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Bill Gabella and Med Webster QuarkNet 2013 Vanderbilt University. Compact Muon Solenoid (CMS) Physics, Status, and Plans. Outline. The Standard Model of Particle Physics The Large Hadron Collider The Compact Muon Solenoid Proton on Proton collisions - PowerPoint PPT Presentation
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Compact Muon Solenoid (CMS) Physics, Compact Muon Solenoid (CMS) Physics, Status, and PlansStatus, and Plans
Bill Gabella and Med Webster
QuarkNet 2013Vanderbilt University
8 July 2013 Gabella CMS Status 2
– The Standard Model of Particle Physics– The Large Hadron Collider– The Compact Muon Solenoid– Proton on Proton collisions
● Higgs Boson, now your run-of-the-mill Standard Model Higgs● Supersymmetry, NOT?● Extra Dimensions
– Lead on Lead collisions● centrality, Jet Quenching● ridge in two particle correlations
– Large Hadron Collider and CMS plans
OutlineOutline
8 July 2013 Gabella CMS Status 3
Particle Physics,Particle Physics,aka High-Energy Physics,aka High-Energy Physics,
aka Theory of Fundamental Particlesaka Theory of Fundamental Particles
Yes, but protons andneutrons are also madeup of Quarks!
All stable matter is madeof protons, neutrons, andelectrons.
8 July 2013 Gabella CMS Status 4
The Standard ModelThe Standard ModelA good description of fundamental particle interactions, relevant inside thenucleus, at early times in the evolution of the universe, and in man-madeand natural collisions of particles.
Particles that make up Matter. Particles that “carry” the force.
All of the matter and forces in the Universe are made up of:6 leptons (and 6 anti-leptons), 6 quarks (and 6 anti-quarks), and 12 force carryingparticles...ur plus the Higgs boson and don't forget Gravity, and...
8 July 2013 Gabella CMS Status 5
8 July 2013 Gabella CMS Status 6
Ref: http://www.particleadventure.org
8 July 2013 Gabella CMS Status 7
Cosmic Ray Cosmic Ray ShowersShowers
Ref: http://www.particleadventure.org
Mostly Protons withhigh energy hittingthe atmosphere...make mostly muonsat Earth.
8 July 2013 Gabella CMS Status 8
Particle AcceleratorsParticle Accelerators
Tevatron, was p on p-barBatavia, IL (Chicago)2 TeV center of massnow lower energy, high intensity psource, also intense neutrino source
Large Hadron Collider, p on pGeneva, Switzerland7, 8, and soon 14 TeVcenter of mass
Ref: www.fnal.gov, www.cern.ch
8 July 2013 Gabella CMS Status 9
The Large Hadron ColliderThe Large Hadron ColliderProton-on-Proton collider, 2010-11 3.5+3.5 TeV center of mass energy 2012 4+4 TeV plan 2015 7+7 TeValso Lead-on-Lead (aka Heavy Ion) colliderand Proton-on-Lead for comparison of the above two
8 July 2013 Gabella CMS Status 10
The Large Hadron ColliderThe Large Hadron Collider
8 July 2013 Gabella CMS Status 11
The Large Hadron ColliderThe Large Hadron Collider
8 July 2013 Gabella CMS Status 12
Large Hadron Collider (LHC)Large Hadron Collider (LHC)
Energies:
Linac 50 MeV
PSB 1.4 GeV
PS 28 GeV
SPS 450 GeV
LHC 3.5, 4, 7 TeV
Ref: Introduction to Accelerators, Elena Wildner, CERN
8 July 2013 Gabella CMS Status 13
CMS DetectorCMS Detector
http://www.uscms.org/public_2/about/cms_detector/index.shtml
Vanderbilt University (Will Johns)
Gabella CMS Status8 July 2013 14
Particles through a CMS sliceParticles through a CMS slice
8 July 2013 Gabella CMS Status 15
The Forward and Barrel Pixel DetectorThe Forward and Barrel Pixel Detector
borrowed from Mauro Dinardo docdb 2404
Barrel PixelBarrel Pixelr = 4.4, 7.3, and 10.2 cm11520 readout chips, 48 Mpixels
Forward PixelForward Pixelz = +/-34.5, and +/-46.5 cm4320 readout chips, 18 Mpixels
http://www.hep.vanderbilt.edu/
8 July 2013 Gabella CMS Status 16
CMS - Short TimelineCMS - Short TimelineMarch 2010 --- Started taking data on collisions at 7 TeV. Previous testing done at 0.45 TeV (injection energy) and 1.26 TeV. Low luminosity (intensity)
2010 - 2011 --- Taking data with increasing luminosity (intensity) by both more proton bunches in the rings and more protons in each bunch2012 --- Running at 8 TeV, and high luminosity
July 4, 2012 --- Announce discovery of Higgs-like particle, also seen with the ATLAS detector
March 2013 --- Shutdown LHC and detectors for “Long Shutdown 1,” aka LS1. LHC back “on” in 2015 with energy 14 TeV.
