Single isolated photon production in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mtext>NL</mml:mtext><mml:msup><mml:mrow><mml:mtext>O</mml:mtext></mml:mrow><mml:mrow><mml:mo>*</mml:mo></mml:mrow></mml:

The hadroproduction of single isolated photon at high energies is studied within the framework of the next-to-leading order (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msup><a:mrow><a:mi>NLO</a:mi></a:mrow><a:mrow><a:mo>⋆</a:mo></a:mrow></a:msup></a:mrow></a:math>) approximation of the parton Reggeization approach based on the modified multi-Regge limit of the hard scattering quantum chromodynamics (QCD) amplitudes. The contribution from the LO subprocess <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>Q</c:mi><c:mover accent="true"><c:mi>Q</c:mi><c:mo stretchy="false">¯</c:mo></c:mover><c:mo stretchy="false">→</c:mo><c:mi>γ</c:mi></c:math> and the NLO tree-level corrections <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:mi>Q</h:mi><h:mi>R</h:mi><h:mo stretchy="false">→</h:mo><h:mi>γ</h:mi><h:mi>q</h:mi></h:math> and <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mi>Q</k:mi><k:mover accent="true"><k:mi>Q</k:mi><k:mo stretchy="false">¯</k:mo></k:mover><k:mo stretchy="false">→</k:mo><k:mi>γ</k:mi><k:mi>g</k:mi></k:math> are considered. To avoid specific double counting in rapidity between tree-level corrections to the hard scattering coefficient and unintegrated PDFs, a corresponding subtraction scheme is proposed. We demonstrated self-consistency of the parton Reggeization approach using the subtraction scheme. The results of calculations are compared with data from various collaborations in the wide energy range <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:mrow><p:msqrt><p:mrow><p:mi>S</p:mi></p:mrow></p:msqrt><p:mo>=</p:mo><p:mn>24</p:mn><p:mtext> </p:mtext><p:mtext> </p:mtext><p:mi>GeV</p:mi><p:mi>–</p:mi><p:mn>13</p:mn><p:mtext> </p:mtext><p:mtext> </p:mtext><p:mi>TeV</p:mi></p:mrow></p:math>. We obtained a quite satisfactory agreement with data up to <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"><r:mrow><r:msubsup><r:mrow><r:mi>p</r:mi></r:mrow><r:mrow><r:mi>T</r:mi></r:mrow><r:mrow><r:mi>γ</r:mi></r:mrow></r:msubsup><r:mo>/</r:mo><r:msqrt><r:mrow><r:mi>S</r:mi></r:mrow></r:msqrt><r:mo>≃</r:mo><r:mn>0.2</r:mn><r:mi>–</r:mi><r:mn>0.3</r:mn></r:mrow></r:math>. Predictions for the future SPD NICA experiment were discussed. Published by the American Physical Society 2024