Compact Muon Solenoid (CMS) Physics, Status, and Plans Bill Gabella and Med Webster QuarkNet 2013...

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


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.


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...


Ref: http://www.particleadventure.org


Cosmic Ray Cosmic Ray ShowersShowers

Ref: http://www.particleadventure.org

Mostly Protons withhigh energy hittingthe atmosphere...make mostly muonsat Earth.


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

http://www.fnal.gov/

http://www.cern.ch/


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


The Large Hadron ColliderThe Large Hadron Collider


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


CMS DetectorCMS Detector

http://www.uscms.org/public_2/about/cms_detector/index.shtml

Vanderbilt University (Will Johns)

http://www.uscms.org/public_2/about/cms_detector/index.shtm

Gabella CMS Status8 July 2013 14

Particles through a CMS sliceParticles through a CMS slice


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/

http://www.hep.vanderbilt.edu/


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.


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


Higgs decays into...Higgs decays into...


Higgs to two Z's to Four LeptonsHiggs to two Z's to Four Leptons

borrowing from Higgs Seminar


Note the numbers...Black dots are data.


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.


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.


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!


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


CMS Heavy Ions - A tutorialCMS Heavy Ions - A tutorial

well centered or glancingblow = Centrality


CMS Heavy Ions - Make a lot of Particles!CMS Heavy Ions - Make a lot of Particles!


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.


CMS Heavy Ions - Jet QuenchingCMS Heavy Ions - Jet Quenching

Main Jet - not modified

Away Jet - highly modified


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.


LHC and CMS PlansLHC and CMS Plans


BackupBackup


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

http://www.particleadventure.org/

http://www.hep.vanderbilt.edu/~focuser/index.php

http://cms.web.cern.ch/org/cms-presentations-public

http://cms.web.cern.ch/

http://lhc-commissioning.web.cern.ch/lhc-commissioning/commissioning-ions.htm

http://lhc-commissioning.web.cern/lhc-commissioning/commissioning-ions.htm

http://home.web.cern.ch/about/accelerators/large-hadron-collider

http://home.web.cern.ch/about/updates/2013/03/lhc-consolidations-step-step-guide


BackupBackup


Units? 1 eV...Units? 1 eV...


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.


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


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.


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)


LHC Ions Injection ChainLHC Ions Injection Chain


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.


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).


The Standard Model - The Tee ShirtThe Standard Model - The Tee Shirt


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


“ 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


...there is more...

electrons

up quarks

The Standard Model - The DetailsThe Standard Model - The Details


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



An Event: Higgs to 4 muonsAn Event: Higgs to 4 muons

http://www.uscms.org/public_2/about/cms_detector/index.shtml

http://www.uscms.org/public_2/about/cms_detector/index.shtm


An Event: Higgs to 4 muonsAn Event: Higgs to 4 muons

Compact Muon Solenoid (CMS) Physics, Status, and Plans Bill Gabella and Med Webster QuarkNet 2013...

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