gerber colloq UICtop feb2002

Information about gerber colloq UICtop feb2002

Published on October 15, 2007

Author: Belly

Source: authorstream.com

Content

The Top Quark:  The Top Quark Cecilia E. Gerber UIC Feb 20, 2002 What is the World Made of?:  What is the World Made of? Anaximenes of Miletus (6BC) ELEMENTARY CONSTITUENTS Water Fire Earth Air INTERACTIONS “All forms of Matter are obtained from rarifying Air” Simple: few constituents and interactions. Wrong: No experimental confirmation. What is the World Made of?:  What is the World Made of? Standard Model (~1970 AC) ELEMENTARY CONSTITUENTS INTERACTIONS Electromagnetic 10-2 Strong 1 Weak 10-6 H Higgs Gravity 10-40 Worldwide discoveries that led to the Standard Model:  Worldwide discoveries that led to the Standard Model up/down 1968 SLAC 1990 Nobel Prize strange 1964 BNL 1980 Nobel Prize charm 1974 SLAC/BNL 1976 Nobel Prize bottom 1977 Fermilab Top 1995 D0/CDF Photon 1905 Planck/Einstein 1918/1921 Nobel Prizes Gluon 1979 DESY W/Z 1983 CERN 1984 Nobel Prize QUARKS Force Carriers Worldwide discoveries that led to the Standard Model (cont.):  Worldwide discoveries that led to the Standard Model (cont.) The Fermilab Tevatron Accelerator:  The Fermilab Tevatron Accelerator 1992-96 Run 1: 100pb-1, 1.8TeV 2001-2007(?) Run 2: ~15fb-1, 1.96TeV Next in line: CERN LHC ~2007 (pp) 14TeV p anti-p collider: How do we produce particles?:  How do we produce particles? Accelerate and collide (anti)protons: the collision takes place between the constituents: Proton-anti Proton Collision:  Proton-anti Proton Collision Small x, products boosted along beam direction Large x, can create massive objects that decay to secondaries with large momentum component transverse to the beam For every proton there is a the probability that a single quark (or gluon) carries a fraction “x” of the proton momentum Good way of telling that a hard collision occurred. A generic HEP detector:  A generic HEP detector The D0 and CDF detectors at Fermilab:  The D0 and CDF detectors at Fermilab Slide12:  D0 Detector Top physics at the Tevatron collider:  Top physics at the Tevatron collider Top spin polarization Cross section Production kinematics Top-antitop resonance states Top mass Physics beyond SM? Top quarks are not yet well understood:  Top quarks are not yet well understood Discovered in 1995 by D0 and CDF at Fermilab Run 1 (1992-1996) Integrated Luminosity ~120pb-1 <100 t-tbar events per experiment Everything we know about the top comes from these events! Cross Section = 5.9+-1.7 pb (D0, PRL79,1203,1997) Mass = 174.3+-5.1 GeV (D0/CDF, Fermilab-TM-2084) Run 2 started March 1, 2001. Expect to double the Run 1 data set by the end of the year. Top quark production at hadron colliders:  Top quark production at hadron colliders Top anti-Top pair production (via strong interaction) Run1(1.8TeV) Run2(2TeV) LHC(14TeV) 90% 85% 5% 10% 15% 95% 5 7 800 x-sec(pb) Top quark production at hadron colliders:  Top quark production at hadron colliders (Drell-Yan) (W-gluon fusion) Single Top production (not observed yet) Run1(1.8TeV) Run2(2TEV) LHC(14TeV) 0.7 0.9 10 1.7 2.4 250 x-sec(pb) Importance of studying the Top quark:  Importance of studying the Top quark Measurement of (tt) test of QCD predictions any discrepancy indicates possible new physics Measurement of top mass fundamental parameter of the SM (SM predicts all top properties given its mass) Affects predictions of the SM via radiative corrections (measuring top and W mass constrains the mass of the Higgs Boson) Constraining the Higgs Mass:  Constraining the Higgs Mass Top quark events are rare!:  Top quark events are rare! Top production is a rare process, in Run 1 one collision in every 3109 produced a top-anti top quark pair. Small cross sections require high luminosity, and the ability to detect and filter out t t-bar events from a large number of other processes (backgrounds) Event Selection:  Event Selection ~100% of the time, a top quark decays into a bottom quark and a W boson. A W boson can decay into two quarks or into a charged lepton and a neutrino. So, an event in which top quarks are produced should have either: 6 quarks 4 quarks, a charged lepton and a neutrino 2 quarks, 2 charged leptons and 2 neutrinos In all cases, 2 of the jets originate from b-quarks Top-quark decay:  Top-quark decay Standard Model: For m t>mW+m b Expect tWb to dominate The quarks of the fist two generations (u,d,s,c) appear as a shower of particles called