7.2 EFT reweighting
7.2.2 Conclusions and outlook
TheHH reweighting method has been tested by modifying only κλ and leaving all other couplings at their SM values. The observed agreement between the reweighted and unweighted samples is not perfect for all bins and some deviations are observed. When modifying a single cou-pling, as is done here forκλ, this method is not ideal and a more simple
Figure 7.3: Comparison between the mhh distribution at generator (truth) level in samples generated with different values of κλ and the SM (κλ = 1) sample reweighted to the same κλ values using the LO EFT reweighting described in [52]. The ratio between the unweighted and the reweighted samples is shown in the bottom pad.
7.2. EFT REWEIGHTING 91
Figure 7.4: Comparison between the |cos θ∗| distribution at generator (truth) level in samples generated with different values ofκλ and the SM (κλ = 1) sample reweighted to the same κλ values using the LO EFT reweighting described in [52]. The ratio between the unweighted and the reweighted samples is shown in the bottom pad.
Figure 7.5: Comparison between the mhh distribution at generator (truth) level in samples generated with different values of κλ and the κλ = 4 sample reweighted to the same κλ values using the LO EFT reweighting described in [52]. The ratio between the unweighted and the reweighted samples is shown in the bottom pad.
7.2. EFT REWEIGHTING 93
Figure 7.6: Comparison between the mhh distribution at generator (truth) level of LO and NLO unweighted SM (κλ = 1). The ratio be-tween the LO and NLO samples is shown in the bottom pad.
reweighting could be performed, by extracting weights from a set of MC simulations that differ only on the κλ coupling, yielding better results.
However it should be noted that the EFT method allows to modify mul-tiple couplings simultaneously, resulting in worse accuracy for a single coupling but giving a more powerful tool. Taking this into account the agreement observed between the reweighted and unweighted samples is considered satisfactory.
The greatest benefit of the EFT reweighting is that multiple couplings can be modified simultaneously. A set of 12 benchmarks with specific coupling values have been proposed [52],[53], where each benchmark is a specific point in the parameter space formed byκλ,κt,c2,cg and c2g. The benchmarks have been chosen such that each represents a possible shape of themhh distribution. Setting limits on this benchmarks allows to exclude certain mhh shape distributions which would be given in the EFT framework. A continuation of the studies presented in this chapter would consist on reweighting the NLO HH samples by varying multiple couplings and setting limits on the benchmarks proposed in [53], as has already been done by CMS [51].
Figure 7.7: Comparison of themhhdistribution at generator (truth) level in samples generated at LO with different κλ values and the NLO SM (κλ = 1) sample reweighted to different κλ values with the NLO EFT reweighting described in [53]. The ratio between the unweighted and reweighted samples is shown in the bottom pad.
7.2. EFT REWEIGHTING 95
Figure 7.8: Comparison of themhhdistribution at generator (truth) level in the SM NLO sample (κλ = 1) reweighted to κλ = 10 and the sample generated at LO (left) or NLO (right) withκλ = 10 samples.
Appendix A
Additional Mistag rate calibration results
In Chapter 5, the negative-tag mistag rate calibration is presented, how-ever only results for the DL1r tagger using P f low jets are shown. This appendix contains the calibration results for the DL1 tagger usingP f low or V Rtrack jets, and the DL1r tagger using V Rtrack jets.
97
Figure A.1: DL1 light jet calibration scale factors and associated uncer-tainties for the different working points usingP f low jets.
99
Figure A.2: DL1r light jet calibration scale factors and associated un-certainties for the different working points usingV Rtrack jets.
Figure A.3: DL1 light jet calibration scale factors and associated uncer-tainties for the different working points usingV Rtrack jets.
Appendix B
Additional distributions in the t¯ tZ CR
Chapter 6 describes the search for new phenomena with top quark pairs in final states with one lepton, jets and missing transverse momentum [42]. In this search, a CR is defined to correct for any mismodelling of the t¯t+Z background which contaminates the SRs. In addition to the distributions for this CR that are already shown in Chapter 6, this appendix contains the distributions, in thet¯tZ CR, of the discriminating variables that are used in the definition of the corresponding SR.
