Strong Interactions and New Physics - LHC and operation (run-I, - - PowerPoint PPT Presentation

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Strong Interactions and New Physics - LHC and operation (run-I, - - PowerPoint PPT Presentation

Results from ATLAS and CMS: Strong Interactions and New Physics - LHC and operation (run-I, run-II) - ATLAS detector - QCD - top-quark - Heavy Ion - new physics (BSM, Exotica) complementary ATLAS & CMS presentations at this workshop:


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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

  • LHC and operation (run-I, run-II)
  • ATLAS detector
  • QCD
  • top-quark
  • Heavy Ion
  • new physics (BSM, Exotica)

Results from ATLAS and CMS: Strong Interactions and New Physics

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complementary ATLAS & CMS presentations at this workshop:

  • Paolo Azzurri:

Results from CMS and ATLAS: Electroweak Symmetry Breaking and Beyond

  • Roman Lysak:

Soft QCD topics from ATLAS

  • Michael Ryan Clark:

the Ridge and BE-correlations with ATLAS

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 2

LHC operation

June 2015: LHC back in business with record p-p-collision energy of 13 TeV c.m.

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

LHC operation

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run-I : → 2012, ~25 fb-1 @ 7/8 TeV LS-I : 2013/14, maint. & energy upgrade > 106 working hours in LHC tunnel run-II : 2015, ~4 fb-1 @ 13 TeV 2015-2018: ~100 fb-1 @ 13/14 TeV LS-II : 2019/20 hl-LHC civil engineering run-III : 2021-23, ~200 fb-1 @ 13/14 TeV

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

ATLAS detector

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Length: 44 m Height: 25 m Weight: 7000 t 3000 Physicists & Engineers (incl. 1000 Students) 38 Nations, 178 Institutes ~500 papers published 150•106 electronic readout channels 40 MHz collision rate 1014 B/s raw data flux

Planning & construction 1990 to 2007, operation from 2009 to ~ 2035

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

ATLAS detector

Di‐Jet Event

Highest Mass Central Dijet pT1 = pT2 = 3.2 TeV mJJ = 6.9 TeV MET =46GeV

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 6

production cross sections at the LHC

proton - (anti-)proton cross sections

total cross section: 108 evts/s (dominated

by strong interaction)

  • max. read-out:

~ 103 evts/sec O(1) top-event/sec O(1) Higgs/min

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 7

production cross sections at the LHC

(CMS)

cross section ratios 13 TeV / 8 TeV

  • for SM processes (top-quark; Higgs): x-sections increase by ~2…3 at 13 TeV
  • for new phenomena and masses of O(TeV), increase of ~10 to 100s
  • therefor, some early results from run-II already surpass those from run-I
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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

Inelastic pp cross section

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ATLAS ¡measurement ¡at ¡13TeV ¡performed ¡using ¡ ¡ Minimum ¡Bias ¡Trigger ¡Scin:llators ¡(MBTS) ¡ ¡ mounted ¡in ¡front ¡of ¡the ¡forward ¡calorimeters ¡

ATLAS-Conf-2015-038

Total ¡cross ¡sec:on: ¡ σinel. ¡= ¡73.1 ¡± ¡0.9 ¡(exp) ¡± ¡6.6 ¡(lumi) ¡± ¡3.8 ¡(extr) ¡mb ¡

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

Charged Particle Multiplicities and Correlations

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measurement ¡of ¡pseudorapidity ¡distribu:on ¡

  • f ¡charged ¡hadrons, ¡data ¡consistent ¡with ¡

expected ¡dependence ¡on ¡centre-­‑of-­‑mass ¡

  • energy. ¡Published ¡in ¡PLB ¡751 ¡(2015) ¡143. ¡ ¡

two-­‑par:cle ¡correla:ons, ¡confirming ¡the ¡ presence ¡of ¡a ¡ridge-­‑like ¡structure ¡for ¡same-­‑side ¡ (Δφ ¡~ ¡0) ¡pairs ¡in ¡high-­‑mul:plicity ¡events ¡at ¡13 ¡

