CMS-PAS-SMP-22-009

CMS-PAS-SMP-22-009
Measurement of the $ Z(\nu\bar{\nu})+\gamma $ production cross section and search for anomalous neutral triple gauge couplings in pp collisions at 13 TeV
CMS Collaboration
12 April 2024

Abstract: The measurement of the production cross section of a Z boson and a photon in the final state with one photon and large missing transverse momentum, and a search for the presence of neutral anomalous triple gauge couplings are presented. The results are based on data collected by the CMS experiment in proton-proton collisions at $ \sqrt{s}= $ 13 TeV during the 2016, 2017, and 2018 LHC running periods, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. The measured cross section is compatible with the theoretical predictions at the next-to-next-to-leading order in QCD. The study of the photon transverse momentum spectrum yields the most stringent limits on the anomalous triple gauge couplings provided by the CMS experiment to date.
Links: CDS record (PDF) ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: The Feynman diagram for the ZV$ \gamma $ vertex, where V$ =\gamma^{}/\mathrm{Z}^{} $, in the presence of aNTGC.
png pdf	Figure 2: The Feynman diagram for the SM Z$\gamma$ production in the t-channel (left), and the additional diagram for the beyond SM s-channel (right) Z$\gamma$ production due to the presence of aNTGCs.
png pdf	Figure 2-a: The Feynman diagram for the SM Z$\gamma$ production in the t-channel (left), and the additional diagram for the beyond SM s-channel (right) Z$\gamma$ production due to the presence of aNTGCs.
png pdf	Figure 2-b: The Feynman diagram for the SM Z$\gamma$ production in the t-channel (left), and the additional diagram for the beyond SM s-channel (right) Z$\gamma$ production due to the presence of aNTGCs.
png pdf	Figure 3: The photon $ p_{\mathrm{T}} $ spectrum for various values of aNTGC couplings and the SM predictions. These samples were produced using MadGraph-5_aMC@NLO [34].
png pdf	Figure 4: Measured and predicted differential cross sections as a function of $ p_{\mathrm{T}}^{\gamma} $ for the combined fiducial phase space.
png pdf	Figure 5: Confidence contours of the aNTGC parameters $ h_3^\gamma, h_4^\gamma $ (left) and $ h_3^Z, h_4^Z $ (right).
png	Figure 5-a: Confidence contours of the aNTGC parameters $ h_3^\gamma, h_4^\gamma $ (left) and $ h_3^Z, h_4^Z $ (right).
png	Figure 5-b: Confidence contours of the aNTGC parameters $ h_3^\gamma, h_4^\gamma $ (left) and $ h_3^Z, h_4^Z $ (right).
png pdf	Figure 6: Comparison of the predicted distribution of $ p_{\mathrm{T}}^{\gamma} $ under the SM-only hypothesis in the barrel (left), and in the endcaps phase space (right) with the predictions at the upper boundaries of the observed 1D confidence intervals of the coupling parameters. The bottom panels compare the SM (shown in red) and the aNTGC predictions, with the observed $ p_{\mathrm{T}}^{\gamma} $ distribution (shown in black).
png	Figure 6-a: Comparison of the predicted distribution of $ p_{\mathrm{T}}^{\gamma} $ under the SM-only hypothesis in the barrel (left), and in the endcaps phase space (right) with the predictions at the upper boundaries of the observed 1D confidence intervals of the coupling parameters. The bottom panels compare the SM (shown in red) and the aNTGC predictions, with the observed $ p_{\mathrm{T}}^{\gamma} $ distribution (shown in black).
png	Figure 6-b: Comparison of the predicted distribution of $ p_{\mathrm{T}}^{\gamma} $ under the SM-only hypothesis in the barrel (left), and in the endcaps phase space (right) with the predictions at the upper boundaries of the observed 1D confidence intervals of the coupling parameters. The bottom panels compare the SM (shown in red) and the aNTGC predictions, with the observed $ p_{\mathrm{T}}^{\gamma} $ distribution (shown in black).

