_e beam from the Los Alamos Meson Physics Facility. More than
500 events from the exclusive reaction 12C + nu_e -> e- + 12N g.s. were
measured in a large Liquid Scintillator Neutrino Detector (LSND). The observed
energy dependence of ... | physics |
8,275 | Measurements of the reactions 12C + nu_mue -> mu- + 12N g.s. and 12C + nu_mu -> mue- + 12N | nucl-ex | Charged current scattering of nu_mu on 12C has been studied using a pi+
decay-in-flight nu_mu beam at the Los Alamos Meson Physics Facility. A sample
of 56.8 +- 9.6 events satisfying criteria for the exclusive reaction 12C +
nu_mu -> mu- + 12N_g.s. was obtained using the large Liquid Scintillator
Neutrino Detector (LSN... | physics |
8,276 | Abundance of Delta Resonances in 58Ni+58Ni Collisions between 1 and 2 AGeV | nucl-ex | Charged pion spectra measured in 58Ni-58Ni collisions at 1.06, 1.45 and 1.93
AGeV are interpreted in terms of a thermal model including the decay of Delta
resonances. The transverse momentum spectra of pions are well reproduced by
adding the pions originating from the Delta-resonance decay to the component of
thermal p... | physics |
8,277 | Double Beta Decays of Mo-100 and Nd-150 | nucl-ex | The double beta decays of Mo-100 and Nd-150 were studied in a time projection
chamber located 72 m underground. A 3275 h exposure of a 16.7 g sample of
metallic Mo enriched to 97.4 % in Mo-100 resulted in a two-neutrino half-life
of (6.82 + 0.38 - 0.53 +/- 0.68) * 10**18 y. Similarly, a 6287 h exposure of
15.5 g of Nd2... | physics |
8,278 | Protons, Deuterons and Flow | nucl-ex | Proton and deuteron m_T spectra and rapidity densities at y=1.9-2.3 are
presented for central SS, SPb and PbPb collisions. The inverse slopes increase
with system size and mass. The radius parameter, R_G, extracted from ratios of
the spectra increases with system size. R_G is proportional to 1/\sqrt{m_T}
consistent wit... | physics |
8,279 | Strangeness Production in Relativistic Heavy Ion Experiments | nucl-ex | The role of Strangeness as a signal of the Quark Gluon Plasma in relativistic
heavy ion experiments is discussed. The current experimental status is briefly
presented. Several scenarios which explain the CERN data are discussed. | physics |
8,280 | Weak e+e- lines from internal pair conversion observed in collisions of 238U with heavy nuclei | nucl-ex | We present the results of a Doppler-shift correction to the measured e+e-
sum-energy spectra obtained from e+e- coincidence measurements in 238U + 206Pb
and 238U + 181Ta collisions at beam energies close to the Coulomb barrier,
using an improved experimental setup at the double-Orange spectrometer of GSI.
Internal-Pair... | physics |
8,281 | A letter of intent for an experiment to measure nu_mu to nu_e oscillations and nu_mu disappearance at the Fermilab Booster (BooNE) | nucl-ex | This Letter of Intent to the Fermilab Program Advisory Committee describes a
search for neutrino oscillations at the Fermilab booster. It is motivated by
the LSND observation of nu_mu -> nu_e appearance. The booster neutrino
experiment (BooNE) will be capable of observing both nu_mu -> nu_e appearance
and nu_mu disappe... | physics |
8,282 | Stopping and Radial Flow in Central 58Ni + 58Ni Collisions between 1 and 2 AGeV | nucl-ex | The production of charged pions, protons and deuterons has been studied in
central collisions of 58Ni on 58Ni at incident beam energies of 1.06, 1.45 and
1.93 AGeV. The dependence of transverse-momentum and rapidity spectra on the
beam energy and on the centrality of the collison is presented. It is shown
that the scal... | physics |
8,283 | Proton and Pion Production Relative to the Reaction Plane in Au + Au Collisions at AGS Energies | nucl-ex | Results are presented of an analysis of proton and charged pion azimuthal
distributions measured with respect to the reaction plane in Au + Au collisions
at a beam momentum of about 11 AGeV/c. The azimuthal anisotropy is studied as a
function of particle rapidity and transverse momentum for different
centralities of th... | physics |
8,284 | Onset of Nuclear Matter Expansion in Au+Au Collisions | nucl-ex | Using the FOPI detector at GSI Darmstadt, excitation functions of collective
flow components were measured for the Au+Au system, in the reaction plane and
out of this plane, at seven incident energies ranging from 100AMeV to 800AMeV.
The threshold energies, corresponding to the onset of sideward-flow (balance
energy) a... | physics |
8,285 | Search for Exotic Strange Quark Matter in High Energy Nuclear Reactions | nucl-ex | We report on a search for metastable positively and negatively charged states
of strange quark matter in Au+Pb reactions at 11.6 A GeV/c in experiment E864.
