arXiv subjects

H. M. Staudenmaier

Publications and source records attributed to H. M. Staudenmaier.

8 recordsLinked to original sources

arXiv2010

Measurement of $K^- p$ radiative capture to $γΛ$ and $γΣ^0$ for $p_{K^-}$ between 514 and 750 MeV/$c$

Differential cross sections for $K^-$ radiative capture in flight on the proton, leading to the $γΛ$ and $γΣ^0$ final states, have been measured at eight $K^-$ momenta between 514 and 750 MeV/$c$. The data were obtained with the Crystal Ball multiphoton spectrometer installed at the separated $K/π$ beam line C6 of the BNL Alternating Gradient Synchrotron. The results substantially improve the existing experimental data available for studying radiative decays of excited hyperon states. An exploratory theoretical analysis is performed within the Regge-plus-resonance approach. According to this analysis, the $γΣ^0$ final state is dominated by hyperonresonance exchange and hints at an important role for a resonance in the mass region of 1700 MeV. In the $γΛ$ final state, on the other hand, the resonant contributions account for only half the strength, and the data suggest the importance of a resonance in the mass region of 1550 MeV.

hep-ex↗

arXiv2009

Differential cross sections of the charge-exchange reaction pi- p --> pi0 n in the momentum range from 103 to 178 MeV/c

Measured values of the differential cross sections for pion-nucleon charge exchange, pi- p --> pi0 n, are presented for pi- momenta of 103, 112, 120, 130, 139, 152, and 178 MeV/c. Complete angular distributions were obtained by using the Crystal Ball detector at the Alternating Gradient Synchrotron at Brookhaven National Laboratory. Statistical uncertainties of the differential cross sections vary from 3% to 6% in the backward angle region, and from 6% to about 20% in the forward region with the exception of the two most forward angles. The systematic uncertainties are estimated to be about 3% for all momenta.

hep-ex↗

arXiv2009

Measurement of $π^0 Λ$, $\bar{K}^0 n$, and $π^0 Σ^0$ production in $K^- p$ interactions for $p_{K^-}$ between 514 and 750 MeV/$c$

Differential cross sections and hyperon polarizations have been measured for $\bar{K}^0 n$, $π^0 Λ$, and $π^0 Σ^0$ production in $K^- p$ interactions at eight $K^-$ momenta between 514 and 750 MeV/$c$. The experiment detected the multiphoton final states with the Crystal Ball spectrometer using a $K^-$ beam from the Alternating Gradient Synchrotron of BNL. The results provide significantly greater precision than the existing data, allowing a detailed reexamination of the excited hyperon states in our energy range.

hep-ex↗

arXiv2005

ParFORM: recent development

We report on the status of our project of parallelization of the symbolic manipulation program FORM. We have now parallel versions of FORM running on Cluster- or SMP-architectures. These versions can be used to run arbitrary FORM programs in parallel.

cs.SC↗

arXiv2004

ParFORM: Parallel Version of the Symbolic Manipulation Program FORM

After an introduction to the sequential version of FORM and the mechanisms behind, we report on the status of our project of parallelization. We have now a parallel version of FORM running on Cluster- and SMP-architectures. This version can be used to run arbitrary FORM programs in parallel.

cs.SC↗

arXiv2004

Measurement of Inverse Pion Photoproduction at Energies Spanning the N(1440) Resonance

Differential cross sections for the process pi^- p -> gamma n have been measured at Brookhaven National Laboratory's Alternating Gradient Synchrotron with the Crystal Ball multiphoton spectrometer. Measurements were made at 18 pion momenta from 238 to 748 MeV/c, corresponding to E_gamma for the inverse reaction from 285 to 769 MeV. The data have been used to evaluate the gamma n multipoles in the vicinity of the N(1440) resonance. We compare our data and multipoles to previous determinations. A new three-parameter SAID fit yields 36 +/- 7 (GeV)^-1/2 X 10^-3 for the A^n_1/2 amplitude of the P_11.

nucl-ex↗

arXiv2004

Does the Sigma(1580)3/2- resonance exist?

Precise new data for the reaction $K^- p \to π^0 Λ$ are presented in the c.m. energy range 1565 to 1600 MeV. Our analysis of these data sheds new light on claims for the $Σ(1580){3/2}^-$ resonance, which (if it exists with the specified quantum numbers) must be an exotic baryon because of its very low mass. Our results show no evidence for this state.

nucl-ex↗

arXiv2002

Meson production on complex nuclei by pi^- with the Crystal Ball detector

We report on preliminary results for the production of neutral mesons by 750 MeV/$c$ $π^-$ on complex nuclear targets (C, Al, Cu) and hydrogen. Our simultaneous measurement of $π^0$, $2π^0$, and $η$ final states allows an investigation of the nuclear final-state-interaction effects. The data show that nuclear absorption is mainly responsible for an observed change in the shape of the $2π^0$ invariant mass spectra. Our preliminary result for the $σ\to γγ$ branching ratio is BR$(σ\to γγ) < 3.6\times 10^{-3} \times ϕ$ at 90% C.L. on a carbon target, where $ϕ$ is the fraction of $2π^0$ produced via the $σ$ intermediate state.

nucl-ex↗