a JET, and cannot be separated from each other. Identifying electrons:  Identifying electrons Identifying electrons:  Identifying electrons Identifying Muons:  Identifying Muons Identifying Muons:  Identifying Muons Identifying Neutrinos:  Identifying Neutrinos Neutrinos do not interact with the detector We infer the presence of a neutrino from the imbalance in the transverse momentum Identifying Neutrinos:  Identifying Neutrinos Identifying Quarks:  Identifying Quarks Quarks (and Gluons) do not exist as free particles. q q-bar pairs are pulled from the vacuum to produce stable particles : mesons, baryons Quarks ``hadronize’’ single quark appears as a ``jet’’ (spray) of hadrons in the detector Identifying Quarks:  Identifying Quarks Identifying b-quarks:  Identifying b-quarks Semileptonic decays of the b-quark example: B(b  + X)  20%  detect muons in jets 1 Identifying b-quarks:  Identifying b-quarks precise tracking close to primary collision point silicon microstrip detectors life time  1.5 ps  c  0.5 mm (short, but not too short) 2 Slide33:  Identifying b-jets Top challenges :  Top challenges Different processes can create top-like collisions. We call these “background” processes. We work hard on identifying the unique features of top which will separate it from background. Our detector and event selection are not perfect. We need to estimate how many Top events do not make it into our samples We optimize event selection for high signal efficiency. Need to solve ambiguities – Statistically sophisticated methods Neutrinos show up as missing energy. If there are 2 in one event, they cannot be disentangled. We do not know which jet comes from which quark Quarks emit gluons, which give rise to extra jets in the events. t t-bar Cross Section – Run 1:  t t-bar Cross Section – Run 1 Dilepton (ee, em, mm ) + 2 Jets + Met Lepton (e, m ) + 3 or 4 Jets + Met All Jets (5 or 6 Jets, b-tag, NN) Cross Sections:  Cross Sections D: PRL 79 1203 (1997); CDF: PRL 80 2773 (1998)(+updates) Top Quark Mass:  Top Quark Mass lepton+jets channel: 1 unknown (pzn) 3 constraints m(ln) = m(qq) = mW m(lnb) = m(qqb) 2-constraint kinematic fit compare to MC to measure mt Gluon radiation can add extra jets up to 24-fold combinatoric ambiguity there are 12 possible assignments of the 4 jets to the 4 quarks (bbqq) - only 6 if one of the jets is b-tagged - only 2 for events with double b-tagged jets The Basic Procedure:  The Basic Procedure In a sample of t t-bar candidates, for each event make a measurement of X = f(mt), where X is a suitably selected estimator for the top mass, e.g. result of the kinematic fit From MC determine shape of X as a function of mt. Determine shape of X for background (MC & data). Add these together and compare with data Top Quark Mass:  Top Quark Mass Run 1Top Mass Summary:  Run 1Top Mass Summary Run 2A Prospects: number of events:  Run 2A Prospects: number of events Run 2A (2001-2004) Integrated Luminosity ~ 2fb-1 Run 2B (2004-2007?) Integrated Luminosity ~ 15fb-1 Run 2A Prospects: Cross Section:  Run 2A Prospects: Cross Section Precision on top cross section ~8% Statistical Error : 4% Systematic errors assumed to scale with statistics errors from backgrounds: decrease with increased statistics of control samples (2%) jet energy scale (2%) Radiation : Initial state (2%), Final state (1%) Limiting Factors ? error on geometric and kinematic acceptances depend on differences between generators (Pythia, Herwig, Isajet) (4%) luminosity error (4%) Run2A Prospects: Mass:  Run2A Prospects: Mass Total uncertainty  2-3 GeV (per experiment) W mass uncertainty  40 MeV  constrain Higgs mass to 80% Accelerator Performance Run2A:  Accelerator Performance Run2A Accelerator: long list of problems to improve luminosity  Run 2a (~2fb-1) will take through 2004. Future Top physics and beyond:  Future Top physics and beyond We have gone a long way, but many questions still have to be addressed: do we understand the properties of top? its mass ? is there a Higgs particle? is this a good theory to explain all fundamental particles masses? 2 Strategies: Look Harder Precision Get a Bigger Hammer Energy The Tevatron is well suited to both of these strategies. The next 5 years will hopefully lead to findings which may change the course of particle physics….  For More Information:  For More Information http://www.fnal.gov/pub/inquiring/index.html http://particleadventure.org Fermilab inquiring minds page LBL page on Particle Physics