101
Jet multiplicity
0.5 1 1.5
Data / SM
0 1 2 3 4 5 6 7 8
Jet multiplicity 0
5 10 15 20 25 30 35 40
Events Data Total SMZtt Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
[GeV]
miss ll invis
→ T,z E
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
miss ll invis
→ ET,z 0
5 10 15 20 25 30
Events / 25 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
significance miss T H
0.5 1 1.5
Data / SM
−20−15−10−5 0 5 10 15 20 25 30 significance miss HT 0
5 10 15 20 25 30 35
Events / 5
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
[GeV]
reclustered mtop
0.5 1 1.5
Data / SM
0 20 40 60 80 100 120 140 160 180 200 [GeV]
reclustered mtop 0
10 20 30 40 50 60
Events / 20 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
[GeV]
mτT2
0.5 1 1.5
Data / SM
−10−8−6 −4−2 0 2 4 6 8 10 [GeV]
τT2 m 0
20 40 60 80 100
Events / 1 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
[GeV]
miss T E
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
miss ET 0
5 10 15 20 25 30 35
Events / 50 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
) miss T (lep, E φ
∆
0.5 1 1.5
Data / SM
1 1.5 2 2.5 3 3.5 4 4.5 5
miss) (lep, ET φ
∆ 0
10 20 30 40 50 60
Events / 0.4
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
[GeV]
mT
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
mT 0
5 10 15 20 25 30
Events / 50 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
topness
0.5 1 1.5
Data / SM
−20−15−10 −5 0 5 10 15 20 topness 0
2 4 6 8 10 12 14 16
Events Data Total SMZtt Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
) 1 , j miss T φ(E
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.5
1) miss, j (ET φ
∆ 0
5 10 15 20 25
Events / 0.205882
Data Total SM
Z t
t Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
) 2 , j miss T φ(E
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.5
2) miss, j (ET φ
∆ 0
2 4 6 8 10 12 14 16
Events / 0.205882
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
R(b-jet, lepton)
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.54 4.55
R(b-jet, lepton)
∆ 0
5 10 15 20 25
Events / 0.2
Data Total SM
Z t
t Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
Figure B.1: Distributions, in the t¯tZ CR, of discriminating variables used in the definition of the DM SR.
103
Jet multiplicity
0.5 1 1.5
Data / SM
0 1 2 3 4 5 6 7 8
Jet multiplicity 0
5 10 15 20 25 30 35
Events Data Total SMZtt Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
[GeV]
miss ll invis
→ T,z E
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
miss ll invis
→ ET,z 0
2 4 6 8 10 12 14 16 18 20 22 24
Events / 25 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
significance miss T H
0.5 1 1.5
Data / SM
−20−15−10−5 0 5 10 15 20 25 30 significance miss HT 0
5 10 15 20 25 30 35
Events / 5
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
[GeV]
reclustered mtop
0.5 1 1.5
Data / SM
0 20 40 60 80 100 120 140 160 180 200 [GeV]
reclustered mtop 0
5 10 15 20 25 30 35 40
Events / 20 GeV
Data Total SM Z t
t Multiboson
tWZ Others
= 13 TeV, 139.0 fb-1 s
[GeV]
mτT2
0.5 1 1.5
Data / SM
−10−8−6 −4−2 0 2 4 6 8 10 [GeV]
τT2 m 0
10 20 30 40 50 60 70 80 90
Events / 1 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
[GeV]
miss T E
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
miss ET 0
5 10 15 20 25 30
Events / 50 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
[GeV]
miss T perp. E
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
miss perp. ET 0
5 10 15 20 25 30 35 40 45
Events / 50 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
[GeV]
mT
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
mT 0
5 10 15 20 25 30
Events / 50 GeV
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
topness
0.5 1 1.5
Data / SM
−20−15−10 −5 0 5 10 15 20 topness 0
2 4 6 8 10 12 14 16 18
Events Data Total SMZtt Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
) 1 , j miss T φ(E
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.5
1) miss, j (ET φ
∆ 0
2 4 6 8 10 12 14 16 18 20 22
Events / 0.205882
Data Total SM
Z t
t Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
) 2 , j miss T φ(E
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.5
2) miss, j (ET φ
∆ 0
2 4 6 8 10 12 14 16
Events / 0.205882
Data Total SM
Z t
t Multiboson
tWZ t+X
Others = 13 TeV, 139.0 fb-1 s
R(b-jet, lepton)
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.54 4.55
R(b-jet, lepton)
∆ 0
2 4 6 8 10 12 14 16 18 20
Events / 0.2
Data Total SM
Z t
t Multiboson
tWZ t+X
Others
= 13 TeV, 139.0 fb-1 s
Figure B.2: Distributions, in the t¯tZ CR, of discriminating variables used in the definition of the tN_med SR.