8 July 2013 Gabella CMS Status 17
CMS Recent Results - HiggsCMS Recent Results - HiggsJuly 4, 2012 --- CMS and ATLAS report “Higgs-like particle” at 125 GeV. Too many H->Gamma Gamma events compared to the Standard Model predictions for the Higgs.
July 4, 2013 --- The Higgs looks a lot like the Standard Model (SM) Higgs. Right ratio of different events, better statistics. Mass 125.8 GeV +/- 0.5 GeV Now measuring the quantum numbers of the Higgs: consistent with spin 0 (at least not spin 1 nor spin 2); parity consistent with +1
8 July 2013 Gabella CMS Status 18
8 July 2013 Gabella CMS Status 19
Higgs decays into...Higgs decays into...
8 July 2013 Gabella CMS Status 20
Higgs to two Z's to Four LeptonsHiggs to two Z's to Four Leptons
borrowing from Higgs Seminar
8 July 2013 Gabella CMS Status 21
Note the numbers...Black dots are data.
8 July 2013 Gabella CMS Status 22
CMS (Some) Other Important ResultsCMS (Some) Other Important Results● Supersymmetry
– Looking for “missing energy,” i.e. invisible particles, at least to the detector, as are neutrinos.
– Currently appears to have eliminated many popular SUSY models; we are left with the 105 parameter full-model (maybe).
● Extra-dimensions– Inspired by Super-strings, Randall and Sundrum
took the idea of extra-dimensions (spatial) seriously and asked what would accelerators see/measure.
– No discovery, putting limits on the models.
8 July 2013 Gabella CMS Status 23
CMS Heavy Ion CollisionsCMS Heavy Ion Collisions● LHC Collides Pb-208 ions, fully-stripped to +82 charge
– in other words, atomic number Z=82, atomic mass A=208, number of neutrons N=126
● For protons we inject at 450 GeV and ramp up to 3.5 TeV● Acceleration is by electric field, so a charged particle with
charge Ze would be injected at 450 Z GeV and ramp to 3.5 Z TeV total energy.
– The bending magnets determine what energy (really momentum!) that you can have in your ring of radius rho.
8 July 2013 Gabella CMS Status 24
CMS Heavy Ion CollisionsCMS Heavy Ion Collisions
p on p 3.5 + 3.5 TeV Pb on Pb 287 + 287 TeV 1.38 + 1.38 TeV
7 TeV c.o.m. 2.76 TeV/u
p on p 4 + 4 TeV Pb on Pb 328 + 328 TeV 1.577 + 1.577 TeV
8 TeV c.o.m. 3.15 TeV/u (??)
p on Pb 4 + 328 TeV
4 + 1.577 TeV/u just nucleons
5.02 TeV c.o.m. boosted! not at rest!
8 July 2013 Gabella CMS Status 25
Pb-208 accounts for 52.4% of all stable lead.Z=82, N=126, A=208
CMS Heavy Ions, some numbersCMS Heavy Ions, some numbers
8 July 2013 Gabella CMS Status 26
CMS Heavy Ions - A tutorialCMS Heavy Ions - A tutorial
well centered or glancingblow = Centrality
8 July 2013 Gabella CMS Status 27
CMS Heavy Ions - Make a lot of Particles!CMS Heavy Ions - Make a lot of Particles!