Tables
png pdf	Table 1: Systematic uncertainties and their impact on the prediction for the signal. A checkmark indicates full correlation between years.
png pdf	Table 2: Post-fit event yields in the photon-$ p_{\mathrm{T}} $ spectrum for the combined phase space.
png pdf	Table 3: Measured and predicted cross sections (in femtobarns) evaluated in the barrel, the endcaps, and the combined fiducial phase spaces. The predicted cross sections are calculated at NLO and NNLO in QCD.
png pdf	Table 4: Measured and predicted cross sections (in fb) in bins of $ p_{\mathrm{T}}^{\gamma} $.
png pdf	Table 5: Expected and observed confidence intervals (95% confidence level) of the parameters of anomalous couplings.

Summary

We have measured the inclusive and differential cross sections of $ Z(\rightarrow\nu\bar{\nu})+\gamma $ at $ \sqrt{s} = $ 13 TeV in proton-proton collisions using 138 fb$ ^{-1} $ of data collected by the CMS detector. The inclusive cross section of $ Z(\rightarrow\nu\bar{\nu})+\gamma $ is measured to be 26.1 $ ^{+1.6}_{-1.5} $ fb, in agreement with the standard model predictions. The $ p_{\mathrm{T}} $ differential cross section has been measured for the photons and compared with the standard model predictions computed at next-to-leading and next-to-next-to-leading orders in perturbative quantum chromodynamics. With this data we have also placed constraints on the presence of anomalous couplings that affect the ZZ$\gamma $ vertex by using the $ p_{\mathrm{T}} $ spectrum of the photons as the sensitive variable. The observed 95% confidence level intervals for $ h_3^{\gamma} $ and $ h_4^{\gamma} $ are determined to be ($-$3.4, 3.5) $\times$ 10$^{-4} $ and ($-$6.8, 6.8) $\times$ 10$^{-7} $; and for $ h_3^{Z} $ and $ h_4^{Z} $ ($-$2.2, 2.2) $\times$ 10$^{-4} $ and ($-$4.1, 4.2) $ \times$ 10$^{-7} $ respectively. The sensitivities to CP-conserving and CP-violating couplings are comparable in the $ p_{\mathrm{T}} $ regime that we probe.

References
1	K. Hagiwara, R. Peccei, D. Zeppenfeld, and K. Hikasa	Probing the weak boson sector in $ e^+ e^- \rightarrow W^+ W^- $	NPB 282 (1987) 253
2	U. Baur and E. L. Berger	Probing the weak-boson sector in $ Z\gamma $ production at hadron colliders	PRD 47 (1993) 4889
3	U. Baur, T. Han, and J. Ohnemus	QCD corrections and anomalous couplings in $ Z\gamma $ production at hadron colliders	PRD 57 (1998) 2823
4	G. J. Gounaris, J. Layssac, and F. M. Renard	Signatures of the anomalous $ Z\gamma $ and $ \mathrm{ZZ} $ production at lepton and hadron colliders	PRD 61 (2000) 073013
5	B. Bellazzini and F. Riva	New phenomenological and theoretical perspective on anomalous $ ZZ $ and $ Z\gamma $ processes	PRD 98 (2018) 095021
6	J. Ellis, H.-J. He, and R.-Q. Xiao	Probing neutral triple gauge couplings with $Z^{*}\gamma (\nu\nu\gamma)$ production at hadron colliders	PRD 108 (2023) L111704	2308.16887
7	M. Grazzini, S. Kallweit, and D. Rathlev	W$ \gamma $ and Z$ \gamma $ production at the LHC in NNLO QCD	JHEP 2015 (2015) 85
8	J. M. Campbell, T. Neumann, and C. Williams	Z$ \gamma $ production at NNLO including anomalous couplings	JHEP 2017 (2017) 150