Jet multiplicity
0.5 1 1.5
Data / SM
0 1 2 3 4 5 6 7 8
Jet multiplicity 0
10 20 30 40 50 60
Events Data Total SMZtt Multiboson
tWZ Others
= 13 TeV, 139.0 fb-1 s
[GeV]
miss ll invis
→ T,z E
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
miss ll invis
→ ET,z 0
5 10 15 20 25 30 35 40
Events / 25 GeV
Data Total SM
Z t t Multiboson tWZ Others = 13 TeV, 139.0 fb-1
s
significance miss T H
0.5 1 1.5
Data / SM
−20−15−10−5 0 5 10 15 20 25 30 significance miss HT 0
10 20 30 40 50 60 70
Events / 5
Data Total SM
Z t t Multiboson tWZ Others = 13 TeV, 139.0 fb-1
s
[GeV]
reclustered mtop
0.5 1 1.5
Data / SM
0 20 40 60 80 100 120 140 160 180 200 [GeV]
reclustered mtop 0
10 20 30 40 50 60 70 80
Events / 20 GeV
Data Total SM Z t
t Multiboson
tWZ Others
= 13 TeV, 139.0 fb-1 s
[GeV]
mτT2
0.5 1 1.5
Data / SM
−10−8−6 −4−2 0 2 4 6 8 10 [GeV]
τT2 m 0
20 40 60 80 100 120 140 160 180
Events / 1 GeV
Data Total SM
Z t t Multiboson tWZ Others = 13 TeV, 139.0 fb-1
s
[GeV]
miss T E
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
miss ET 0
10 20 30 40 50 60
Events / 50 GeV
Data Total SM
Z t t Multiboson tWZ Others = 13 TeV, 139.0 fb-1
s
[GeV]
miss T perp. E
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
miss perp. ET 0
20 40 60 80 100
Events / 50 GeV
Data Total SM
Z t t Multiboson tWZ Others = 13 TeV, 139.0 fb-1
s
[GeV]
mT
0.5 1 1.5
Data / SM
0 50 100 150 200 250 300 350 400 450 500 [GeV]
mT 0
10 20 30 40 50
Events / 50 GeV
Data Total SM
Z t t Multiboson tWZ Others = 13 TeV, 139.0 fb-1
s
topness
0.5 1 1.5
Data / SM
−20−15−10 −5 0 5 10 15 20 topness 0
5 10 15 20 25 30 35
Events Data Total SMZtt Multiboson
tWZ Others
= 13 TeV, 139.0 fb-1 s
) 1 , j miss T φ(E
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.5
1) miss, j (ET φ
∆ 0
5 10 15 20 25 30 35 40 45
Events / 0.205882
Data Total SM Z t
t Multiboson
tWZ Others
= 13 TeV, 139.0 fb-1 s
) 2 , j miss T φ(E
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.5
2) miss, j (ET φ
∆ 0
5 10 15 20 25
Events / 0.205882
Data Total SM
Z t t Multiboson tWZ Others = 13 TeV, 139.0 fb-1
s
R(b-jet, lepton)
∆
0.5 1 1.5
Data / SM
0 0.5 1 1.5 2 2.5 3 3.54 4.55
R(b-jet, lepton)
∆ 0
5 10 15 20 25 30 35
Events / 0.2
Data Total SM Z t
t Multiboson
tWZ Others
= 13 TeV, 139.0 fb-1 s
Figure B.3: Distributions, in the t¯tZ CR, of discriminating variables used in the definition of the tN_high SR.
Bibliography
[1] D.H. Perkins. Introduction to high energy physics. 1 1982.
[2] I.S. Hughes. Elementary particles. 1985.
