The Standard Model: Current Status & Open Questions

Chris Quigg Fermilab Tentative Outline

1 Why Hadron Colliders? What Is a Proton? 2 Constructing the Electroweak Theory 3 Validating the Electroweak Theory 4 The Higgs Boson and Beyond 1

The Standard Model: Current Status & Open Questions

Chris Quigg Fermilab Our Conception of Matter—the Nanoworld

If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis that all things are made of atoms — little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied.

— R. P. Feynman, The Feynman Lectures on Physics

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 1 / 158 · Our Conception of Matter—the Nanonanoworld

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 2 / 158 · Our Conception of Matter—the Attoworld

18 Pointlike constituents (r < 10− m) u c t d s b  L  L  L

νe νµ ντ e− µ− τ −  L  L  L

Few fundamental forces, derived from gauge symmetries

SU(3) SU(2) U(1) c ⊗ L ⊗ Y Electroweak symmetry breaking: Higgs mechanism?

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 3 / 158 · Problem 1 In the spirit of Feynman’s characterization of the atomic hypothesis, compose a sentence that expresses the “enormous amount of information about the world” captured in the standard model of particle physics, “if just a little imagination and thinking are applied.”

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 4 / 158 · Why Hadron Colliders? ; Eric Prebys Lectures

Discovery machines

0 W ±, Z , t, H,...

Precision instruments

MW , mt, Bs oscillation frequency, . . .

Large energy reach High event rate ·

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 5 / 158 · Why Hadron Colliders?

Explore a rich diversity of elementary processes at the highest accessible energies:

(qi , q¯i , g, γ, W ±, Z,...) (qj , q¯j , g, γ, W ±, Z,...) ⊗

Example: quark-quark collisions at √s = 1 TeV

If 3 quarks share half the proton’s momentum ( x = 1), h i 6 require pp collisions at √s = 6 TeV

; Fixed-target machine with beam momentum p 2 104 TeV = 2 1016 eV (cf. cosmic rays). ≈ × ×

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 6 / 158 · ANRV391-NS59-15 ARI 16 September 2009 15:36

Cosmic-ray Spectrum 105

10 2

10–1

10–4

10–7

Knee

–1 10–10 sr s Gev) 2 10–13 Flux (m

10–16

Ankle

10–19 LEAP Proton 10–22 AKENO KASCADE Auger SD Auger hybrid 10–25 AGASA HiRes-I monocular by Universidade Estadual de Campinas (Unicamp) on 07/20/14. For personal use only.

Annu. Rev. Nucl. Part. Sci. 2009.59:319-345. Downloaded from www.annualreviews.org HiRes-II monocular

10–28

109 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 Energy (eV)

Figure 1 Chris Quigg (FNAL)Overview of the cosmic ray spectrum.The Approximate Standard energies Model of the breaks . . . in the spectrum commonlyFermilab 11–14.8.2014 7 / 158 referred to as the knee and the ankle are indicated by arrows. Data are from LEAP (4), Proton (5), AKENO · (6), KASCADE (7), Auger surface detector (SD) (8), Auger hybrid (9), AGASA (10), HiRes-I monocular (11), and HiRes-II monocular (11). Scaling of LEAP proton-only data to the all-particle spectrum follows (12).

www.annualreviews.org • The Highest-Energy Cosmic Rays 321 Cosmic-ray Spectrum

Knee 104

] Grigorov -1 JACEE sr

-1 MGU 3 s 10 Tien-Shan -2 Tibet07 Ankle

m Akeno 1.6 CASA-MIA 102 HEGRA Fly’s Eye [GeV Kascade Kascade Grande 2011 F(E) AGASA 2.6 10 HiRes 1 E HiRes 2 Telescope Array 2011 Auger 2011 1 1013 1014 1015 1016 1017 1018 1019 1020 E [eV]

dI 16 16 2 1 1 1 (2 10 eV) = (3 - 5) 10− m− s− sr− eV− dE × ×

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 8 / 158 · Pierre Auger Observatory Public Event Explorer