We have sampled approximately six billion 10% most central Au+Pb interactions
and have observed no strangelet states (baryon number A < 100 droplets of
strange qua... | physics |
8,286 | Inclusive Dielectron Cross Sections in p+p and p+d Interactions at Beam Energies from 1.04 to 4.88 GeV | nucl-ex | Measurements of dielectron production in p+p and p+d collisions with beam
kinetic energies from 1.04 to 4.88 GeV are presented. The differential cross
section is presented as a function of invariant pair mass, transverse momentum,
and rapidity. The shapes of the mass spectra and their evolution with beam
energy provide... | physics |
8,287 | Search for extremely deformed fission fragment in ^{28}Si+^{28}Si with Eurogam Phase II | nucl-ex | A high-resolution study of fragment-fragment-$\gamma$ triple coincident
measurements of the symmetric-mass fission exit-channel from the
^{28}Si+^{28}Si reaction has been performed at the VIVITRON Tandem facility by
using the EUROGAM Phase II $\gamma$-ray spectrometer. The bombarding energy
E_{lab}(^{28}Si) = 111.6 MeV... | physics |
8,288 | Lambda Hyperons in 2 A*GeV Ni + Cu Collisions | nucl-ex | A sample of Lambda's produced in 2 A*GeV Ni + Cu collisions has been obtained
with the EOS Time Projection Chamber at the Bevalac. Low background in the
invariant mass distribution allows for the unambiguous demonstration of Lambda
directed flow. The transverse mass spectrum at mid-rapidity has the
characteristic shoul... | physics |
8,289 | Reduciblity, Arrhenius plots and the Uroboros Dragon, a reply to the preprint "Correlations in Nuclear Arrhenius-Type Plots" by M.B. Tsang and P. Danielewicz | nucl-ex | In a recent preprint by Tsang and Danielewicz, the authors attempt to give
alternative or trivial explanations for the reducible and "thermal" nature of
the intermediate mass fragment excitation functions reported previously (Phys.
Rev. Lett. 74, 1530 (1995), Phys. Lett B 361, 25 (1995), Phys. Rep. 287, 249
(1997)). We... | physics |
8,290 | Subthreshold K+ production in deuteron and alpha induced nuclear reactions | nucl-ex | Double differential cross sections have been measured for pi+ and K+ emitted
around midraidity in d+A and He+A collisions at a beam kinetic energy of 1.15
GeV/nucleon. The total pi+ yield increases by a factor of about 2 when using an
alpha projectile instead of a deuteron whereas the K+ yield increases by a
factor of ... | physics |
8,291 | A Measurement of the Interference Structure Function, R_LT, for the 12C(e,e'p) reaction in the Quasielastic Region | nucl-ex | The coincidence cross-section and the interference structure function, R_LT,
were measured for the 12C(e,e'p) 11B reaction at quasielastic kinematics and
central momentum transfer of q=400 MeV/c. The measurement was at an opening
angle of theta_pq=11 degrees, covering a range in missing energy of E_m = 0 to
65 MeV. The... | physics |
8,292 | Azimuthal Anisotropies as Stringent Test for Nuclear Transport Models | nucl-ex | Azimuthal distributions of charged particles and intermediate mass fragments
emitted in Au+Au collisions at 600AMeV have been measured using the FOPI
facility at GSI-Darmstadt. Data show a strong increase of the in-plane
azimuthal anisotropy ratio with the charge of the detected fragment.
Intermediate mass fragments ar... | physics |
8,293 | Antiproton Production in 11.5 A GeV/c Au+Pb Nucleus-Nucleus Collisions | nucl-ex | We present the first results from the E864 collaboration on the production of
antiprotons in 10% central 11.5 A GeV/c Au+Pb nucleus collisions at the
Brookhaven AGS. We report invariant multiplicities for antiproton production in
the kinematic region 1.4<y<2.2 and 50<p_T<300 MeV/c, and compare our data with
a first col... | physics |
8,294 | The $^4$He$(e,e'p)$ Cross Section at Large Missing Energy | nucl-ex | The $(e,e'p)$ reaction on $^{4}{He}$ nuclei was studied in kinematics
designed to emphasize effects of nuclear short-range correlations. The measured
cross sections display a peak in the kinematical regions where two-nucleon
processes are expected to dominate. Theoretical models incorporating
short-range correlation ef... | physics |
8,295 | Measurement of quasi-elastic 12C(p,2p) scattering at high momentum transfer | nucl-ex | We measured the high-momentum quasi-elastic 12C(p,2p) reaction (at center of
mass angle near 90 degrees) for 6 and 7.5 GeV/c incident protons. The
three-momentum components of both final state protons were measured and the
missing energy and momentum of the target proton in the nucleus were
determined.
The validity o... | physics |
8,296 | Measurements at low energies of the polarization-transfer coefficient Kyy' for the reaction 3H(p,n)3He at 0 degrees | nucl-ex | Measurements of the transverse polarization coefficient Kyy' for the reaction
3H(p,n)3He are reported for outgoing neutron energies of 1.94, 5.21, and 5.81
MeV. This reaction is important both as a source of polarized neutrons for
nuclear physics experiments, and as a test of theoretical descriptions of the
nuclear fou... | physics |
8,297 | Directed and Elliptic Flow in 158 GeV/Nucleon Pb + Pb Collisions | nucl-ex | The directed and elliptic flow of protons and charged pions has been observed
from the semi-central collisions of a 158 GeV/nucleon Pb beam with a Pb target.
The rapidity and transverse momentum dependence of the flow has been measured.
The directed flow of the pions is opposite to that of the protons but both
exhibit ... | physics |
8,298 | Fission Fragment Spectroscopy on a $^{28}$Si+$^{28}$Si Quasimolecular Resonance | nucl-ex | Fragment-fragment-$\gamma$ triple coincident measurements of the $^{28}$Si +
$^{28}$Si reaction at E$_{lab.}$ = 111.6 MeV carefully chosen to populate J =
38$^{+}$ resonance have been performed at the VIVITRON tandem facility by using
Eurogam Phase II $\gamma$-ray spectrometer. In the $^{28}$Si + $^{28}$Si
exit-channel... | physics |
8,299 | Reconstructing azimuthal distributions in nucleus-nucleus collisions | nucl-ex | Azimuthal distributions of particles produced in nucleus-nucleus collisions
are measured with respect to an estimated reaction plane which, because of
finite multiplicity fluctuations, differs in general from the true reaction
plane. It follows that the measured distributions do not coincide with the true
ones. I propo... | physics |
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