[3] F. Halzen and Alan D. Martin. Quarks and leptons: An introductory course in modern particle physics. John Wiley and sons, 1 1984.
[4] C. N. Yang and R. L. Mills. Conservation of isotopic spin and isotopic gauge invariance. Phys. Rev., 96:191–195, Oct 1954.
[5] E. Noether. Invariante Variationsprobleme. Nachr. d. König.
Gesellsch. d. Wiss. zu Göttingen, Math-phys. Klasse, Seite 235-157, 1918.
[6] David J Griffiths. Introduction to elementary particles; 2nd rev.
version. Physics textbook. Wiley, New York, NY, 2008.
[7] I. Van Vulpen. The standard model higgs boson.
"http://web.mst.edu/∼hale/courses/Physics_357_457/Notes/
Lecture.17.Higgs.Mechanism/HiggsLectureNote.pdf", 2013.
[8] John Ellis. Higgs Physics. (2013-49. KCL-PH-TH-2013-49. LCTS-2013-36. CERN-PH-TH-2013-315):117–168. 52 p, Dec 2013. 52 pages, 45 figures, Lectures presented at the ESHEP 2013 School of High-Energy Physics, to appear as part of the pro-ceedings in a CERN Yellow Report.
[9] Harald Fritzsch. Elementary particles: Building blocks of matter.
2005.
[10] The ATLAS Collaboration. Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detec-tor at the LHC. Phys. Lett. B, 716:1–29, 2012.
105
[11] The CMS Collaboration. Observation of a New Boson at a Mass of 125 GeV with the CMS Experiment at the LHC. Phys. Lett. B, 716:30–61, 2012.
[12] Q.R. Ahmad et al. Measurement of the rate ofνe+d→ p+p+e− in-teractions produced by8B solar neutrinos at the Sudbury Neutrino Observatory. Phys. Rev. Lett., 87:071301, 2001.
[13] Y. Fukuda et al. Evidence for oscillation of atmospheric neutrinos.
Phys. Rev. Lett., 81:1562–1567, 1998.
[14] Andrea Wulzer. Behind the Standard Model. In 2015 European School of High-Energy Physics, 1 2019.
[15] M. Tanabashi et al. Review of Particle Physics. Phys. Rev. D, 98(3):030001, 2018.
[16] B. Grzadkowski, M. Iskrzynski, M. Misiak, and J. Rosiek.
Dimension-Six Terms in the Standard Model Lagrangian. JHEP, 10:085, 2010.
[17] T. Affolder et al. Charged Jet Evolution and the Underlying Event inp¯p Collisions at 1.8 TeV. Phys. Rev. D, 65:092002, 2002.
[18] S.D. Ellis, J. Huston, K. Hatakeyama, P. Loch, and M. Tonnesmann.
Jets in hadron-hadron collisions. Prog. Part. Nucl. Phys., 60:484–
551, 2008.
[19] Joao Pequenao. Computer generated image of the whole ATLAS detector. Mar 2008.
[20] Matthias Schott and Monica Dunford. Review of single vector boson production in pp collisions at √
s = 7 TeV. Review of single vector boson production in pp collisions at √
s = 7 TeV. Eur. Phys. J.
C, 74(arXiv:1405.1160):60 p, May 2014. Comments: 60 pages, 64 figures, For Eur. Phys. J. C.
[21] Karolos Potamianos. The upgraded Pixel detector and the commis-sioning of the Inner Detector tracking of the ATLAS experiment for Run-2 at the Large Hadron Collider. Technical Report ATL-PHYS-PROC-2016-104, CERN, Geneva, Aug 2016. 15 pages, EPS-HEP 2015 Proceedings.
[22] Marija Marjanovic. ATLAS Tile calorimeter calibration and mon-itoring systems. IEEE Trans. Nucl. Sci., 66(arXiv:1806.09156.
BIBLIOGRAPHY 107 7):1228–1235. 8 p, Jun 2018. 8 pages, 21 figures, IEEE Real Time 2018 proceedings.
[23] The ATLAS collaboration. The Laser calibration of the Atlas Tile Calorimeter during the LHC run 1. JINST, 11(10):T10005, 2016.