Pierre Auger Observatory PierreSize Auger of the Observatory Pierre Auger overObservatory Fermilab Public Event Explorer

Event Selection Min Max

Nb. of stations 5

Zenith Angle 0 60

Energy (EeV) 15

Order Id / Date (reverse) Show 10 Events Search

Go to event Id 4128900

Size of the Pierre Auger Observatory

Imagery ©2014Report TerraMetrics a map error Space Weather page Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 9 / 158 See Auger superimposed over Fermilab GO ·

Recenter Auger in the current view.

| FAQ | About

Page hosted by the Auger group at Colorado State University Some Great Cosmic-Ray Observatories

19 2 1 E > 10 eV: 1 km− century−

Pierre Auger Observatory (Mendoza, Argentina): 3000 km2 array of 1600 shower detectors plus 4 ∼ atmospheric fluorescence detectors

Telescope Array (Utah, USA): 750 km2 array of 500 scintillation detectors plus 3 atmospheric∼ fluorescence telescopes

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 10 / 158 · Problem 2 Plot the correspondence between c.m. energy, √s, and fixed-target beam momentum, plab, for pp collisions over the range 10 GeV √s 100 TeV. Note in particular ≤ ≤ the values of plab that correspond to √s = 8, 14, 100 TeV.

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 11 / 158 · How to achieve? Fixed-target, p 2 104 TeV ≈ × Ring radius is 10 p B r = km. 3 · 1 TeV 1 tesla   .   Conventional copper magnets (B = 2 teslas) ;

r 1 105 km. ≈ 3 × 1 size of Moon’s orbit ≈ 12 10-tesla field reduces the accelerator to mere Earth size (R = 6.4 103 km). ⊕ ×

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 12 / 158 · Fermi’s Dream Machine (1954) 5000-TeV protons to reach √s 3 TeV ≈ 2-tesla magnets at radius 8000 km

Projected operation 1994, cost $170 billion (inflation assumptions not preserved)

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 13 / 158 · Key Advances in Accelerator Technology Alternating-gradient (“strong”) focusing, invented by Christofilos, Courant, Livingston, and Snyder. Before and After ...

Synchrotron Beam Tube Magnet Size Bevatron (6.2 GeV) 1 ft 4 ft 9 1 ft 20 1 ft × 2 × 2 FNAL Main Ring (400 GeV) 2 in 4 in 14 in 25 in ∼ × × LHC ( 7 TeV) 56 mm (SC) → The idea of colliding beams. Superconducting accelerator magnets based on “type-II” superconductors, including NbTi and Nb3Sn.

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 14 / 158 · Key Advances . . .

Active optics to achieve real-time corrections of the orbits makes possible reliable, highly tuned accelerators using small-aperture magnets. Also “cooling,” or phase-space compaction, of stored (anti)protons. The evolution of vacuum technology. Beams stored for approximately 20 hours travel 2 1010 km, ∼ × about 150 times the Earth–Sun distance, without encountering a stray air molecule. The development of large-scale cryogenic technology, to maintain many km of magnets at a few kelvins.

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 15 / 158 · Hadron Colliders through the Ages CERN Intersecting Storage Rings: pp collider at √s 63 GeV. Two rings of conventional magnets. → S¯ppS Collider at CERN:pp ¯ collisions at √s = 630( 900) GeV in conventional-magnet SPS. → Fermilab Tevatron Collider:pp ¯ collisions at √s 2 TeV with 4-T SC magnets in a 2π-km tunnel. ≈ Brookhaven Relativistic Heavy-Ion Collider: 3.45-T dipoles in 3.8-km tunnel. Polarized pp, √s 0.5 TeV → Large Hadron Collider at CERN: 14-TeV pp collider in the 27-km LEP tunnel, using 9-T magnets at 1.8 K. An Even Bigger Collider? High-energy collider parameters, 2012 Review of Particle Properties 28 Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 16§ / 158 · Tevatron:pp ¯ at √s = 1.96 TeV

CDF CQ D0

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 17 / 158 · Large Hadron Collider at CERN

CMS

LHCb

ALICE ATLAS

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 18 / 158 · Competing technologies?

