120047394
Quark fragmentation to pions and kaons in the NJL‐jet model
We describe the quark fragmentation functions to pions and kaons in the NJL‐jet model and compare the results with empirical parametrizations. By including cascade‐like fragmentation processes, the momentum and isospin sum rules can be satisfied naturally without introducing new parameters into the theory. We associate a low energy scale with the NJL model, and perform the Q2 evolution in leading order. The results are in reasonable agreement with the empirical fragmentation functions.
18357270
Quark distributions in nucleons and nuclei
We discuss the medium modifications of quark distributions and structure functions in the framework of a chiral effective quark theory. Particular emphasis is put on the isospin dependence of the in-medium quark distributions. As an interesting application, we discuss a possible solution of the so called NuTeV anomaly. Possible extensions of the model to describe fragmentation functions are also discussed.
119264092
Spin-dependent parton distributions and structure functions
Nuclear parton distributions and structure functions are determined in an effective chiral quark theory. We also discuss an extension of our model to fragmentation functions.
118654202
Neutron Beta Decay Studies with Nab
Precision measurements in neutron beta decay serve to determine the coupling constants of beta decay and allow for several stringent tests of the standard model. This paper discusses the design and the expected performance of the Nab spectrometer.
121871688
Antiproton trapping in various helium media: report of the HELIUMTRAP experiment at LEAR
Abstract HELIUMTRAP (PS205) investigates the recently discovered anomalously long-lived states of antiprotons in various helium media. An overview is given of experiments stopping antiprotons in several phases of helium performed at LEAR in the last two years.
122256238
Kaonic hydrogen X-ray experiment at KEK
Abstract For the further understanding of the K -N interaction in the low energy region, we are performing a measurement of K − p X rays at KEK which adopts a new technique to improve the signal-to-background ratio (S/N); specifying the final state of the K − p reaction and using a gaseous hydrogen target (4 atm at 100 K). With this technique three orders of magnitude better S/N and one order higher statistics are expected as compared to previous experiments.
287995
A multiwire proportional chamber for precision studies of neutron β decay angular correlations
Abstract A new multiwire proportional chamber (MWPC) was designed and constructed for precision studies of neutron β decay angular correlations. Its design has several novel features, including the use of low pressure neopentane as the MWPC gas and an entrance window made of thin Mylar sheet reinforced with Kevlar fibers. In the initial off-line performance tests, the gas gain of neopentane and the position resolution were studied.
20143159
Measurements of ultracold-neutron lifetimes in solid deuterium.
We present the first measurements of the survival time of ultracold neutrons (UCNs) in solid deuterium (SD2). This critical parameter provides a fundamental limitation to the effectiveness of superthermal UCN sources that utilize solid ortho-deuterium as the source material. These measurements are performed utilizing a SD2 source coupled to a spallation source of neutrons, providing a demonstration of UCN production in this geometry and permitting systematic studies of the influence of thermal up-scatter and contamination with para-deuterium on the UCN survival time.