Recent ATLAS Higgs Results and KoRIA 2 nd AKPA Physics Symposium January 20, 2012 Dr. Jaehoon Yu Outline • What is High Energy Physics? • Where are we at present with Higgs? • What have we seen in Higgs at the LHC? • What can we do with KoRIA?
Feb 22, 2016
Recent ATLAS Higgs Results and KoRIA2nd AKPA Physics Symposium
January 20, 2012Dr. Jaehoon Yu
Outline
• What is High Energy Physics?• Where are we at present with Higgs?• What have we seen in Higgs at the LHC?• What can we do with KoRIA?• Conclusions
Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
High Energy Physics• Definition: A field of physics that pursues understanding
the fundamental constituents of matter and basic principles of interactions between them.
• Known interactions (forces):– Gravitational– Electro-Weak– Strong
• Current theory: The Standard Model of Particle Physics– Unified Weak and Electromagnetic: SU(2)xU(1)– Strong Interaction: SU(3)– Currently:SU(3)xSU(2)xU(1)– Meaning: 8+4 mediators for forces
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Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
The Standard Model of Particle Physics • Prescribes the following fundamental structure:
• Three families of leptons and quarks together with 12 force mediators Simple and elegant!!!
• Tested to a precision of 1 part per million!
~0.1mp
Family
Discovered in 1995, ~175mp
Directly observed in 2000
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Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
Good, but still lots we don’t know…• Why are there three families of quarks and leptons?• Why is the mass range so large (0.1mp – 175 mp)?• How do matters acquire mass?
– Higgs mechanism but where is the Higgs, the God particle?• Why is the matter in the universe made only of particles?
– What happened to anti-particles? Or anti-matters?• Why are there only three apparent forces?• Is the picture we present the real thing?
– What makes up the 96% of the universe?– How about extra-dimensions?
• How is the universe created? • Are there any other theories that describe the universe better?
– Does the super-symmetry exist?
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Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
Fermilab Tevatron and LHC at CERN• World’s Highest Energy proton-anti-proton collider
– 4km circumference– Ecm=1.96 TeV (=6.3x10-7J/p 13M Joules on the
area smaller than 10-4m2)– Equivalent to the kinetic energy of a 20t truck at the
speed 81mi/hr 130km/hr• ~100,000 times the energy density at the ground 0 of the
Hiroshima atom bomb– Was shut down at 2pm CDT, Sept. 30, 2011
• Other parts of the complex is still running!!
Chicago
Tevatron p
p CDF DØ
• World’s Highest Energy p-p collider– 27km circumference, 100m underground– Design Ecm=14 TeV (=44x10-7J/p 362M
Joules on the area smaller than 10-4m2) Equivalent to the kinetic energy of a B727
(80tons) at the speed 193mi/hr 312km/hr ~3M times the energy density at the ground 0 of the
Hiroshima atom bomb• First 7TeV collisions on 3/30/10 The highest energy
humans ever achieved!!• First collisions in 2012 in mid March, 2012
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ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
ATLAS Detector
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• Weighs 7000 tons and 10 story tall• Can inspect 1,000,000,000 collisions/second• Records 200 – 400 collisions/second• Records approximately 350,000,000 bytes/second• Record 2x1015 (2,000,000,000,000,000) bytes each year (2
PetaByte). 200*Printed material of the US Lib. of Congress
Jan. 20, 2012
Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
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ATLAS Integrated Luminosity in 2011
LHC delivered 2010 - 2011: 5615 pb-1
ATLAS recorded 2010 - 2011: 5252pb-1
ATLAS data taking ε: 94%About 160 times the data taken in 2010!!1700pb-1 in one month!! 2012 expects close to 10,000pb-1
ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
Pixel module
Cooling pipe
Cables
C-fibershell
Data Simulation
Step one: Understanding the ATLAS Detector
Allows detailed understanding of the detector material via location of interactions.
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ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu 9
• Important first steps are the verification of the Standard Model physics at √s = 7 TeV • W/Z weak vector boson are powerful tools to constrain PDF’s and to understand detector
Step two: Verify SM Weak Bosons
Jan. 20, 20129
ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
Of course, we see Z ee and μμ!!Z ee candidate
Total efficiency : ~ 30% Main background: QCD S/B ~ 100
Z μμ candidate
Total efficiency: ~ 40%Main background: tt, Z ττ S/B ~ 400
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ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
Step 3: Understanding SM background to Higgs!!
Jan. 20, 2012 11
W x-sec vs CMS EnergyW+Njet x-sec
Validation of theoretical predictions!!
ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
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Higgs x-sec and Branching Ratio130GeV
ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
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ATLAS Higgs Search Strategy• Use production
– MH<130GeV• dominant decay
– High QCD background• cleanest but low BR• with leptonic decays of t Small branching ratio
– 130GeV<MH<2MZ:– MH>2MZ:
• Use multi-lepton final state from decays of bosons• final state dominated by QCD production of top.
• Use WH or ZH production at low mass (MH<120GeV)– Use leptonic decay of bosons with two b-jets.
H bb
gg H
* *, H WW H ZZ
H H t t
, , H WW H ZZ H tt
tt
Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
LEP EWWG:http://www.cern.ch/LEPEWWG 114<MH<300+700-186 GeV
What do we know on Higgs before LHC?
