selected results from ichep
DESCRIPTION
P. Grannis DØ Workshop 2012. Selected results from ICHEP. Many new results from LHC, Tevatron, neutrino experiments, etc. Tevatron results received good coverage but I will not focus on them here. I cover mainly the experimental results. - PowerPoint PPT PresentationTRANSCRIPT
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Selected results from ICHEP
P. Grannis
DØ Workshop 2012
Many new results from LHC, Tevatron, neutrino experiments, etc. Tevatron results received good coverage but I will not focus on them here. I cover mainly the experimental results.
Note that the LHC pp running has now been extended to the end of calendar 2012. Current projections suggest the 2012 data set will be in the 35 – 50 fb-1 range.
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Pileup at LHC
Algorithms developed in ATLAS and CMS mitigate the pileup effects
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Higgs results: (1) (Talks by R. Hawkings & J. Incandela)
Local significance (125 GeV)=4.1
Local significance (125 GeV) =4.5(after ES syst.)
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Higgs results: (2) ZZ* (4l)
Local significance (125 GeV) =3.4
Local significance (125.5 GeV) =3.2
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Higgs analysis improvements in 2012 ATLAS: analysis in 10 subcategories of conversions, pT
, , 2 jets NN ID pointing to PV energy scale calibration background fitting Allow FSR in ZZ Intermediate muonsCMS: Diphoton MVA Add VBF 2 photon subchannel; 4 categories of FSR recovery for ZZ Matrix element likelihood for ZZ and 2-dim ME vs Mllll
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Current LHC H→bb/ situation
CMS has reached 95%/SM ≈2 at 125 GeV.
bb
signal below expectation of Bknd only
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Final Atlas and CMS combinations
CMS Uses updated VH→bb, , , ZZ, WW(ll) ; They call attention to deficit of H→ff relative to H →VV 4.9 at 125.3 GeV (5.9 exp)
ATLAS: VH→bb, , WW not updated from 2011. 5.1 at 126.5 GeV (4.6 exp)
Note: 125 GeV SM Higgs tends to violate vacuum stability bound at scales above ~108 GeV.
125 GeV
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Top quark (T. Muller)
LHC tt pair XS to 6 – 8%
New CMS result at 8 TeVAsymmetry:
tt resonances: none to ~1.5 TeV
ATLAS sees Wt single top to ~3
Single top
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Top quark
ATLAS W helicity fractions to ~5%, now approaching Tevatron precision.
Top mass
CMS
LHC approaching Tevatron precision
World’s best
top-antitop mass difference
ttZ production (CMS)
4.67
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Electroweak (J. Guimaraes da Costa)Atlas/CMS W/Z production cross sections in good agreement with SM and lepton universality at 8 TeV.
LHCb extends W/Z XS and W asymmetry to large yV, giving useful data for PDF constraints.
ATLAS/CMS + HERA fits give average strange quark density = dbar density.
Drell Yan d2/dMdy shows low mass data deficit relative to POWHEG/FEWZ
pTZ comparison to ResBos resembles D0
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Electroweak
TGCs: LHC now surpassing WW/WWZ limits, still below Tevatron for ZZ/Z
AFB in Z agrees with SM
CMS uncertainty in sin2W (light quarks) of 0.003 (D0 error is 0.001)
Congratulations to Tevatron on W mass! Challenging outlook for LHC.
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SUSY Searches (A. Parker )
Golden channels (jets + MET) show no hint; exclusion for equal squark/gluino mass at ~1.5 TeV
Look in corners of phase space; e.g. light stop. Not yet very constraining. (125 GeV Higgs makes light stop difficult)
Stealth SUSY – e.g. low mass hidden sector gives many low pT final objects. Search in ST
R. Sundrum: “Is SUSY dead? No, but somewhat humbled”. 125 GeV Higgs makes SUSY morecomplex/fine-tuned. At mH=125, SUSY breaking terms ~ MZ . But SUSY is so beautiful reluctant to give up.
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Non SUSY BSM Searches (S. Worm)
About 50 LHC searches for new phenomena in different signatures/models. Nothing seen.
No Z’ to ~ 2.5 TeV, no W’ to ~2.8 TeV; no dijet resonance to ~ 3.5 TeV; no miniBH to ~4.5 TeV
ATLAS seeks magnetic monopoles in DY production using TRT ionization, hit multiplicities, calorimeter; none 0.2 – 1.2 TeV
LED scale limits from monojets and monophotons.