8 July 2013 Gabella CMS Status 28
CMS Heavy Ions - Jet QuenchingCMS Heavy Ions - Jet Quenching
In a head-on collision, more Jets (q-qbar hadron shower) near theedge of the fireball.
Main Jet - not modified
Away Jet - highly modifiedBorrowed from Iancu fig 42.
8 July 2013 Gabella CMS Status 29
CMS Heavy Ions - Jet QuenchingCMS Heavy Ions - Jet Quenching
Main Jet - not modified
Away Jet - highly modified
8 July 2013 Gabella CMS Status 30
LHC and CMS PlansLHC and CMS Plans
Currently the LHC and all the experiments are doing maintenance.
Expect to start turning on the LHC in 2015, with data taking my mid-year.
8 July 2013 Gabella CMS Status 31
LHC and CMS PlansLHC and CMS Plans
8 July 2013 Gabella CMS Status 32
BackupBackup
8 July 2013 Gabella CMS Status 33
Some Links/ReferencesSome Links/References
● http://www.particleadventure.org
● Vanderbilt HEP Group http://www.hep.vanderbilt.edu/~focuser/index.php
● CMS Public Talks http://cms.web.cern.ch/org/cms-presentations-public
● CMS News http://cms.web.cern.ch
The Standard Model of Particle Physics
LHC and Heavy Ions● Ions Page
http://lhc-commissioning.web.cern.ch/lhc-commissioning/commissioning-ions.htm http://lhc-commissioning.web.cern/lhc-commissioning/commissioning-ions.htm
● LHC consolidationshttp://home.web.cern.ch/about/accelerators/large-hadron-collider http://home.web.cern.ch/about/updates/2013/03/lhc-consolidations-step-step-guide
8 July 2013 Gabella CMS Status 34
BackupBackup
8 July 2013 Gabella CMS Status 35
Units? 1 eV...Units? 1 eV...
8 July 2013 Gabella CMS Status 36
8 July 2013 Gabella CMS Status 37
LHC Ions, the Numbers 1/4LHC Ions, the Numbers 1/4
● LHC Collides Pb-208 ions, fully-stripped to +82 charge
– in other words, atomic number Z=82, atomic mass A=208
● For protons we inject at 450 GeV and ramp up to 3.5 TeV● Acceleration is by electric field, so a charged particle with
charge Ze could be injected at 450 Z GeV and ramp to 3.5 Z TeV.
– The bending magnets determine what energy (really momentum!) that you can have in your ring.
8 July 2013 Gabella CMS Status 38
LHC Ions, the Numbers 2/4LHC Ions, the Numbers 2/4● A magnetic field B bends a charged particle with
momentum P in an arc of radius .
– Magnet folks like the constant "magnetic rigidity"
– For the LHC ring (and the other injector rings), the B is set by power supplies and magnets and the rho by the vacuum pipe
8 July 2013 Gabella CMS Status 39
LHC Ions, the Numbers 3/4LHC Ions, the Numbers 3/4– So you will see people post that we are injecting at
450 Z GeV and ramping to 3.5 Z TeV for each Pb nucleus (which is a lot, 36.9 TeV injection and ramp to 287 TeV)
– Okay for the physics what is more interesting is the per proton/neutron energy, so per nucleon the numbers are less450 Z/A GeV and ramp to 3.5 Z/A TeV
– Z/A is the average charge per nucleon, 0.4 e, and finally, inject at 177 GeV/u ramp to 1.38 TeV/u, and collide at 2.76 TeV/u.