Related presentations


Other presentations created by Belly

Capital budgeting
28. 04. 2008
0 views

Capital budgeting

Nice pics slides
17. 09. 2007
0 views

Nice pics slides

perceptron 2 4 2008
30. 04. 2008
0 views

perceptron 2 4 2008

pham07
18. 04. 2008
0 views

pham07

FC STONE GREAT WALL1
17. 04. 2008
0 views

FC STONE GREAT WALL1

Sauter Nuts Bolt ETFs
16. 04. 2008
0 views

Sauter Nuts Bolt ETFs

UnivOfGuelphNov26th
14. 04. 2008
0 views

UnivOfGuelphNov26th

fujiwara
13. 04. 2008
0 views

fujiwara

Week 08 Finance
10. 04. 2008
0 views

Week 08 Finance

Lct1
09. 04. 2008
0 views

Lct1

outlook
19. 06. 2007
0 views

outlook

Microsoft Windows Vista
19. 06. 2007
0 views

Microsoft Windows Vista

2004 presentation
13. 09. 2007
0 views

2004 presentation

Australian
13. 09. 2007
0 views

Australian

NBB
13. 09. 2007
0 views

NBB

Thilo Ewald ppt
13. 09. 2007
0 views

Thilo Ewald ppt

20031216 NASANIH presentation
05. 10. 2007
0 views

20031216 NASANIH presentation

mna presentation
17. 10. 2007
0 views

mna presentation

lect29 groupwords
18. 10. 2007
0 views

lect29 groupwords

Essential Q Imperialism 2
22. 10. 2007
0 views

Essential Q Imperialism 2

p puska
07. 09. 2007
0 views

p puska

Productivity
07. 09. 2007
0 views

Productivity

honeyPots
13. 09. 2007
0 views

honeyPots

NDB Bensouda
23. 10. 2007
0 views

NDB Bensouda

181105
24. 10. 2007
0 views

181105

METO200Lect19 20
05. 10. 2007
0 views

METO200Lect19 20

oksupercompsymp2006 talk matrow
17. 10. 2007
0 views

oksupercompsymp2006 talk matrow

mareyes
25. 10. 2007
0 views

mareyes

2 01 3
29. 10. 2007
0 views

2 01 3

Online Class Evaluations 8
30. 10. 2007
0 views

Online Class Evaluations 8

1 3Grand father Journey
02. 11. 2007
0 views

1 3Grand father Journey

TuijaKuisma
07. 09. 2007
0 views

TuijaKuisma

Metallsektor
14. 11. 2007
0 views

Metallsektor

insects in out
13. 09. 2007
0 views

insects in out

oasen
16. 11. 2007
0 views

oasen

Unit 10 Scent Theory
17. 11. 2007
0 views

Unit 10 Scent Theory

SPEAR 2004
21. 11. 2007
0 views

SPEAR 2004

danse macabre
22. 11. 2007
0 views

danse macabre

kmutt
13. 09. 2007
0 views

kmutt

NCUR SDT 4 19 05
04. 01. 2008
0 views

NCUR SDT 4 19 05

Lioi Altered Version
07. 01. 2008
0 views

Lioi Altered Version

Five Halloween Pumpkins audacity
02. 11. 2007
0 views

Five Halloween Pumpkins audacity

smime
07. 10. 2007
0 views

smime

CdF BEC
20. 11. 2007
0 views

CdF BEC

WEB C Schumacher
23. 10. 2007
0 views

WEB C Schumacher

bsb
13. 09. 2007
0 views

bsb

2006052213550876705
03. 01. 2008
0 views

2006052213550876705

1 11
19. 02. 2008
0 views

1 11

Ukraine
20. 02. 2008
0 views

Ukraine

truck tmp1002
27. 02. 2008
0 views

truck tmp1002

ace program plan
29. 02. 2008
0 views

ace program plan

takala
07. 09. 2007
0 views

takala

464 TM12
14. 12. 2007
0 views

464 TM12

ICEBP presentation for ANZCP A
10. 03. 2008
0 views

ICEBP presentation for ANZCP A

aionescu cmc dec06
30. 10. 2007
0 views

aionescu cmc dec06

creationtalk
11. 03. 2008
0 views

creationtalk

Data Mining 2
12. 03. 2008
0 views

Data Mining 2

Omaha Pres for NAP web2
29. 12. 2007
