CMS Research Report. Vivek Sharma University of California, San Diego. DOE Site Visit, August

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1 CMS Research Report Vivek Sharma University of California, San Diego DOE Site Visit, August

2 Sharma Group on CMS: Executive Summary (I) Postdocs: Adish Vartak, Raffaele Gerosa Major research focus on Higgs Physics, Dark Matter and CMS Silicon Tracker In the past: Higgs discovery and characterization CMS tracking software, Tracker DAQ At present: Dark Matter searches at s = 13 TeV Rare Higgs decays : Hà Invisible Tracker Operations & DAQ 2

3 Leadership roles in CMS: Executive Summary (II) VS: Deputy Publication Board chair ( ) VS: Co-editor CRAFT: Cosmic Run at Four Tesla 22 papers on performance and calibration of CMS sub-detectors published in JINST ( ); crucial to CMS preparation for data Boris Mangano: Tracking coordinator ( ) VS: Higgs coordinator ( ) VS: Founding coordinator, LHC Higgs combination group VS appointed to CMS Higgs Editorial board: 2012-present Higgs EB reviews and finalizes all CMS publications on Higgs physics publications so far Giovanni Petrucciani; Higgs Combination coordinator ( ) Adish Vartak: Contact for Run 2 High Priority Analysis on Search for Monojets with s = 13 TeV data Adish Vartak: MET+X Exotica subgroup Coordinator ( Sept 16) VS served on > 40 Analysis Review Committees, chaired 21 of these. 3

4 Very active and visible in CMS: Talks (selected) 2015-present 4

5 Tracker & Tracking Activities Major contributions to CMS Tracking algorithm & Validation ( ) In 2012 responded to an SOS from USCMS Tracker community to get involved in Si-Tracker Operations which was dangerously low on manpower at P5. Both postdocs involved in : Tracker commissioning configure, calibrate and sync hardware components Tracker Online operations Strip Tracker DAQ expert duties See Raffaele Gerosa talk about Tracker activities 5

6 Physics: Higgs Boson and Dark Matter Run 1 Physics: Search for the Higgs boson HàWWà 2l 2ν ( ) H à ZZà 2l 2ν ( ) H à ZZà 4l (2012 present) Developed procedures to combine results of Higgs results Run 2 Physics: Early running at s = 13 TeV : Search for Dark Matter Higgs decay to invisible Later running at s = 13 TeV: Higgs properties with H à ZZà 4l Rare and exotic Higgs decays; VBF and tth channels 6

7 HàWWà 2l 2ν & HàZZà 2l 2ν ( 7 TeV data) H à WW à (l υ) (lυ) µ e p T ## 38#GeV# H àzz à 2l 2υ p T ## 138#GeV# Z#mass## 92#GeV# ME T ΜET## 228#GeV# Higgs#transverse#mass## 416#GeV# H àww à2l 2ν Limit: 270 < M H < 440 GeV Expected Exclusion at 95% CL : 127 < M H < 270 GeV Observed Exclusion at 95% CL: 129 < M H < 270 GeV 7

8 Combination Of CMS Results On 2011 Data Remaining corridor of uncertainty è Switch to Discovery mode 8

9 We switched to H à ZZ à 4l A High mass resolution discovery mode Most information per event about the nature of Higgs 9

10 PRD doi: /physrevd H à ZZ à 4l : Run 1 dataset σ/σ SM at GeV = p-value: Expected: 6.7σ Observed: 6.8σ 10

11 Higgs Boson Mass and Width from H à ZZ à 4l Scan of the negative log likelihood 2ΔlnL Vs SM Higgs boson mass m H, for each of the three channels separately and their combination Scan of the average expected and observed negative log likelihood 2ΔlnL Vs the tested SM Higgs boson width Γ H Γ H < % CL (Natural width of SM Higgs boson at M H = 126 GeV 4 MeV) 11

12 Higgs Boson Mass and Width from H à ZZ & Hà γγ Scan of the negative log likelihood 2ΔlnL Vs SM Higgs boson mass m H, for each channel separately and their combination Scan of the average expected and observed negative log likelihood 2ΔlnL Vs the tested SM Higgs boson width Γ H 52.CE 12.CD M : = = (stat) (syst) Historic first measurement has precision of 0.24%!! Γ H < % CL Model independent, limited by exptal. resolution 12

13 Higgs Combination: CMS and LHC 13 Actually there are five channels that contribute most at M H =125 GeV + some interpretations of upper limits on rare modes

14 LHC Higgs Combination Group (LHC-HCG) Commissioned by ATLAS & CMS spokesperson in Dec 2010, LHC-HCG was formed with the aim of : Agreeing on the statistical procedure, physics input that the two experiments will use in their publications preparing for an eventual combination of ATLAS and CMS SM Higgs discovery or search results Develop the technical framework and exercise it individually and together using (a) mock data (b) real data (LP11 results/limits) Bill Murray (ATLAS) & Vivek Sharma (CMS) were founding Coordinators of LHC-HCG Strong backing from Fabiola Gianotti, Guido Tonelli and Rolf Hauer on when and how to combine (or not; EPS 11!) After showing proof-of-principle at LHCp in Paris (Nov 11), decided to combine results only after a discovery and at end of Run 1 14