9	A. Denner, S. Dittmaier, M. Hecht, and C. Pasold	NLO QCD and electroweak corrections to Z + $ \gamma $ production with leptonic Z-boson decays	JHEP 2016 (2016) 57
10	D0 Collaboration	Study of $ Z\gamma $ Events and Limits on Anomalous $ ZZ\gamma $ and $ Z\gamma\gamma $ Couplings in $ p\bar{p} $ Collisions at $ \sqrt{s}= $ 1.96 TeV	PRL 95 (2005) 051802
11	CDF Collaboration	Measurement of $ Z\gamma $ production in $ p\bar{p} $ collisions at $ \sqrt{s}= $ 1.96 TeV	PRD 82 (2010) 031103
12	CDF Collaboration	Limits on Anomalous Trilinear Gauge Couplings in $ Z\gamma $ Events from $ p\overline{p} $ Collisions at $ \sqrt{s}=$ 1.96 TeV	PRL 107 (2011) 051802
13	CMS Collaboration	Measurement of the $ Z\gamma $ production cross section in $ pp $ collisions at $ \sqrt{s}= $ 8 TeV and search for anomalous triple gauge boson couplings	JHEP 2015 (2015) 164
14	CMS Collaboration	Measurement of the $ Z\gamma \rightarrow \nu\bar{\nu}\gamma $ production cross section in $ pp $ collisions at $ \sqrt{s}= $ 8 TeV and limits on anomalous $ ZZ\gamma $ and $ Z\gamma\gamma $ trilinear gauge boson couplings	PLB 760 (2016) 448
15	ATLAS Collaboration	Measurements of $ Z\gamma $ and $ Z\gamma\gamma $ production in $ pp $ collisions at $ \sqrt{s}= $ 8 TeV with the ATLAS detector	PRD 93 (2016) 112002
16	ATLAS Collaboration	Measurement of the $ Z\gamma \rightarrow \nu\bar{\nu}\gamma $ production cross section in $ pp $ collisions at $ \sqrt{s}= $ 13 TeV with the ATLAS detector and limits on anomalous triple gauge-boson couplings	JHEP 2018 (2018) 10
17	D0 Collaboration	$ Z\gamma $ production and limits on anomalous $ ZZ\gamma $ and $ Z\gamma\gamma $ couplings in $ p\bar{p} $ collisions at $ \sqrt{s}= $ 1.96 TeV	PLB 653 (2007) 378
18	The ATLAS collaboration	Measurement of W$ \gamma $ and Z$ \gamma $ production in proton-proton collisions at $ \sqrt{s}= $ 7 TeV with the ATLAS detector	JHEP 2011 (2011) 72
19	CMS Collaboration	The CMS experiment at the CERN LHC	JINST 3 (2008) S08004
20	CMS Collaboration	Performance of the CMS Level-1 trigger in proton-proton collisions at $ \sqrt{s} = $ 13TeV	JINST 15 (2020) P10017	CMS-TRG-17-001 2006.10165
21	CMS Collaboration	The CMS trigger system	JINST 12 (2017) P01020	CMS-TRG-12-001 1609.02366
22	CMS Collaboration	Particle-flow reconstruction and global event description with the CMS detector	JINST 12 (2017) P10003	CMS-PRF-14-001 1706.04965
23	CMS Collaboration	Technical proposal for the Phase-II upgrade of the Compact Muon Solenoid	CMS Technical Proposal CERN-LHCC-2015-010, CMS-TDR-15-02, 2015 CDS
24	M. Cacciari, G. P. Salam, and G. Soyez	The anti-$ k_{\mathrm{T}} $ jet clustering algorithm	JHEP 04 (2008) 063	0802.1189
25	M. Cacciari, G. P. Salam, and G. Soyez	FastJet user manual	EPJC 72 (2012) 1896	1111.6097
26	CMS Collaboration	Pileup mitigation at CMS in 13 TeV data	JINST 15 (2020) P09018	CMS-JME-18-001 2003.00503
27	CMS Collaboration	Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV	JINST 12 (2017) P02014	CMS-JME-13-004 1607.03663
