lhc itools
play

LHC-iTools Methods and tools for the interpretation of the LHC - PowerPoint PPT Presentation

Dec 06, 2022 •346 likes •537 views

LHC-iTools Methods and tools for the interpretation of the LHC results Sabine Kraml - conseil scientifique - 23 Jan 2018 Motivation The search for new phenomena beyond the SM (BSM) is one of the top priorities of the LHC program. To this

  1. LHC-iTools Methods and tools for the interpretation of the LHC results Sabine Kraml - conseil scientifique - 23 Jan 2018

  2. Motivation • The search for new phenomena beyond the SM (BSM) is one of the top priorities of the LHC program. • To this end, the LHC collaborations are pursuing - precision measurements of “known” processes (jets, EW boson, top quark, Higgs, etc. prod.) \ - searches for new physics in a vast variety of channels. • Results are typically interpreted by the experiments in terms of the SM, popular minimal BSM scenarios, simplified models, EFT fits, … often on an analysis-by- analysis basis. • For a full understanding of the implications for physics at the TeV scale physics we need, however, to be able to confront all kinds of theoretical models against the LHC results. • Close theory-experiment interaction • Sophisticated public tools for a comprehensive, global view of what the data tell us about TeV scale physics.

  3. Why build tools for (re)interpretation? 1. Avoid the streetlight e ff ect 2. Ensure long-term impact of results, use in global analyses, etc. new theories nobody has though of yet not sexy not mainstream non-minimal models soft stu ff vanilla new physics ‘weird’ signatures We want to know what all(!) the LHC and other data tell us about the TeV scale and beyond

  4. Activities at the LPSC Reinterpretation of Recasting based on MC Simplified Model results event simulation Interpretation of Higgs measurements

  5. Higgs constraints on new physics: Lilith and beyond • From end of 2011 onwards, we pursued detailed studies of the implications of the 125 GeV Higgs boson for new physics ‣ 5 topCite100+, 4 topCite50+, 1 PRL ‣ “editor’s suggestion” and “pick of the month” in PRD • The computer code developed for this purpose was 2HDM Type I Run1+Run2 turned into a public program ( Lilith ) by two of our students: ‣ J. Bernon, B. Dumont, Eur.Phys.J. C75 (2015) no.9 ‣ Springer Thesis Award for B. Dumont 2HDM Type II • Lilith is a Python library which assess the compatibility Run1+Run2 of a non-standard Higgs sector with all available signal strength measurements of the observed state at 125 GeV. • Easily extensible and very fast, which is important for large scans. The results of Lilith can be used to constrain a wide class of new physics scenarios.

  6. Higgs constraints on new physics: Lilith and beyond • If the kinematic distribution of the 125 GeV Higgs signal depends on model parameters, simple scaling of production cross sections and decay branching ratios (relative to the SM) is invalid ➡ must account for the change in the signal selection e ffi ciency. • This can arise from new tensor structures or the presence of new Higgs production modes , e.g., from decays of heavier new states. ➡ particle-level di ff erential measurements • ATLAS and CMS are providing total and di ff erential fiducial cross section measurements for several Higgs decay modes, as well as ` simplified template cross sections’ for specific production modes. Future: We want to develop the relevant machinery for making use of these data.

  7. Using simplified model results: SModelS • It has become standard that ATLAS and CMS present the results of their BSM searches in terms of “simplified model” constraints. • Simplified models (SMS) reduce full models with a plethora of particles and parameters to subsets with just 2-3 new states and a simple decay pattern. • Concept used by SUSY, Exotics, DM searches ~ ~ ~ ∼ pp → t t , t → t χ 0 Moriond 2017 1 900 [GeV] -1 CMS Preliminary 35.9 fb (13 TeV) 800 miss Expected SUS-16-033, 0-lep (H ) T 0 1 Observed ∼ χ SUS-16-036, 0-lep (M ) • Very convenient for optimising analyses that m 700 T2 SUS-16-049, 0-lep stop ~ ~ ~ SUS-16-051, 1-lep stop ∼ 600 pp q q , q q 0 → → χ Moriond 2017 SUS-17-001, 2-lep stop 1 1200 [GeV] Comb. 0-, 1- and 2-lep stop 500 -1 CMS Preliminary 35.9 fb (13 TeV) ~ ~ ~ Expected ∼ 400 pp → b b , b → b χ 0 1000 miss Moriond 2017 look for a particular final state, as well as for 0 1 SUS-16-033, 0-lep (H ) Observed ∼ χ T 1 900 m [GeV] SUS-16-036, 0-lep (M ) -1 CMS Preliminary 35.9 fb (13 TeV) 300 T2 800 800 Expected SUS-16-032, 0-lep sbottom 200 ∼ 0 1 Observed ~ ~ ~ ∼ χ χ miss pp → g g , g → t t 0 m SUS-16-033, 0-lep (H ) 700 comparing the reach of di ff erent strategies. Moriond 2017 T 1 ~ ~ ~ ~ ~ SUS-16-036, 0-lep (M ) ~ [GeV] q + q ( u , d , s , c ) T2 100 2000 600 L R m ∼ 0 CMS Preliminary 35.9 fb -1 (13 TeV) 600 + χ 1 m t = m ~ 1800 0 t miss SUS-16-033, 0-lep (H ) 200 400 600 800 1000 1200 T Expected 0 1 500 ∼ χ SUS-16-036, 0-lep (M 400 ) m Observed 1600 T2 m [GeV] SUS-16-037, 1-lep (M ~ ) J t 400 SUS-16-042, 1-lep ( ∆ φ ) ~ 1400 • Understanding how SMS results constrain a one light q SUS-16-035, ≥ 2-lep (SS) 200 SUS-16-041, ≥ 3-lep 300 1200 200 1000 0 400 600 800 1000 1200 1400 1600 1800 800 100 m [GeV] ~ q realistic model with a multitude of parameters, 600 0 400 500 600 700 800 900 1000 1100 1200 1300 400 m [GeV] ~ b 200 relevant production channels and decay modes 0 800 1000 1200 1400 1600 1800 2000 2200 m [GeV] ~ g is, however, a non-trivial task. • Automated tool:

  8. Using simplified model results: SModelS collaboration with Santo Andre (A. Lessa) and Vienna (W. Waltenberger) Working principle of SModelS

  9. Using simplified model results: SModelS Postdoc: S. Kulkarni 2012-2014, • Since the first public release in 2014 (v1.0), the code now at HEPHY Vienna. base has undergone significant structural changes. 1 Fraction of excluded points Excluded by EM • Version 1.1 published in 2017 comes with many new 0.9 Excluded by UL 0.8 features; most important: use of e ffi ciency maps . 0.7 • Extensive database : 186 results from 21 ATLAS and 0.6 0.5 23 CMS SUSY searches, covering 37 topologies. 0.4 0.3 • Update to 35/fb results from CMS in progress 0.2 0.1 (ATLAS did not yet provide 13 TeV SMS results which can be used) 0 500 1000 1500 2000 2500 3000 3500 4000 Gluino mass [GeV] Fraction of Bino LSP ATLAS excluded points excluded by SModelS Fraction of Bino LSP ATLAS excluded points excluded by SModelS 1000 1 [GeV] 1 • Variety of phenomenological studies, 1 1 900 0.9 3 3 3 1 1 35 8 6 1 3 1 800 0.8 0 1 e.g. constraints on sneutrino LSP χ ~ 62 58 14 9 9 8 8 3 1 m 289 60 23 26 25 22 18 13 5 1 700 0.7 180 319 58 55 65 48 64 41 33 21 11 12 4 1 • Extensive study of the coverage of the 691 119 62 89 71 71 63 62 59 41 29 15 12 8 600 0.6 312 618 111 80 106 97 102 83 97 90 63 57 38 29 16 944 131 129 114 123 149 118 138 116 122 103 103 73 48 29 pMSSM by simplified model results 500 0.5 368 706 139 131 153 131 174 143 136 141 139 138 119 88 62 47 1133 139 149 143 139 153 167 135 148 144 129 101 85 78 74 49 400 0.4 • Identified important missing topologies 518 773 147 140 133 181 162 152 154 128 94 92 109 84 64 49 63 1152 131 123 140 149 157 140 133 106 109 109 88 90 90 63 57 84 300 0.3 393 607 137 137 112 124 148 115 109 107 127 105 96 100 85 85 85 63 88 117 100 111 102 105 112 106 107 128 132 103 134 125 108 107 82 85 • Many talks, e.g., CHEP, EPS-HEP 200 0.2 20 71 81 70 85 98 94 105 114 105 114 104 87 64 86 98 82 82 13 38 48 53 43 57 48 60 53 61 55 53 46 53 65 36 37 47 100 0.1 14 67 75 55 74 82 83 95 77 104 104 71 78 67 110 107 111 102 12 90 86 81 90 89 103 107 111 97 111 95 114 111 101 82 124 97 0 0 Thesis of U. Laa, 2017 0 200 400 600 800 1000 1200 1400 1600 1800 2000 m [GeV] ~ g 9

  10. Using simplified model results: SModelS Future plans: • Produce new e ffi ciency maps for simplified models not considered by ATLAS and CMS to improve coverage of complex models • Test constraints on new models like SUSY with Dirac gauginos • Include lifetime information to be able to treat constraints from searches for long-lived particles (needs restructuring of database) • Extend the model input from SLHA(-like) files to the Lagrangian level, in order to be able to link to, e.g., MadGraph implementations of new models. • Finally, to go beyond the assumption of a Z2 symmetry we will completely revise the SModelS internal language used for the decomposition and the matching with the results in the database. The data description in the results database itself also has to be adapted. This will be SModelSv2.0. - New PhD student, H. Reyes Gonzalez, started in Oct. 2017 - PRC project for collaboration with A. Lessa in Brasil (awaiting renewal for 2018) - Bilateral ANR-FWF project with HEPHY Vienna submitted in Jan 2018 NB: both Lilith and SModelS were interfaced to micrOMEGAS ( Comput. Phys. Comm. 222, 2018.) 10

Recommend

More recommend