0 views

Omaha Pres for NAP web2

sustainable development part1
26. 03. 2008
0 views

sustainable development part1

Schrage
31. 08. 2007
0 views

Schrage

IHYJP Kickoff Poster
09. 10. 2007
0 views

IHYJP Kickoff Poster

020703 DHCAL
31. 08. 2007
0 views

020703 DHCAL

Vimpel Com
31. 08. 2007
0 views

Vimpel Com

Overland vista uib itforum
19. 06. 2007
0 views

Overland vista uib itforum

OS Notes
19. 06. 2007
0 views

OS Notes

NVIDIA OpenGL on Vista
19. 06. 2007
0 views

NVIDIA OpenGL on Vista

NonAdmin Pilot
19. 06. 2007
0 views

NonAdmin Pilot

New Mexico NETUG WPF
19. 06. 2007
0 views

New Mexico NETUG WPF

nercomp SIG
19. 06. 2007
0 views

nercomp SIG

MSAM Launch Vista Final Updated
19. 06. 2007
0 views

MSAM Launch Vista Final Updated

MOSS WF Talk
19. 06. 2007
0 views

MOSS WF Talk

More Online Games
19. 06. 2007
0 views

More Online Games

MHay Wireless
19. 06. 2007
0 views

MHay Wireless

Marl WSUS3
19. 06. 2007
0 views

Marl WSUS3

mail list news
19. 06. 2007
0 views

mail list news

Lenovo UofU
19. 06. 2007
0 views

Lenovo UofU

Lecture II
19. 06. 2007
0 views

Lecture II

Smith F09
13. 10. 2007
0 views

Smith F09

35508
26. 02. 2008
0 views

35508

pinar
19. 06. 2007
0 views

pinar

pgp
19. 06. 2007
0 views

pgp

pessner
19. 06. 2007
0 views

pessner

Overview Presentation
19. 06. 2007
0 views

Overview Presentation

North Dakota Annuity Deck
19. 06. 2007
0 views

North Dakota Annuity Deck

Rutland Presentation plenary4
31. 08. 2007
0 views

Rutland Presentation plenary4

NAMI NC 112707
07. 01. 2008
0 views

NAMI NC 112707

finland poster
07. 09. 2007
0 views

finland poster

sample
27. 09. 2007
0 views

sample

dtk
13. 09. 2007
0 views

dtk

Phenotyping Oxford
17. 10. 2007
0 views

Phenotyping Oxford

dog breeding
19. 11. 2007
0 views

dog breeding

5th trondhiem
29. 11. 2007
0 views

5th trondhiem

policies regs
28. 12. 2007
0 views

policies regs

GetuHailu
13. 09. 2007
0 views

GetuHailu

genealogy
01. 10. 2007
0 views

genealogy

net info 050928
19. 06. 2007
0 views

net info 050928

chap7
15. 10. 2007
0 views

chap7

Rafael Guillen CCAD SIAM mar06
22. 10. 2007
0 views

Rafael Guillen CCAD SIAM mar06

na3 Russia
31. 08. 2007
0 views

na3 Russia

Sois Global Programs3 12 04
31. 08. 2007
0 views

Sois Global Programs3 12 04

sacha
31. 08. 2007
0 views

sacha

amm pres valdez lacnic
22. 10. 2007
0 views

amm pres valdez lacnic

nwnt
19. 06. 2007
0 views

nwnt

STAR shielding 2
13. 11. 2007
0 views

STAR shielding 2

voiceline overview
17. 10. 2007
0 views

voiceline overview

gross PPT
07. 04. 2008
0 views

gross PPT

WP1a
15. 10. 2007
0 views

WP1a

Microarray Data Standard
07. 11. 2007
0 views

Microarray Data Standard

Lim Badejo Dell Presentation 1
19. 06. 2007
0 views

Lim Badejo Dell Presentation 1

HongKong Punkka Salo
07. 09. 2007
0 views

HongKong Punkka Salo

Dvoretsky
31. 08. 2007
0 views

Dvoretsky

qm1 web
03. 01. 2008
0 views

qm1 web

IAPS
07. 09. 2007
0 views

IAPS

yalestudy
28. 09. 2007
0 views

yalestudy

digvlsideslec1
12. 10. 2007
0 views

digvlsideslec1

mead
13. 09. 2007
0 views

mead

bashmakov
31. 08. 2007
0 views

bashmakov