  • TeV. ¡(arXiv:1510.03068) ¡ ¡

Also ¡reported ¡by ¡ATLAS ¡(arXiv:1509.04776), ¡ see ¡Michael ¡Clark’s ¡talk

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

Inclusive Jet Cross Sections

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  • inclusive ¡jet ¡produc:on ¡cross ¡sec:on ¡

¡ ¡ ¡ ¡in ¡bins ¡of ¡pT ¡and ¡y ¡

  • an:-­‑kT ¡jets; ¡R=0.4 ¡
  • good ¡agreement ¡with ¡predic:ons ¡

CMS-PAS-SMP-15-007 ATLAS-CONF-2015-034

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

Z+jets Production (jet multiplicities)

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  • Z+jets ¡is ¡important ¡background ¡to ¡many ¡

¡ ¡ ¡ ¡Beyond ¡Standard ¡Model ¡(BSM) ¡searches ¡ ¡ ¡ ¡ ¡and ¡Higgs ¡studies ¡! ¡

  • an:-­‑kT ¡jets; ¡R=0.4 ¡
  • good ¡agreement ¡with ¡predic:ons ¡(NLO ¡QCD ¡MC ¡+ ¡parton ¡shower) ¡

ATLAS-CONF-2015-041 CMS-PAS-SMP-15-010

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 12

determinations of αs

all hadron collider (except ttbar) and HERA results in NLO LEP, PETRA and ttbar in NNLO

compilation by CMS:

  • Eur. Phys. J. C75 (2015) 5, 186)

LHC and Tevatron results average to: αs(MZ)= 0.1172 ± 0.0059

not shown: ATLAS incl. jet: αs(MZ)= 0.115 ± 0.009 ATLAS TEEC: αs(MZ)= 0.1173 + 0.0066 - 0.0028 ATLAS ATEEC: αs(MZ)= 0.1195 + 0.0065 - 0.0028

  • Phys. Lett. B750, 427
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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 13

CMS: αs from ttbar cross section at sqrt(s)=7 TeV (in NNLO + NNLL)

→ relevant for 2016 RPP

Phys.Lett.B728 (2014) 496

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 14

more data available on ttbar cross section; preliminary estimates on αs :

(S. Bethke, G. Dissertori, T. Klijnsma and G. Salam, arXiv:1512.05194 [hep-ph] )

Newer results point to somewhat larger αs(MZ) than earlier CMS extraction (prelim: 0.1187–0.1201 v. 0.1151)

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 15

preliminary 2016 world average of αs

αs(Mz) = 0.1181 ± 0.0013

without hadron collider: αs(Mz) = 0.1183 ± 0.0014

  • S. Bethke, G. Dissertori, G. Salam in: 2016 edition of PDG’s RPP

(ttbar x-sect)

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 16

Top Quark Physics

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

Top Quark Physics

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  • Top-Quark: the heaviest known fundamental particle

2014 world combination of top-mass: mt = 173.34±0.27(stat)±0.73(sys) GeV arXiv:1403.4427


  • it decays before hadronisation, so its properties directly transfer to

its decay products

  • perfect candidate for precision tests of Standard Model

and also for searches of physics BSM

  • also dominates Higgs-production (through gluon-fusion)

strong: ttbar pair prod. electroweak: single t prod.

t-channel s-channel Wt

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 18

Top Quark Physics

production cross sections

arXiv:1510.05302 ATLAS-CONF-2015-079 ATLAS-CONF-2015-049 CMS-PAS-TOP-15-004

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 19

Top Quark Physics

mass determination

  • standard measurements are based on template methods

– adjust MC-defined top-quark mass to data

– relation between MC-defined and theoretical pole mass intensively discussed, argued to be close or even identical.

arXiv:1509.04044

world ave (2014): mt = 173.3±0.8 GeV ATLAS (2015): mt = 173.0±0.9 GeV CMS (2015): mt = 172.4±0.5 GeV

“direct mass”

