Zγ production at NNLO including anomalous couplings
In this paper we present a nexttonexttoleading order (NNLO) QCD calculation of the processes $$pp\rightarrow l^+l^\gamma$$ and $$pp\rightarrow \nu\bar\nu\gamma$$ that we have implemented in MCFM. Our calculation includes QCD corrections at NNLO both for the Standard Model (SM) and additionally in the presence of $$Z\gamma\gamma$$ and $$ZZ\gamma$$ anomalous couplings. We compare our implementation, obtained using the jettiness slicing approach, with a previous SM calculation and find broad agreement. Focusing on the sensitivity of our results to the slicing parameter, we show that using our setup we are able to compute NNLO cross sections with numerical uncertainties of about $$0.1\%$$, which is small compared to residual scale uncertainties of a few percent. We study potential improvements using two different jettiness definitions and the inclusion of power corrections. At $$\sqrt{s}=13$$ TeV we present phenomenological results and consider $$Z\gamma$$ as a background to $$H\to Z\gamma$$ production. Here, we find that, with typical cuts, the inclusion of NNLO corrections represents a small effect and loosens the extraction of limits on anomalous couplings by about $$10\%$$.
 Authors:

^{[1]}
;
^{[2]}
;
^{[2]}
 Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
 Univ. at Buffalo, The State Univ. of New York, Buffalo, NY (United States)
 Publication Date:
 Report Number(s):
 arXiv:1708.02925; FERMILABPUB17303T
Journal ID: ISSN 10298479; 1615212; TRN: US1800108
 Grant/Contract Number:
 AC0207CH11359
 Type:
 Accepted Manuscript
 Journal Name:
 Journal of High Energy Physics (Online)
 Additional Journal Information:
 Journal Name: Journal of High Energy Physics (Online); Journal Volume: 2017; Journal Issue: 11; Journal ID: ISSN 10298479
 Publisher:
 Springer Berlin
 Research Org:
 Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
 Sponsoring Org:
 USDOE Office of Science (SC), High Energy Physics (HEP) (SC25)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; QCD Phenomenology
 OSTI Identifier:
 1410428
Campbell, John M., Neumann, Tobias, and Williams, Ciaran. Zγ production at NNLO including anomalous couplings. United States: N. p.,
Web. doi:10.1007/JHEP11(2017)150.
Campbell, John M., Neumann, Tobias, & Williams, Ciaran. Zγ production at NNLO including anomalous couplings. United States. doi:10.1007/JHEP11(2017)150.
Campbell, John M., Neumann, Tobias, and Williams, Ciaran. 2017.
"Zγ production at NNLO including anomalous couplings". United States.
doi:10.1007/JHEP11(2017)150. https://www.osti.gov/servlets/purl/1410428.
@article{osti_1410428,
title = {Zγ production at NNLO including anomalous couplings},
author = {Campbell, John M. and Neumann, Tobias and Williams, Ciaran},
abstractNote = {In this paper we present a nexttonexttoleading order (NNLO) QCD calculation of the processes $pp\rightarrow l^+l^\gamma$ and $pp\rightarrow \nu\bar\nu\gamma$ that we have implemented in MCFM. Our calculation includes QCD corrections at NNLO both for the Standard Model (SM) and additionally in the presence of $Z\gamma\gamma$ and $ZZ\gamma$ anomalous couplings. We compare our implementation, obtained using the jettiness slicing approach, with a previous SM calculation and find broad agreement. Focusing on the sensitivity of our results to the slicing parameter, we show that using our setup we are able to compute NNLO cross sections with numerical uncertainties of about $0.1\%$, which is small compared to residual scale uncertainties of a few percent. We study potential improvements using two different jettiness definitions and the inclusion of power corrections. At $\sqrt{s}=13$ TeV we present phenomenological results and consider $Z\gamma$ as a background to $H\to Z\gamma$ production. Here, we find that, with typical cuts, the inclusion of NNLO corrections represents a small effect and loosens the extraction of limits on anomalous couplings by about $10\%$.},
doi = {10.1007/JHEP11(2017)150},
journal = {Journal of High Energy Physics (Online)},
number = 11,
volume = 2017,
place = {United States},
year = {2017},
month = {11}
}