TY - GEN
T1 - Precision measurement of the neutron's beta asymmetry using ultra-cold neutrons
AU - Makela, M.
AU - Back, H. O.
AU - Melconian, D.
AU - Plaster, B.
PY - 2006
Y1 - 2006
N2 - A measurement of Aβ, the correlation between the electron momentum and neutron (n) spin (the beta asymmetry) in n beta-decay, together with the n lifetime, provides a method for extracting fundamental parameters for the charged-current weak interaction of the nucleon. In particular when combined with decay measurements, one can extract the Vud element of the CKM matrix, a critical element in CKM unitarity tests. By using a new SD2 super-thermal source at LANSCE, large fluxes of UCN (ultra-cold neutrons) are expected for the UCNA project. These UCN will be 100% polarized using a 7 T magnetic field, and directed into the β spectrometer. This approach, together with an expected large reduction in backgrounds, will result in an order of magnitude reduction in the critical systematic corrections associated with current n β-asymmetry measurements. This paper will give an overview of the UCNA Aβ measurement as well as an update on the status of the experiment.
AB - A measurement of Aβ, the correlation between the electron momentum and neutron (n) spin (the beta asymmetry) in n beta-decay, together with the n lifetime, provides a method for extracting fundamental parameters for the charged-current weak interaction of the nucleon. In particular when combined with decay measurements, one can extract the Vud element of the CKM matrix, a critical element in CKM unitarity tests. By using a new SD2 super-thermal source at LANSCE, large fluxes of UCN (ultra-cold neutrons) are expected for the UCNA project. These UCN will be 100% polarized using a 7 T magnetic field, and directed into the β spectrometer. This approach, together with an expected large reduction in backgrounds, will result in an order of magnitude reduction in the critical systematic corrections associated with current n β-asymmetry measurements. This paper will give an overview of the UCNA Aβ measurement as well as an update on the status of the experiment.
KW - CKM unitarity
KW - Neutron beta asymmetry
KW - Ultra-cold neutron source
UR - http://www.scopus.com/inward/record.url?scp=33846339152&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846339152&partnerID=8YFLogxK
U2 - 10.1063/1.2220389
DO - 10.1063/1.2220389
M3 - Conference contribution
AN - SCOPUS:33846339152
SN - 0735403384
SN - 9780735403383
T3 - AIP Conference Proceedings
SP - 808
EP - 810
BT - PARTICLES AND NUCLEI
T2 - PARTICLES AND NUCLEI: Seventeenth Internatinal Conference on Particles and Nuclei
Y2 - 23 October 2005 through 30 October 2005
ER -