None for quark–gluon interactions None for highest energies (derate composite protons) Lepton–lepton collisions: LEP (√s 0.2 TeV) was ≈ the last great electron synchrotron? Synchrotron radiation linear colliders for higher √s ⇒ ; International Linear Collider

I Challenge to reach 1 TeV; a great challenge L I Can we surpass 1 TeV? CLIC, . . .

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 19 / 158 · Competing technologies?

Lepton–hadron collisions: HERA (e±p) as example; + energy intermediate between e e−, pp

e±(u, d) leptoquark channel, proton structure, γp High a challenge: beam profiles don’t match L

(Far) future: µ±p collider?

Heavy-ion collisions: RHIC the prototype; LHC (relatively) modest energy per nucleon; quark-gluon plasma; new phases of matter

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 20 / 158 · Unorthodox projectiles?

γγ Collider: Backscattered laser beams; enhancement of linear collider capabilities + µ µ− collider: Advantage of elementary particle, disadvantage of muon decay (2.2µs). Small ring to reach very high effective energies?

Muon storage ring (neutrino factory) would turn bug into feature!

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 21 / 158 · week ending PRL 111, 012001 (2013) PHYSICAL REVIEW LETTERS 5 JULY 2013

TABLE IV. Summary of the measured cross sections with detailed uncertainty composition. The uncertainty follows from the COMPETE preferred-model extrapolation error of 0:007. The right-most column gives the full systematic uncertainty, combined in quadrature and considering the correlations between the contributions.

Systematic uncertainty Quantity Value el. t-dep el. norm inel ) full

tot (mb) 101.7 1:8 1:4 1:9 0:2 )2:9 inel (mb) 74.7 1:2 0:6 0:9 0:1 )1:7 el (mb) 27.1 0:5 0:7 1:0 0:1 )1:4 el=inel (%) 36.2 0:2 0:7 0:9 )1:1 el=tot (%) 26.6 0:1 0:4 0:5 )0:6 extracted and applied as a function of the T2 track multi- and transferring it to the T2 region. The uncertainty takes plicity and affects only the 1h category. The systematic into account the different conditions (average charged uncertainty is estimated to be 0.45% which corresponds multiplicity, pT threshold, gap size, and surrounding to the maximal variation of the background that gives a material) between the two detectors. compatible fraction of 1h events (trigger and pileup cor- Central diffraction: This correction takes into account rected) in the two samples. events with all final state particles outside the T1 and T2 Trigger efficiency: This correction is estimated from the pseudorapidity acceptance and it is determined from simu- zero-bias triggered events. It is extracted and applied as a lations based on the PHOJET and MBR event generators function of the T2 track multiplicity, being significant [15,16]. Since the cross section is unknown and the uncer- for events with only one track and rapidly decreasing to tainties are large, no correction is applied to the inelastic zero for five or more tracks. The systematic uncertainty is rate but an upper limit of 0.25 mb is taken as an additional evaluated comparing the trigger performances with and source of systematic uncertainty. without the requirement of having a track pointing to the Low mass diffraction: The T2 acceptance edge at jj¼ vertex and comparing the overall rate correction in the two 6:5 corresponds approximately to diffractive masses of samples. 3.6 GeV (at 50% efficiency). The contribution of events Pileup: This correction factor is determined from the with all final state particles at jj > 6:5 is estimated with zero-bias triggered events: the probability to have a bunch QGSJET-II-03 after tuning the Monte Carlo prediction with crossing with tracks in T2 is 0.05–0.06 fromp which±p theInteraction Rates probability of having n 2 inelastic collisions with tracks in T2 in the same bunch crossing is derived. The systematic uncertainty is assessed from the variation, within the same data set, of the probability to have a bunch crossing with tracks in T2 and from the uncertainty due to the T2 event reconstruction efficiency. Reconstruction efficiency: This correction is estimated using Monte Carlo generators (PYTHIA8 [13], QGSJET- II-03 [14]) tuned with data to reproduce the measured fraction of 1h events which is equal to 0:216 0:007. The systematic uncertainty is assumed to be half of the correction: as it mainly depends on the fraction of events with only neutral particles in T2, it accounts for variations between the different Monte Carlo generators. T1 only: This correction takes into account the amount of events with no final state particles in T2 but one or FIG. 1 (color). Compilation [8,20–24] of the total (tot), in- more tracks in T1. The uncertainty is the precision with which this correction can be calculated from the zero-bias elastic ( inel) andσtot elastic(101 ( el). cross-section7 2.9) mb measurements: the TOTEM measurements described± in this Letter are highlighted. sample plus the uncertainty of the T1 reconstruction The continuousσ blackinel lines(74 (lower.7 for1pp.7), upper mb for pp ) repre- efficiency. sent the best fits of the total cross-section± data by the COMPETE 11 σel (27.1 1.4) mb Internal gap covering T2: This correction takesσtot into10 collaborationpb [19]. The dashed line± results from a fit of the TOTEM account the events which could have a rapidity gap fully≈ Chris Quiggelastic (FNAL) scattering data. TheThe Standarddash-dotted Model lines . . . refer to theFermilab inelastic11–14.8.2014 22 / 158 covering the T2 range and no tracks in T1. It is estimated cross section and are obtained as the difference between· the from data, measuring the probability of having a gap in T1 continuous and dashed fits.

