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Personal Recollections from. Gagan Mohanty. DHEP, TIFR. DHEP Seminar February 2, 2012. DHEP Seminar July 29, 2013. TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: A A A A A A A. Shall roughly follow the sequence given here . }. Man-made machines. - PowerPoint PPT Presentation
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DHEP Seminar February 2, 2012
Gagan MohantyDHEP, TIFR
Personal Recollections from
DHEP Seminar July 29, 2013
Shall roughly follow the sequence given here
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2o Focus on what I found interesting, detailed at http://www-conf.slac.stanford.edu/lp13
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Let’s start with QCD
Inclusive jet and dijet measurements
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Complimentary to inclusive jet measurement m12 is the dijet invariant mass and y is half
the absolute rapidity difference between the two leading jets
Data and theory are in agreement to ~10% with various PDFs
H.D. Yoo
s keeps on running...
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Ratio of the inclusive 3-jet to inclusive 2-jet cross section (R32) with the average pT of the two leading jets (<pT1,2>) ranging between 0.42 and 1.39 TeV
First determination of s from measurements at a Q value above 0.6 TeV Good agreement with the world average value of s(mZ) = 0.11840.0007
®s(mZ) = 0:1148§ 0:0014(exp:) § 0:0018(PDF)+0:0050¡ 0:0000(scale)
Similar results from ATLAS
H.D. Yoo
A text-book plot from CMS
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6 ATLAS has got a similar story to tell
( NLO and NNLO)
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A bit on hadron spectroscopy
Mass (3871.680.17 MeV): Close toD0D*0 threshold Width (< 1.2 MeV, CL=90%): Narrow Production
In pp/pp collisions – rate similar to charmoniaIn B decays – KX similar to cc, K*X smaller than cc
Decay BF: open charm ~ 50%, charmonia ~ few % Nature (very likely exotic)
LooselyD0D*0 bound state (like deuteron)? Mixture of excited c1 andD0D*0 bound state? Many other possibilities: tetraquark etc.?
Find out JPC assignment out of the remaining two possibilities: 1++ and 2+ to pin down its nature
M(+J/) –M(J/) [GeV]
Discovered in 2003
What is the X(3872)?
X(3872)(2S)
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C.Z. Yuan
9
313 26
JPC=2+ rejected at 8.2!
PRL 110, 222001 (2013)
JPC of the X(3872) is 1++
C.Z. Yuan
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Discovery of a new particle – Zc(3900)
• M = 3899.03.64.9 MeV• = 461020 MeV• 307 48 events• Significance >8
C.Z. Yuan
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What is Zc(3900)? Charged and couples to cc at least four-quark configuration
Clearly exotic – tetraquark, DD molecule, cusp…
PRL 110, 252002 (2013)PRL 110, 252001 (2013)
e+e +J/ at Ecm= 4.26 GeV e+e +J/ from ISR events
• M = 3894.56.64.5 MeV• = 632426 MeV• 159 49 events• Significance >5.2
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Charm, beauty and strange-beauty mesons
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12R. Oldeman
Probing CP violation in charm decays
Is it SM or NP? – a theorist prescription
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RSM is not expected to be greater than 1 for mc >> QCD, but not impossible if we treat the charm-quark to be light
J.F. Kamenik
Check:
Another enigma: semileptonic asymmetry
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14R. Oldeman
Bottom-line:
Current status of the Unitarity triangle
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®=Á2 = ¡88:5+4:7¡ 4:4
¢±
M. Roney
A tantalizing result on B D()
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If the discrepancy with SM holds up, the result cannot be explained by type-II 2HDM; excluded over the full parameter space at 99.8% CL
But can be accommodated in more general extensions of type-III 2HDM
M. Roney
PRL 109, 101802 (2012)
BaBar
Type-II 2HDM
Bs +: almost like a litmus test
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17 Highly sensitive to extended Higgs model and MSSM at large tan region
G. Mancinelli
First evidence for Bs +
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Consistent with the SM expectation (3.28109) Set an upper limit on BF(B0 +) < 9.41010 at 95% confidence level
G. Mancinelli
Recently CMS also came with a bang!
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U. Langenegger at EPS2013
arXiv:1307.5025[hep-ex]
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Let’s now go behind the truth!
Why to worry about measuring the top mass?