[24] The ATLAS Collaboration. A neural network clustering algorithm for the ATLAS silicon pixel detector. JINST, 9:P09009, 2014.
[25] The ATLAS Collaboration. Electron reconstruction and identifi-cation in the ATLAS experiment using the 2015 and 2016 LHC proton-proton collision data at √
s = 13 TeV. Eur. Phys. J. C, 79(8):639, 2019.
[26] The ATLAS Collaboration. Muon reconstruction performance of the ATLAS detector in proton–proton collision data at √
s =13 TeV. Eur. Phys. J. C, 76(5):292, 2016.
[27] Caterina Doglioni. Measurement of the inclusive jet cross section with the ATLAS detector at the Large Hadron Collider. PhD thesis, University of Oxford, 2011. Presented 28 Oct 2011.
[28] Matteo Cacciari, Gavin P. Salam, and Gregory Soyez. The anti-kt jet clustering algorithm. JHEP, 04:063, 2008.
[29] The ATLAS Collaboration. Jet reconstruction and performance using particle flow with the ATLAS Detector. Eur. Phys. J. C, 77(7):466, 2017.
[30] The ATLAS Collaboration. Performance of b-Jet Identification in the ATLAS Experiment. JINST, 11(04):P04008, 2016.
[31] The ATLAS Collaboration. Optimisation and performance stud-ies of the ATLAS b-tagging algorithms for the 2017-18 LHC run.
Technical Report ATL-PHYS-PUB-2017-013, CERN, Geneva, Jul 2017.
[32] The ATLAS Collaboration. Identification of Jets Containing b-Hadrons with Recurrent Neural Networks at the ATLAS Ex-periment. Technical Report ATL-PHYS-PUB-2017-003, CERN, Geneva, Mar 2017.
[33] The ATLAS Collaboration. Secondary vertex finding for jet flavour identification with the ATLAS detector. Technical Report ATL-PHYS-PUB-2017-011, CERN, Geneva, Jun 2017.
[34] The ATLAS Collaboration. Topologicalb-hadron decay reconstruc-tion and identificareconstruc-tion of b-jets with the JetFitter package in the ATLAS experiment at the LHC. Technical Report ATL-PHYS-PUB-2018-025, CERN, Geneva, Oct 2018.
[35] A. Hoecker et al. Tmva - toolkit for multivariate data analysis.
arXiv/0703039, 2007.
[36] Rami Al-Rfou et al. Theano: A python framework for fast compu-tation of mathematical expressions. CoRR, abs/1605.02688, 2016.
[37] The ATLAS Collaboration. Calibration of light-flavourb-jet mistag-ging rates using ATLAS proton-proton collision data at √
s = 13 TeV. Technical Report ATLAS-CONF-2018-006, CERN, Geneva, Apr 2018.
[38] T. Gleisberg, S. Höche, F. Krauss, M. Schönherr, S. Schumann, et al. Event generation with SHERPA 1.1. JHEP, 02:007, 2009.
[39] J. Alwall, R. Frederix, S. Frixione, V. Hirschi, F. Maltoni, et al.
The automated computation of tree-level and next-to-leading or-der differential cross sections, and their matching to parton shower simulations. JHEP, 07:079, 2014.
[40] Stefano Frixione, Paolo Nason, and Carlo Oleari. Matching NLO QCD computations with parton shower simulations: the POWHEG method. JHEP, 11:070, 2007.
[41] ATLAS Collaboration. Measurement ofb-tagging efficiency of c-jets in t¯t events using a likelihood approach with the ATLAS detector.
ATLAS-CONF-2018-001, 2018.
[42] The ATLAS Collaboration. Search for new phenomena with top quark pairs in final states with one lepton, jets, and missing trans-verse momentum in pp collisions at√
s = 13 TeV with the ATLAS detector. 2 2020.
[43] The ATLAS Collaboration. Search for top-squark pair production in final states with one lepton, jets, and missing transverse momentum using 36 fbfl1 of √
s = 13 TeV pp collision data with the ATLAS detector. JHEP, 06:108, 2018.
[44] The ATLAS Collaboration. Performance of the missing transverse momentum triggers for the ATLAS detector during Run-2 data tak-ing. JHEP, 08:080, 2020.