012001-4 Collider Cross Sections

8 TeV 14 TeV 33 TeV 100 TeV LHC LHC HE LHC VLHC 1012 109 total 1011 108

1010 107

109 106 bb –1 8 5 s

10 10 2

7 4 10 jet 10 cm

jet 33 (pT >50 GeV) 106 103

5 2 [pb] 10 W 10 σ Z 4 1 10 γ 10 γ (pT>50 GeV) 103 gg→H 100 tt 102 t VBF 10-1 WW ttH Events / second @ 10 WZ WH -2 10 ZZ ZH 10 γγ 1 HH 10-3

10-1 10-4 MCFM 10-2 10-5 10 102 s [TeV] Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 23 / 158 · Standard-model Cross Sections 106 103

105 LHC 14 TeV 102 LHC 13 TeV –1

4 LHC 8 TeV 1 s 10 W+ 10 2 Z Tevatron

3 0 cm

10 10 33

102 10–1

–2

[pb] 10 WW 10

σ tt –3 +Z 1 W ZZ t[t] 10 ggH t[s] 10–1 10–4 W+H ZH

10–2 VBF 10–5 Events / second @ 10 t Wt + HH –3 t Ht Z'SSM –6 10 3 TeV 10 MCFM Z'SSM 5 TeV 10–4 10–7 Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 24 / 158 · Standard-modelStandard Model Total Production Cross Cross Sections Section Measurements Status: July 2014

11 10 80 µb 1 − Preliminary [pb] ATLAS Run 1 √s = 7,8TeV σ 106 LHC pp √s = 7TeV LHC pp √s = 8TeV 5 10 1 Theory Theory 35 pb−

1 Data Data 35 pb− 104

103

1 20.3 fb−

1 1 2 4.6 fb− 20.3 fb− 1 10 20.3 fb− 1 1 4.6 fb− 1 1 1 20.3 fb− 4.7 fb− 4.6 fb− 20.3 fb− 1 13.0 fb− 4.6 fb 1 1 1 1 − 20.3 fb 1 10 4.8 fb− 2.0 fb− − 1 1 4.6 fb− 20.3 fb−

1 1 20.3 fb− 1 20.3 fb−

1 10−

pp W Z t¯t tt chan WWZ +W WW H ggF Wt WZ ZZ H VBF Wt¯t tZ¯t − total total total total total total total total total total total total total total

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 25 / 158 · Luminosity Number N of events of interest