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 20

Top Quark Physics

mass determination

“direct” (MC) mass and (theoretically well defined) pole mass agree within uncertainties (currently <~2 GeV)

  • measurements of pole mass through σtt become increasingly precise
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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

Heavy Ion Physics

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 22

Heavy Ion Physics

2015: Pb-Pb collisions at √(sNN) = 5.00 TeV (√(sPbPb) = 1.1 PeV) data taken in Nov/Dec 2015; no results with new data published yet study of the hot and dense medium produced in h.e. ion collisions

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 23

Heavy Ion Physics

jet suppression in PbPb collisions at sqrt(s[NN]) = 2.76 TeV ➔ significant suppression of jets (50%) observed for Pb-Pb central collisions (large Npart )

Phys.Rev.Lett. 114 (2015) 072302

RAA: jet nucleon modification factor; ratio of yields (heavy ion / pp) Npart: number of participating nucleons in heavy ion collisions (most central) (peripheral)

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 24

Heavy Ion Physics

  • Phys. Rev. C 90 (2014) 024908

arXiv:1406.0932 [nucl-ex]

jet fragmentation in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV peripheral central pT of charged particles inside jet cone (100 <pTjet < 300 GeV) ➔ significant enhancement of fragmentation function of charged particles with pT<3 GeV in most central Pb-Pb-collisions

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 25

Searches for New Phenomena

highest mass dimuon event (mμμ = 1.46 TeV)

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 26

Searches for New Phenomena

run-I data (7 and 8 TeV): no positive signals ➔ mass range exclusions

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 27

Searches for New Phenomena

CMS Exotica Physics Group Summary – Moriond, 2015!

stopped gluino (cloud) stopped stop (cloud) HSCP gluino (cloud) HSCP stop (cloud) q=2/3e HSCP q=3e HSCP chargino, ctau>100ns, AMSB neutralino, ctau=25cm, ECAL time

1 2 3 4 RS1(γγ), k=0.1 RS1(ee,μμ), k=0.1 RS1(jj), k=0.1 RS1(WW→4j), k=0.1 1 2 3 4 coloron(jj) x2 coloron(4j) x2 gluino(3j) x2 gluino(jjb) x2 1 2 3 4

RS Gravitons Multijet Resonances Long-Lived Particles

SSM Z'(ττ) SSM Z'(jj) SSM Z'(bb) SSM Z'(ee)+Z'(µµ) SSM W'(jj) SSM W'(lv) SSM W'(WZ→lvll) SSM W'(WZ→4j) 1 2 3 4

Heavy Gauge Bosons

CMS Preliminary

j+MET, vector DM=100 GeV, Λ j+MET, axial-vector DM=100 GeV, Λ j+MET, scalar DM=100 GeV, Λ γ+MET, vector DM=100 GeV, Λ γ+MET, axial-vector DM=100 GeV, Λ l+MET, ξ=+1, SI/SD DM=100 GeV, Λ l+MET, ξ=-1, SI/SD DM=100 GeV, Λ l+MET, ξ=0, SI/SD DM=100 GeV, Λ

1 2 3 4

Dark Matter

LQ1(ej) x2 LQ1(ej)+LQ1(νj) LQ2(μj) x2 LQ2(μj)+LQ2(νj) LQ3(νb) x2 LQ3(τb) x2 LQ3(τt) x2 LQ3(vt) x2 Single LQ1 (λ=1) Single LQ2 (λ=1)

1 2 3 4

Leptoquarks

e* (M=Λ) μ* (M=Λ) q* (qg) q* (qγ) b* 1 2 3 4

Excited Fermions

dijets, Λ+ LL/RR dijets, Λ- LL/RR dimuons, Λ+ LLIM dimuons, Λ- LLIM dielectrons, Λ+ LLIM dielectrons, Λ- LLIM single e, Λ HnCM single μ, Λ HnCM inclusive jets, Λ+ inclusive jets, Λ- 0 1 2 3 4 5 6 7 8 9 101112131415161718192021