8 July 2013 Gabella CMS Status 40
LHC Ions, the Numbers 4/4LHC Ions, the Numbers 4/4
● Bunch populations, from recent posting,
– per bunch charge of 1-1.2e10 ... e's– Count the Pb ions at +82e each, find there are
12-14e7 Pb ions per bunch (below you will see that 7e7 is the design)
8 July 2013 Gabella CMS Status 41
LHC Ions Injection ChainLHC Ions Injection Chain
8 July 2013 Gabella CMS Status 42
Pixel NumerologyPixel Numerology
● Barrel has 11520 ROCs, 48 MPxl● Forward has 4320 ROCs, 18 MPxl● 1 ROC has 4160 pixels● Si Sensor pixel size is 100 microns by 150 microns● Fpix has 3 plaquette and 4 plaquette config to its panels: 3
plaquette: 2x5 + 2x4 + 2x3 (ROCs), and the 4 plaquette: 1x5 + 2x4 + 2x3 + 1x2 (ROCs)
● Urs shows fpix: (3x24+3x21)/4320 = 2.6% and bpix (3x16+6x8+3)/1152 = 0.9% not working.
8 July 2013 Gabella CMS Status 43
LHC Ions Physics "Trivia"LHC Ions Physics "Trivia"● Luminosity is limited by the Electron Capture by Pair
Production (ECPP) at the IPs. That is, the e- from an e+e- pair produced in the collision is captured by an Pb ion and that ion is lost on collimators leading to a vacuum problem! Limit is 0.5-1e27 cm^-2 s^-1.
● Original choice was Pb+53 after the first foil into LEAR. It was found that it had an unexpected short lifetime in the electron cooler, it picked up an e- in a much shorter time than either Pb+52 or +54. Chose +54 state. Pb+53 ends with a 5p^5 orbital---that looks bad!While Pb+52 ends with 5p^4 (all paired) and +54 ends with 5p^6.
● Beam Loss Induced Vacuum degradation in LEAR, and the creation of other charge states by Pb+54 interacting with the beam gas, led to a vacuum spec in LEAR of 1e-12 mbar (LHC can be 1e-9mbar).
8 July 2013 Gabella CMS Status 44
The Standard Model - The Tee ShirtThe Standard Model - The Tee Shirt
8 July 2013 Gabella CMS Status 45
The Standard Model - The DetailsThe Standard Model - The DetailsA pretty equation for the Lagrangian Density of the quantum fields...
Photons, W's, Z's bosons, gluons
Electrons, Quarks, Neutrinos
Higgs Particle/Field
Higgs “coupled” to leptons
8 July 2013 Gabella CMS Status 46
“ In its most explicit form, the Lagranian density of the minimal Standard Modelis given by the somewhat uninspiring expression:” A. Connes & M. Marcolli
gluonsphotons
W's and Z's
8 July 2013 Gabella CMS Status 47
Higgs Particle/Field
8 July 2013 Gabella CMS Status 48
...there is more...
electrons
up quarks
The Standard Model - The DetailsThe Standard Model - The Details
8 July 2013 Gabella CMS Status 49
CMS DetectorCMS Detector“ In its most explicit form, the Lagranian density of the minimal Standard Modelis given by the somewhat uninspiring expression:” A. Connes & M. Marcolli
Electromagnetic Fields, W's, Z's bosons
Electrons, Quarks, Neutrinos
Higgs Particle/Field
8 July 2013 Gabella CMS Status 50
An Event: Higgs to 4 muonsAn Event: Higgs to 4 muons
http://www.uscms.org/public_2/about/cms_detector/index.shtml
8 July 2013 Gabella CMS Status 51
An Event: Higgs to 4 muonsAn Event: Higgs to 4 muons