References - Bogoliubov Laboratory of Theoretical Physics - JINR

Table 1: Status of the DY experiments
Experiment Status Remarks
CERN: E615 Finished Fixed target mode. Unpolarized target and beam
CERN: NA10,38,50 Finished Fixed target mode. Unpolarized tergat and beam
FERMILAB: E886,906 Running Fixed target mode. Unpolarized target and beam
RHIC: STAR,PHENIX Running up to ? Collider mode. Detector upgrade for DY studies
polarized beams
GSI: PANDA Plan > 2016 Fixed target mode. Unpolarized
GSI: PAX Plan > 2016 Collider mode. Polarized beams.
Problem with anti-proton beam polarization
CERN: COMPASS Plan > 2011 Fixed target mode. Polarized beam.
Valence PDFs
J-PARC Plan > 2011 Fixed target mode. Unpolarized beam and
target, s ∼ 60 − 100GeV 2
SPASCHARM Plan ? Fixed target mode. Unpolarized beam and
target, s ∼ 140GeV 2 2
SPD-NICA Plan > 2014 Collider mode. s ∼ 670GeV 2 ,high
luminosity, polarized proton and deuteron
beams, energy scan.
Table 2: The estimation of the cross-sections and number of DY events for NICA and PAX kinematics
σDY total, nb L, cm −2 s −1 Thousands events
PAX, √ s =14.6GeV ∼ 2 ∼ 10 3 0 ∼ 10
NICA, √ s =20GeV ∼ 1 ∼ 10 3 0 ∼ 5
PAX, √ s =26GeV ∼ 1.3 ∼ 10 3 0 ∼ 7
– J/ψ production processes with unpolarized and single polarized pp and pd
collisions, which can not be completely duplicated by other experiments (COMPASS [1],
RHIC [2], PAX [3] and J-PARC [4], as it is seen from Table 1.
First, at COMPASS and J-PARC the fixed target mode with unpolarized beam and
polarized target is only possible. As it will be shown later, for this option the transversity
and Boer-Mulders PDFs are hardly accessible for pp and pd collisions. COMPASS can
reach the transversity via π − p collisions. However, in this case the unknown pion PDFs
will be involved, introducing the additional theoretical uncertainty [5].
Second, PAX plans to access transversity via measurements of double polarized DY
processes, which will very difficult because of the antiproton polarization problems [3].
Third, the RHIC experiments cover the kinematical region different from the respective
region covered by NICA.
Fourth, the advantage of NICA in comparison with all above mentioned experiments
is that only NICA can provide an access to transversity, Boer-Mulders and Sivers PDFs
for both u and d flavors.
The Table 2 shows the estimation of the cross-sections and possible statistics for DY
events, which can be collected with SPD at NICA during one month in comparison with
those from the PAX proposal.
To estimate the possible precision of measurements of the asymmetries the set of
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