ADD (γ+MET), nED=4, MD ADD (j+MET), nED=4, MD ADD (ee,μμ), nED=4, MS ADD (γγ), nED=4, MS ADD (jj), nED=4, MS QBH, nED=4, MD=4 TeV NR BH, nED=4, MD=4 TeV QBH (jj), nED=4, MD=4 TeV Jet Extinction Scale String Scale (jj)

1 2 3 4 5 6 7 8 9

Large Extra Dimensions Compositeness

TeV TeV TeV TeV TeV TeV TeV TeV TeV

run-I data (7 and 8 TeV): no positive signals ➔ mass range exclusions

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

Searches for New Phenomena

13 TeV data: Dijet Resonant Searches

28 arXiv:1512.01530v4 [hep-ex]

excludes e.g. excited quarks with masses < 5.2 TeV, and quantum BHs with masses < 5.1 … 8.3 TeV

CMS-EXO-15-001

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 29

Searches for New Phenomena

Dilepton Resonance Search

excludes e.g. Z’ with mZ’ < 3.4 TeV, and llqq contact interactions with scales Λllqq < 20 TeV excludes W’➝lν with mW’ < 4.4TeV

13 TeV data: Search for Heavy Gauge Bosons (Z’ and W’)

Lepton plus missing ET

CMS-PAS-EXO-15-006 ATLAS-CONF-2015-070

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 30

Searches for New Phenomena

Diboson Resonant Searches

modest excess observed in run-I: 3.4 σ local, 2.5 σ global significance no excess observed, but sensitivity still too low for conclusive probe (similar for CMS)

ATLAS-CONF-2015-073 arXiv:1506.00962

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 31

Searches for New Phenomena

13 TeV data: Diphoton Resonant Searches

– mγγ resolution: ~1% (ATLAS) ~1.1 / 1.8 % (CMS)

search for narrow width (Higgs-like) resonance

search for narrow to wide width (graviton-like) resonance

– different bin sizes: 40 GeV (ATLAS) 20 GeV (CMS)

ATLAS-CONF-2015-081 CMS-PAS-EXO-15-004

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 32

Searches for New Phenomena

13 TeV data: Diphoton Resonant Searches

local p-value: 2.6 σ at 760 GeV global p-value: <1.2 σ (500-4500 GeV)

[for narrow width assumption (Γ ~ 0.1 GeV)]

local p-value: 3.6 σ at 750 GeV global p-value: 2.0 σ (200-2000 GeV)

[for narrow width assumption (Γ ~ 0.004 GeV)

best fit (largest p-value): Γ~45 GeV, p-value 3.9 (2.3) σ

for large width (Γ ~ 42 GeV):

p-value 2.0 (< 1) σ

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 33

Searches for New Phenomena

13 TeV data: Diphoton Resonant Searches Consisteny Check with 8 TeV data

  • CMS: combined analysis improves 13 TeV limits :

local significane: 3.05 σ ; global significance: < 1.7 σ

  • ATLAS: repeated analysis of 8 TeV data with same conditions as at 13 TeV;

➔ results for narrow-width hypothesis and a spin-0 object from gg-fusion are consistent at 2.2 σ level (1.4 σ for Γ/m = 6%)

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016

Summary

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  • run II at √s = 13 TeV successfully started in 2015
  • results from new 2015 data significantly extend and -

in some cases - already exceed results obtained from run-I data (√s = 7 and 8 TeV)

  • SM still in very good shape at 13 TeV
  • precision results for fundamental SM parameters like

mtop, αs, σtop … (Higgs: see talk by Paolo Azzurri)

  • modest excess signal seen in run-I di-boson mass (and
  • thers) need more statistics
  • modest “bump” in mγγ distribution at ~750 GeV

boosts hopes and imagination - desperately waiting for more data!

  • no significant signal of physics BSM seen; some limits

from run-II already exceed those from run-I

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ATLAS & CMS: Strong Interactions and New Physics S.Bethke, MPP München Bormio 2016 35

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