28	CMS Collaboration	Performance of missing transverse momentum reconstruction in proton-proton collisions at $ \sqrt{s} = $ 13 TeV using the CMS detector	JINST 14 (2019) P07004	CMS-JME-17-001 1903.06078
29	CMS Collaboration	Measurements of inclusive W and Z cross sections in pp collisions at $ \sqrt{s}= $ 7 TeV	JHEP 01 (2011) 080	CMS-EWK-10-002 1012.2466
30	A. Bodek et al.	Extracting muon momentum scale corrections for hadron collider experiments	EPJC 72 (2012) 2194	1208.3710
31	CMS Collaboration	Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at $ \sqrt{s}= $ 13 TeV	JINST 13 (2018) P06015	CMS-MUO-16-001 1804.04528
32	D. A. Petyt, for the CMS collaboration	Mitigation of Anomalous APD signals in the CMS Electromagnetic Calorimeter	Journal of Physics Conference Series 404 (2012) 012043
33	A. P. Singh, P. C. Bhat, N. V. Mokhov, and S. Beri	Beam-induced radiation in the compact muon solenoid tracker at the large hadron collider	Pramana 74 (2010) 719
34	J. Alwall et al.	The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations	JHEP 07 (2014) 079	1405.0301
35	CMS Collaboration	Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements	EPJC 80 (2020) 4	CMS-GEN-17-001 1903.12179
36	T. Söstrand et al.	\textitAn introduction to PYTHIA 8.2	Comput. Phys. Commun. 191 (2015) 159	1410.3012
37	GEANT4 Collaboration	GEANT 4---a simulation toolkit	NIM A 506 (2003) 250
38	A. Denner, S. Dittmaier, M. Hecht, and C. Pasold	NLO QCD and electroweak corrections to W + $ \gamma $ production with leptonic W-boson decays	JHEP 2015 (2015) 18
39	NNPDF Collaboration	Illuminating the photon content of the proton within a global PDF analysis	SciPost Phys. 5 (2018) 008	1712.07053
40	CMS collaboration	Search for new physics in final states with a single photon and missing transverse momentum in proton-proton collisions at $ \sqrt{s}= $ 13 TeV	JHEP 2019 (2019) 74
41	CMS Collaboration	Precision luminosity measurement in proton--proton collisions at $ \sqrt{s}= $ 13 TeV in 2015 and 2016 at CMS	EPJC 81 (2021) 800
42	CMS Collaboration	CMS luminosity measurement for the 2017 data-taking period at $ \sqrt{s}= $ 13 TeV	CMS Physics Analysis Summary, 2018 CMS-PAS-LUM-17-004	CMS-PAS-LUM-17-004
43	CMS Collaboration	CMS luminosity measurement for the 2018 data-taking period at $ \sqrt{s}= $ 13 TeV	CMS Physics Analysis Summary, 2019 CMS-PAS-LUM-18-002	CMS-PAS-LUM-18-002
44	CMS Collaboration	Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC	JINST 16 (2021) P05014	CMS-EGM-17-001 2012.06888
45	J. M. Lindert et al.	Precise predictions for $ V+ $jets dark matter backgrounds	EPJC 77 (2017) 829
46	J. Butterworth et al.	PDF4LHC recommendations for LHC Run II	Journal of Physics G:, 2016 Nuclear and Particle Physics 43 (2016) 023001
47	A. Gaponenko	A practical way to regularize unfolding of sharply varying spectra with low data statistics	Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, 2020 Detectors and Associated Equipment 960 (2020) 163612
48	M. Grazzini, S. Kallweit, and M. Wiesemann	Fully differential NNLO computations with matrix	EPJC 78 (2018) 537
49	B. Pollack, S. Bhattacharya, and M. Schmitt	Bayesian Block Histogramming for High Energy Physics		1708.00810