Twist-3 fragmentation effects for ALT in light hadron production from proton–proton collisions
We compute the contribution from the twist-3 fragmentation function for light hadron production in collisions between transversely and longitudinally polarized protons, i.e., p↑p→→hX, which can cause a double-spin asymmetry (DSA) ALT. This is a naïve T-even twist-3 observable that we analyze in coll...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2016-01-01
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| Series: | Physics Letters B |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0370269315008618 |
| Summary: | We compute the contribution from the twist-3 fragmentation function for light hadron production in collisions between transversely and longitudinally polarized protons, i.e., p↑p→→hX, which can cause a double-spin asymmetry (DSA) ALT. This is a naïve T-even twist-3 observable that we analyze in collinear factorization using both Feynman gauge and lightcone gauge as well as give a general proof of color gauge invariance. So far only twist-3 effects in the transversely polarized proton have been studied for ALT in p↑p→→hX. However, there are indications that the naïve T-odd transverse single-spin asymmetry (SSA) AN in p↑p→hX is dominated not by such distribution effects but rather by a fragmentation mechanism. Therefore, one may expect similarly that the fragmentation contribution is important for ALT. Given possible plans at RHIC to measure this observable, it is timely to provide a calculation of this term. |
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| ISSN: | 0370-2693 1873-2445 |