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The top quark decays well before hadronizing, so one can directly measure its mass by reconstructing various decay products
Indeed, top is the most accurately measured quark (better than 0.5%)
Participates in the quantum loop radiative corrections to the W mass, constraining the Higgs mass (was important till July 2012 discovery)
Now one can use this measurement to assess the self-consistency of SM
The huge mass (almost same as the tungsten atom) puts it close to the scale of EWSB, so the top quark might have a special role in it
So far the most sensitive method at LHC
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A. Castro
LHC average for the top mass
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What about Tevatron?
A. Castro
An unsettled question from Tevatron
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Thanks to pp environment, one can measure the forward-backward asymmetry AFB
J. Varela
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Story so far from the LHC Being a pp machine, LHC does not allow to measure AFB;
we can however measure the charge asymmetry Ac
J. Varela
Another SM candle: W mass
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Current WA is dominated by Tevatron and has a precision of 104B. Quinn
A picture perfect for ILC enthusiasts
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B. Quinn
Probing BSM with charged leptons
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Great prospect ahead to further pin down cLFV with the MEG upgrade, Mu2e, COMET, Project X and Belle II
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Now
Prohibitively small in SM+mass, so constitutes a clean BSM probe
S. Mihara
Neutrino mixing phenomenology
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S. Pascoli
One of the highlighted results on s: sin2(13)
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Y.F. Wang
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Now to the discovery of the decade!
The decay H → γγ: two approaches
Cut-based
Each event category is weighted by its S/(S+B)
only for visualization purposes 32
MVA method is the nominal one while the cut-based approach is there for the cross-check purpose
MVA mass-factorized
A. De Roeck
M(4l)>160 GeV Data 380 evts MC 364.5 evts
(pp ZZ, 8TeV) = 8.41.0 (stat.) 0.7 (syst.) 0.4(lum.) pb
Clean signal peak at ~126 GeV
Good control of the dominant ZZ background
SM(th) = 7.8 0.6 pb
The decay H → ZZ → 4l
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A. De Roeck
The decay H → WW → 2l+2νEvents with 0 jets and different flavour leptons (7+8 TeV Data)
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Exclusion at 95% in the mass range 128-600 GeVLarge excess (4 observed, 5.1 expected at mH 125 GeV) in the low mass region
A. De Roeck
Summary of the five main channels
bb: includes VH and VBFWW: includes ggF, VH, VBF
For a mass of mH = 125.7 GeV CMS-PAS-HIG-13-005
3.4
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Current result
Discovery paper
Expected Observed
3.8 3.2
2.8 4.1
2.4 1.6
1.9 0.7
1.4 0.0
PLB 716, 30-61 (2012)
A. De Roeck
Mass of the new boson
mH = 125.7 ± 0.3(stat) ± 0.3(syst) GeV = 125.7 ± 0.4 GeV
H ZZ4l: mH = 125.8 ± 0.5 (stat.) ±0.2 (syst.) GeVH γγ: mH = 125.4 ± 0.5 (stat.) ±0.6 (syst.) GeV
Signal strengthversus mass
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A. De Roeck
Couplings to fermions and gauge bosons
Overall result
Contributions from all decay channels
Results within 1σ of the SM prediction
For mH = 125.7 GeV(H gg) ~ | kV + kf|
2 / = 0.2, BSM = 0
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A. De Roeck
Discriminant built to describe the kinematics of production and decay of different JP state of a "Higgs"
0+ vs 0-
CLs=0.16%
More JP hypotheses have been tested in a similar way
What about its spin and parity?
Spin/parity hypothesis tests: H → ZZ → 4l channel
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A. De Roeck
Latest news on the Higgs from ATLAS
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7.4 6.6
3.8
1.1
K. Jakobs
ATLAS-CONF-2013-013
ATLAS-CONF-2012-161
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Significances reported in the Discovery paper: 4.5, 3.6 and 2.8 for gg, ZZ and WW
PLB 716, 1-29 (2012)
How does the Higgs couple to SM particles?
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K. Jakobs
Is it a scalar or pseudo-scalar?
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K. Jakobs
How likely it is a tensor (2+) particle?
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K. Jakobs
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Anything else I found interesting?
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C. Galbiati
M. Nicola
P. Zuccon
P. Privetera
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