Intent to Publish 2006 IFF Results
Title:
Observation of di-hadron correlations in p\uparrow + p at sqrt{s} = 200 GeV
Principal Authors (alphabetical Order):
Keith Landry, Stephen Trentalange (UCLA), Anselm Vossen (IU), ....Intended Journal:
Phys. Rev. Lett.: The results are new and significant (first IFF in p+p, first transversity signal)
Abstract:
We report the fi rst signi cant signal from di-hadron correlations in p\uparrow + p collisions. The data
was taken using the STAR detector at BNL at \sqrt{s}= 200 during RHIC run6 in 2006. Di-hadron
correlations are thought to originate from the fragmentation of transversely polarized quarks via
the di-hadron interference fragmentation function (IFF) and are thus a direct probe of the quark
transversity distribution. The observed signal is the fi rst direct transversity measurement in p+p
collisions.
References:
(see attached paper draft for nicer formatting)[1] V. Barone, A. Drago, and P. G. Ratcli e, Phys.Rept. 359, 1 (2002), arXiv:hep-ph/0104283
[hep-ph].
[2] M. Anselmino, M. Boglione, U. D'Alesio, A. Kotzinian, F. Murgia, et al., Phys.Rev. D75,
054032 (2007), arXiv:hep-ph/0701006 [hep-ph].
[3] J. C. Collins, S. F. Heppelmann, and G. A. Ladinsky, Nucl.Phys. B420, 565 (1994), arXiv:hep-
ph/9305309 [hep-ph].
[4] A. Bianconi, S. Bo, R. Jakob, and M. Radici, Phys.Rev. D62, 034008 (2000), arXiv:hep-
ph/9907475 [hep-ph].
[5] A. Bacchetta, (2002), arXiv:hep-ph/0212025 [hep-ph].
[6] A. Vossen et al. (Belle Collaboration), Phys.Rev.Lett. 107, 072004 (2011), arXiv:1104.2425
[hep-ex].
[7] A. Airapetian et al. (HERMES Collaboration), JHEP 0806, 017 (2008), arXiv:0803.2367 [hep-
ex].
[8] C. Adolph et al. (COMPASS Collaboration), Phys.Lett. B713, 10 (2012), arXiv:1202.6150
[hep-ex].
[9] A. Bacchetta and M. Radici, Phys.Rev. D70, 094032 (2004), arXiv:hep-ph/0409174 [hep-ph].
[10] K. Ackermann et al. (STAR Collaboration), Nucl.Instrum.Meth. A499, 624 (2003).
[11] A. Bianconi, S. Bo, R. Jakob, and M. Radici, Phys.Rev. D62, 034009 (2000), arXiv:hep-
ph/9907488 [hep-ph].
[12] A. Bacchetta, A. Courtoy, and M. Radici, Phys. Rev. Lett. 107, 012001 (2011).
Figure 1: A_N as a function of M_Inv and P_T for eta <0 and eta > 0, cone cut of 0.3
Figure 2: A_N as a function of M_Inv and P_t for eta >0 with cone cuts of 0.2, 0.3 and 0.4
Figure 3: A_N as a function of eta
Figure 4: Trigger bias, shift of x with trigger condition in simulation
Conclusion:
In summary, STAR has detected the fi rst signal of transversity in p\uparrow + p collisions. The
presented results can be included in point-by-point extractions of transversity in a collinear
framework that are currently underway [12]. Compared with previous measurements of di-
hadron correlations in SIDIS, the RHIC data allows the access to a complementary kinematic
regime and proton-proton collisions do not suff er from u-quark dominance and will therefore
help constrain in particular the d-quark transversity. A large dataset taken in 2012 will
allow us to reduce the error bars on this measurement by about a factor of 3 and extracting asymmetries from hadron
pairs involving neutral pions will be investigated.
pairs involving neutral pions will be investigated.
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