MW ~ M t2 ln MH
2( )
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ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
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• Higgs boson is a ramification of the mass generation mechanism Highest priority in HEP and the last standing mystery
• Higgs decays in to various final states – H ZZ* 4e, 2e2μ and 2e2n – Very clean signal w/ modest background– Narrow mass peak– High PT electron identification key
Golden Channels in Higgs Searches
e- (μ-)e+ (μ+)
e-
e+
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After all selections: kinematic cuts, γ identification and isolation
22489 events with 100 < mγγ < 160 GeV observed in the data expected signal efficiency: ~ 35% for mH=125 GeV
mγγ spectrum fit with exponential function for background plus Crystal Ball + Gaussian for signalbackground determined directly from data
Main systematic uncertainties
Expected signal yield : ~ 20%H γγ mass resolution : ~ 14%H γγ pT modeling : ~ 8% Background modeling : ±0.1-5.6 events
Systematic uncertainties on signal expectation
Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
Maximum deviation from background-onlyexpectation observed for mH~126 GeV: local p0-value: 0.27% or 2.8σ expected from SM Higgs: ~ 1.4σ local global p0-value: includes probability for such an excess to appear anywhere in the investigated mass range 110-150 GeV (“Look-Elsewhere-Effect”): ~7% (1.5σ)
Consistency of the data with thebackground-only expectation
Excluded (95% CL):114 ≤ mH ≤ 115 GeV, 135 ≤ mH≤ 136 GeV
Expected from SMHiggs at given mH
Where are we with Higgs searches?LEP
ATLAS+CMSCombination
ATLAStoday
Higgs could be discovered this year!!
Jan. 20, 2012 18ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
ATLAS Higgs in 2012??
Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
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We could find the Higgs particle at the LHC this year!!Once found, the precision measurement of the Higgs becomes very important!!
Jan. 20, 2012
A Future Linear Collider• An electron-positron collider on a straight line for precision
measurements• CMS Energy: 0.5 – 1 TeV• 10~15 years from now (Japanese PM announced that they would bid
for a LC in Japan)• Takes 10 years to build the accelerator and the detector
L~31km
ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
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Circumference ~6.6km~300 soccer fields
From CERN-open-2000-344, A. Sharma
GEM foil etching
70μm140μm
Gas Electron Multipliers (GEM)
GEM field and multiplication
Gains
Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
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100cmx100cm GEM Planes!!CERN GDD Workshop delivered the first 5 of 33cmx100cm GEM foils in 2010 Qualification completed!!
GEM DHCAL, J. Yu 22
Each of the GEM 100cmx100cm planes will consist of three 33cmx100cm unit chambers
Sept. 29, 2011
Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
GEM Application Potential FAST X-RAY IMAGING
Using the lower GEM signal, the readout can be self-triggered with energy discrimination:
A. Bressan et al, Nucl. Instr. and Meth. A 425(1999)254F. Sauli, Nucl. Instr. and Meth.A 461(2001)47
9 keV absorption radiography of a small mammal (image size ~ 60 x 30 mm2)
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Radioactive Source Run with Internal Trigger
Jan. 20, 2012 24ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
Noisy channels masked out!
Can you see what the object is?
And in not too distant future, we could do …
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KoRIA, A World-class Accelerator Facility• Future high priority high energy physics topics will require
even higher energy and higher flux– Searching and precisely measuring the properties of SUSY
particles, dark matter, dark Energy and extra dimensions– Massive detailed studies of quark-gluon plasma!– Creating and accumulating anti-matters in mass!!
• KoRIA is a great starting point for establishing a versatile world-class accelerator facility in Korea
• Attract large number of scientists and promote advancement of accelerator related technologies
• Advance significantly the understanding the origin of the universe and help the whole human race in the long runJan. 20, 2012 26ATLAS Higgs, HEP
and KoRIA Dr. Jaehoon Yu
So how can KORIA get there?• The current KoRIA must be solidly established and carry out
its mission successfully • A clear vision for the long-term future of KoRIA must be
established from the get-go• Phased plan must be established to shape the future of
KoRIA even as the current KoRIA is being constructed• Build up manpower through the strong collaboration with
existing labs, such as Fermilab and CERN– Train domestically to increase technical manpower
• A stage for a historic future is set!• Need to get organized now to make it happen in 30yrs!
Jan. 20, 2012 27ATLAS Higgs, HEP and KoRIA Dr.
Jaehoon Yu
Conclusions• The LHC opened up a whole new kinematic regime
– The LHC performed extremely well this year• 1fb-1 expected but obtained over 5fb-1
• Latest results on Higgs show some hints of its existence – We expect over 10fb-1 additional data expected 2012
• We could find the Higgs particle this year or disprove its existence– In 2013 – 2014, an 18 month work on the accelerator toward the designed 14TeV
• Linear collider and advanced detectors are being developed for future precision measurements of Higgs and other newly discovered particles
• Outcome and the bi-product of HEP research impacts our daily lives – WWW came from HEP– GEM will make a large screen low dosage X-ray imaging possible
• KoRIA is a fruit of aspiration for excellence in basic sciences– Need to plan now to shape KoRIA to its long term future and to realize the dream
• Strong US-Korea collaboration will help this happen
Jan. 20, 2012 ATLAS Higgs, HEP and KoRIA Dr. Jaehoon Yu
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KoRIA in 30 years?
Jan. 20, 2012 29ATLAS Higgs, HEP and KoRIA Dr.
Jaehoon Yu
15 kilometers
Booster complex