Single spin asymmetry in forward <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mi>A</mml:mi></mml:math> collisions from the Pomeron-odderon interference

Working in the hybrid framework of the high energy <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>p</a:mi><a:mi>A</a:mi></a:math> collisions we identify a new contribution to transverse single spin asymmetry (SSA). The phase necessary for the SSA is provided by the Pomeron-odderon interference in the dense nuclear target. The complete formula for the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>p</c:mi><c:mi>A</c:mi><c:mo stretchy="false">→</c:mo><c:mi>h</c:mi><c:mi>X</c:mi></c:math> polarized cross section also contains the transversity distribution for the polarized projectile as well as the real part of the twist-three fragmentation function. We numerically estimate the asymmetry <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:msub><f:mi>A</f:mi><f:mi>N</f:mi></f:msub></f:math> and its nuclear dependence. Based on a model computation we find that <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:msub><h:mi>A</h:mi><h:mi>N</h:mi></h:msub></h:math> can be a percent level in the forward and low-<j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:msub><j:mi>P</j:mi><j:mrow><j:mi>h</j:mi><j:mo>⊥</j:mo></j:mrow></j:msub></j:math> region. For large nuclei we find significant suppression, with <l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:msub><l:mi>A</l:mi><l:mi>N</l:mi></l:msub><l:mo>∝</l:mo><l:msup><l:mi>A</l:mi><l:mrow><l:mo>−</l:mo><l:mn>7</l:mn><l:mo>/</l:mo><l:mn>6</l:mn></l:mrow></l:msup></l:math> parametrically. As a notable feature we find a node of <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"><n:msub><n:mi>A</n:mi><n:mi>N</n:mi></n:msub></n:math> as a function of the <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:msub><p:mi>P</p:mi><p:mrow><p:mi>h</p:mi><p:mo>⊥</p:mo></p:mrow></p:msub></p:math> around the values of the initial saturation scale that could be used to test this mechanism experimentally.