Japan Charged-Particle Nuclear Reaction Data Group
Division of Physics, Graduate School of Science
Hokkaido University
060-0810 Sapporo, JAPANE-mail: nrdf@jcprg.org
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Memo CP-E/051 (Revised)
Date:
To:
From:
Subject:
Reference:

August 30, 2004
Distribution
OTSUKA Naohiko
Differential data (Definition of mean energy and mean linear momentum)
CP-C/346, 348, 350, CP-D/409, CP-E/049

I appreciate the revision of LEXFOR entry in CP-C/350 and CP-D/409.
- Non-coplanar angular correlations:
Unit type of angular correlation function W(θ a ,θ b ,φ) should be ARB-UNITS rather than NODIM.
- Energy distribution for a correlated pair:“The angle is given …” should be “The energy is given…”.
What is the definition of mean energy E m given under E-MN-CM? Does it mean “energy ofrelative motion of correlated pair” (= center-of-mass energy) E rel ?
E rel = p rel 2/2μ2= p a 2/2m a + p b 2/2m b(in c.m.s. of correlated pair)(1), where momentum of relative motion p rel and reduced mass μ of correlated pair are defined asp rel = (m b p a – m a p b ) / (m a + m b )= pa = – pb
(in c.m.s. of correlated pair)(2)
μ = m a m b / (m a + m b )(3)
If so, alternative heading codes would be E-RL etc. We must avoid the confusion with “energyof outgoing particle given in center-of-mass system” (e.g. E-CM). c.f. CP-A/121. Examples of this energy distribution can be found in E1748.020-045. Note that E rel is Galilei invariant.
Concerning WP2002-5, I try to check the definition of “,ECO” (Energy correlation).
However I cannot find any entries of “,ECO” in our database.
- Linear momentum distribution:
Unit type should be DP rather than DA.

- Linear momentum for a correlated pair:“distribution” is needed between “momentum” and “for” in the title.
Unit type should be DP rather than DA.
What is the definition of mean linear momentum p m ? Does it mean “momentum of relativemotion” (| prel | given in Eq. (2)), or “momentum difference between two particles” | p a – p b |?
There would be alternative heading codes, e.g. MOM-SEC-RL for | prel |.
Concerning WP2002-5, I study the possibility of replacing MCO (Linear momentumcorrelation) by “DP,a+b”. Two subsections, M0035.022 and M0054.002, use this code:--M0035.022:
Data shown in Fig.4 of main reference gives counts as a function of momentum difference
between proton and neutron | p p – p n | for 4He(γ,p+n)2H (we can find the definition in p.934of the article). We could code M0035.002 using “,DP,N+P,REL” as a function ofmomentum difference given under appropriate data heading.
M0054.002 (I check the English translation Sov. J. Nucl. Phys.34 (1981) 789):
Data shown in Fig.1 of main reference gives counts as a function of | p d | = | p’ p + p’ n – p γ |for 12C(γ,p+n)10B, where p’ p and p’ n are the momenta of proton and neutron in 12C. These
momenta are obtained by applying final state interaction correction to measured momenta p pand p n (authors are interested in the momentum of quasi-deuterons in 12C). We could code
M0054.002 using ”,DP,D,REL” or “,DP,N+P,REL” as a function of momentum of quasideuterons | p d | given under MOM-SEC. In this case, the definition of this quasi-deuteron’s
momentum should be clarified under information identifier MOM-SEC.
Additional remark on M0054.002 :Fig.1 considers the correction of momenta due to final state interaction by assuming various
average depth for proton and neutron. In current compilation, heading E1 is assigned forthis potential depth and PAR is used in SF5. This is probably incorrect. Average depths
should be given under MISC, and PAR in SF5 should be removed.

Distribution:
S. Babykina, CAJaD
S. Dunaeva, NDS
A. Kaltchenko, KINR
M. Lammer, NDS
M.Mikhaylyukova, CJD
S. Takacs, ATOMKI
V. Varlamov, CDFE
V. Zerkin, NDS

J.H. Chang, KAERI
Z.G. Ge, CNDC
K. Katō, JCPRG
S. Maev, CJD
C. Nordborg, NEA-DB
S. Taova, VNIIEF
M. Vlasov, KINR
Y.X. Zhuang, CNDC

M. Chiba, JCPRG
O. Gritzay, KINR
M. Kellet, NEA-DB
V.N. Manokhin, CJD
P. Oblozinsky, NNDC
T. Tárkányi, ATOMKI
M. Wirtz, NDS
EXFOR, NEA-DB

F.E. Chukreev, CAJaD
A. Hasegawa, JAERI
M. Lammer, NDS
V. McLane, NNDC
O. Schwerer, NDS
V. Pronyaev, NDS
H.W. Yu, CNDC
JCPRG Distribution