15 LHC Higgs Combinations: Public Documents 15

16 Historic Joint ATLAS + CMS Run 1 Publications After the discovery and based on published Run 1 data Combined ATLAS + CMS Higgs mass measurement Combined ATLAS + CMS Higgs Coupling measurements 2016 Getting rival physicists to agree on common publication not easy Brought to completion in a seamless & timely fashion by Marco Pieri from CMS end Bravo! 16

17 Group s Run 2 Physics Plan New energy regime s = 13 TeV! Nature of the H 125 resonance established to be consistent with SM Higgs Will take much more s = 13 TeV data to do much better Hence our plan is to deemphasize our Higgs activities in early part of Run2 Focus on new physics searches with ~ 10 fb -1 at this new energy Target searches for possible pair produced Dark Matter at LHC and Invisible decays of H 125 Get back to substantially improving the Higgs portrait in the later half of Run 2 (2017) 17

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19 Hunting Dark Matter ( χ ) : The WIMP hypothesis Detection of DM essentially implies observing its interaction with known matter: χ + χ q + q There are broadly three classes of DM experiments depending on how we twist the legs of this interaction diagram χ q χ χ χ q χ q q q q χ Indirect Detection Direct Detection Production at Colliders All detection methods face pernicious backgrounds!

20 Mono-X Searches at LHC We chose to pursue the most sensitive final state: Mono-jets

21 DM Production Searches With CMS See next talk by Adish Vartak; recently appointed co-coordinator of CMS MET+X (Mono-X) search subgroup in CMS Exotica WG

22 Recognition For Our Run 1 Research 2016 APS Mitsuyoshi Tanaka Dissertation Award in Experimental Particle Physics "for contribution to the search and discovery of the Higgs boson and for his exemplary dissertation, entitled "Discovery of a Higgs boson in the H to ZZ to 4l Channel," covering Higgs physics, the details of his Higgs studies and other contributions to the CMS experiment." 22

23 Adish is 2 nd Tanaka Award Winner From This Group! Shahram Rahatlou: 2004 Tanaka Award "For his role in the development of the tools needed for the analysis of B factory data, including the tfit program, a unique and comprehensive fitting framework for timedependent analyses. The tools he developed played a key role in the observation of CP violation in the B system by the BaBar collaboration. These tools will be essential to the ongoing program of work as the B factories continue to probe the origins of CP violation." Now Professor at U. Rome and the incoming CMS Physics Coordinator 23

24 EPS Young Experimental Physicist Award (2015) Giovanni Petrucciani for his outstanding contributions to the optimization of the tracking in the CMS detector, the Higgs boson discovery and the measurements of its properties. Now a CERN Staff, awarded for all work done while a Postdoc with UCSD with Sharma group 24

25 MIT s Lee Grodzins Postdoctoral Fellows Lecture Award (2014) Giovanni Petrucciani has made original and unique contributions related to the discovery of the Higgs boson. Notably, Petrucciani was the architect of the comprehensive and complex statistical, and technical, framework for analyzing and combining the results from multiple Higgs study channels on the CMS and ATLAS experiments. Very satisfying, since MIT has been our major rival in CMS Physics! 25

26 Accelerated Promotion to UCSD Distinguished Professor (2014) Because of [Sharma s] extraordinary achievements, throughout his career, and most notably, his contributions to the detection and characterization of the Higgs Boson, CAP enthusiastically supports the advancement to Professor, Above Scale [Distinguished Professor] 26

27 Scientific Outreach: Reviews & Book Carena,Grojean, Kado, Sharma; 142 pages 27

28 Number of Downloads Monitored at LBNL Higgs boson Passage of particles through matter Plots of cross sections and related quantities Neutrino mass, mixing, and oscillations Electroweak model and constraints on new physics Particle detectors at accelerators Cosmic rays QCD Statistics Quark model Cosmological parameters Physical constants Kinematics CKM quarkmixing matrix Crosssection formulae Dark matter Dark energy Top quark Big bang cosmology Higgs review downloaded > 60,000 times Downloads 0 10,000 30,000 50,000

29 Annual Review Of Nuclear & Particle Sciences

30 Book Published by World Scientific: Arrives Oct 16 Book emphasizes pedagogy & written with chapters from young physicists from CMS and ATLAS who played star roles in Higgs discovery 30

31 Summary Small, extremely productive group in CMS that consistently identifies the most important and interesting topics to work on and has a proven record of executing them to perfection Higgs Search & Discovery Dark Matter Searches Tracking and Tracker 31