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New Physics in heavy flavor (S. Stone)
s in J/; New results from ATLAS, LHCbLHCb avg: s = 0.002±0.088
LHCb from J/ : s = 0.019 ±0.174
Asl = asymmetry in B(s) → D(s) X
LHCb: asls =
0.24±0.63%
Bfact: asld =
0.05±0.56%D0: asls = 1.81±0.56%
D0: asld = 0.22±0.30%
Reviewer makes the point LHCb agrees w/ SM, D0 does not. But D0 as
sl & adsl
agree with LHCb/Bfactories and agree with D0 dimuon asymmetry, which does not agree with SM
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New Physics in heavy flavor
Bs →
New limits from CMS and LHCb; 1.2xSM value. Tightens limit on SUSY models (tan < 50)
Previous discrepancy with B+→ now coming closer to SM
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CKM Measurements: (M. Nakao)
New Belle measurement of B→reduces discrepancy with SM.
CPV in difference of A(D0→K+K and A(D0→) seen in 4 expts. Now 4.
World avg CPV in D+→Ks is now 0.41±0.09%.
Recent BaBAR CPV in →Ks+ (n0) is now 2.8 from SM
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Rare decays (Y. Kuno)
Recent results:
→e (MEG expt); 2009-10 data: BR<2.4x10 (expect 1x10with 2011 data).
(NA48/NA62): (K→e/(K→ 2.49±0.01 x10
E787/E949: K+→: 17.3±11 x10 (7.2x10 SM)
LHCb: D→ < 1.1 x10Future expt’s: COMET (JParc) and Mu2e (FNAL) for →e conversion at the 10 level
NA62 (CERN): K+→(10% BR)
ORKA (FNAL): K+→ (5% BR)
Future facilities:
SuperKEKb, SuperB Factories; LHC lumi upgrade; Intensity upgrade at Fermilab, Project X;
Rare decays are sensitive to new physics well beyond LHC scale.
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QCD Jets (D. Bandurin) JES uncertainty at LHC now in 2-4% range (~2xD0)
Comparison of inclusive jets at 7 and 8 TeV; now offer strong constraints on PDFs.
Need precise s to constrain PDFs, make XS predictions, check coupling unification; new D0 data improve precision.
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QCD Jets
New LHC Z/W+jets (light flavor and b).
ATLAS W+b XS ~2xSM (CDF was 3xSM), +jets measurements at LHC show similar agreement/disagreement with NLO QCD as seen at Tevatron.
Double parton scattering: new ATLAS results show continued trend to slowly increasing eff with energy.
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The LHC data favor sea quark ‘democracy’ (s, sbar, dbar the same). Previous x(s) situation was chaotic.
ATLAS/CMS W/Z total, differential XS’s are constraining PDFs.
Recent HERA analyses have improved constraints on c and b PDFs.
PDFs (S. Glazov)
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Elastic/Diffraction: (P. Newman)
TOTEM (Roman Pots) measures d/dt for pp (7 TeV). Relative to D0 measurement, the dip moves from t=0.6 to 0.53 and slope increases from 16.7 to 19.9 GeV-2, reflecting the growth effictive proton size.
TOTEM extrapolates from data at t=-0.005 to zero and invokes optical theorem to get TOT =98.3 mb. Total cross section growing like ln2s consistent with Froissart Bound.
CMS rapidity gap measurement shows ‘survival probability’ in agreement with Tevatron (at variance with HERA).
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New heavy quark states: (R. Mizuk)
Many new results – see talk for details.
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Reactor Neutrinos: (Jun Cao)Anti e disappearance from reactor experiments is sensitive to sin2213 : no complications from mass hierarchy, matter effects, CPV. For Daya Bay, RENO (soon dCHOOZ) measure in near and far detectors to reduce systematics.
Best estimates of background rates are ~2(5)% at near (far) detector.
Observation that sin2213 is ‘large’ and non-zero is big news, even if overshadowed in ICHEP by ‘Higgs’ announcement. It allows the program to probe mass hierarchy and CPV.
Two fits with extreme priors on flux:
13 =9.2±0.46o or 8.7±0.45o
(from C. Gonzalez-Garcia talk)
Daya Bay
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Accelerator Neutrinos: (T. Kobayashi)Start with dominantly beam and look for e appearance
Updated T2K: 3.2
MINOS measurements on 23 now show slight tendancy for 23 ≠45o.
appearance: OPERA 2 evts with 0.2 bknd
SuperK: 3.8 away from no appearance
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Dark Matter: (L. Hsu)
Best limits at ICHEP on spin independent Wimp interactions is Xenon100 and reaches into the SUSY LSP space.
Post ICHEP press release (7/18) gives Xenon100 2012 result which has 2 events in window with 1 bknd expected. The limits are reduced by a factor 3.5.
There are enough conflicting claims in the DM world that we will need at least two strong confirming experiments using different techniques (ionization, scintillation light, phonons)
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Conclusion
It was an exciting meeting with many striking new results. The LHC has come of age.
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Conclusion
It was an exciting meeting with many striking new results. The LHC has come of age.
If one applies a Random Forest filter on Christian’s photo, a striking new discovery emerges at more than 5
Tevatron LHC