N = σ dt (t) L Z 2 1 (t): instantaneous luminosity [in cm− s− ] L

Bunches of n1 and n2 particles collide head-on at frequency f : n n (t) = f 1 2 L 4πσxσy σ : Gaussian rms beam sizes x,y ⊥ Edwards & Syphers, 2012 Review of Particle Physics, 27 LHC lumi calculator Zimmerman, “LHC: The Machine,”§ SSI 2012

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 26 / 158 · LHC Luminosity Growth

1400 1400 bunches cross every 50 ns (25 ns in future?) ⊗

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 27 / 158 · High Luminosity and Pileup

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 28 / 158 · Problem 3 (a) Estimate the integrated luminosity required to make a convincing observation of each of the standard-model final states shown in the ATLAS plot above . Take into account the gauge-boson branching fractions given in the Review of Particle Physics.

(b) Taking a nominal year of operation as 107 s, translate your results into the required average luminosity.

Hard scattering σ 1/ˆs ; ˆs ∝ L ∝

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 29 / 158 · What Is a Proton?

(For hard scattering) a broad-band, unseparated beam of quarks, antiquarks, gluons, & perhaps other constituents, characterized by parton densities (a) 2 fi (xa, Q ), . . . number density of species i with momentum fraction 2 xa of hadron a seen by probe with resolving power Q .

Q2 evolution given by QCD perturbation theory

(a) 2 fi (xa, Q0 ): nonperturbative

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 30 / 158 · Group: 1 Group: 2 Evolution of the Strong Coupling Constant Group: 16 12 Group: 5 Group: 6 Group: 7 11 Group: 8 Group: 9 10 Group: 10 Group: 11 9 Group: 12 Group: 13 8 Group: 14

s Group: 29 α 7 1/ 6

5

4

3

2 100 101 102 103 Q [GeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 31 / 158 · (a) 2 Deeply Inelastic Scattering ; fi (xa, Q0 ) 107 x=0.015 (x40)

–5 10 6 x=6.18•10 10 x=9.5•10–5 x=0.045 (x12) x=2•10–4 x=3.2•10–4 105 x=5•10–4 x=0.08 (x6) x=8•10–4 x=1.3•10–3 x=0.125 (x3.5) 104 x=2•10–3 x=3.2•10–3 x=0.175 (x2) x=5•10–3 x=0.225 (x1.5) 103 x=8•10–3 1 –2 x=0.275 (x1.2)

) x=1.3•10 ) 2 x=2•10–2 2 2 10 x=3.2•10–2 (x,Q x=0.35

(x,Q 3

–2 NC

r x=5•10 xF σ 10 x=8•10–2 x=0.45 x=0.13 x=0.18 1 x=0.55 x=0.25 0.1 x=0.4 10–1 x=0.65 NuTeV CCFR 97 10–2 x=0.65 CDHSW NuTeV fit x=0.75 10–3 10 102 103 104 105 1 10 100 Q2 (GeV2) Q2 (GeV2)

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 32 / 158 · What Is a Proton? MSTW 2008 NLO PDFs (68% C.L.) ) )

2 1.2 2 1.2

Q2 = 10 GeV2 Q2 = 104 GeV2

xf(x,Q 1 xf(x,Q 1 g/10 g/10 0.8 0.8

0.6 u 0.6 b,b u

d 0.4 d 0.4 c,c

c,c s,s 0.2 s,s d 0.2 d u u

0 0 -4 -3 -2 -1 -4 -3 -2 -1 10 10 10 10 1 10 10 10 10 1 x x

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 33 / 158 · Parton Distribution Functions Literature

The state of the art is reviewed in A. De Roeck & R. S. Thorne, Prog. Part. Nucl. Phys. 66, 727 (2011).

Recommendations and assessments of uncertainties are given by the PDF4LHC Working Group.

Convenient access to many sets of parton distributions is available through the Durham HEPData Project Online.

A common interface to many modern sets of PDFs is M. R. Whalley & A. Buckley, “LHAPDF: the Les Houches Accord Parton Distribution Function Interface.”

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 34 / 158 · 1 2 Flavor Content of the Proton: dx x fi (x, Q ) 1 0 g R u

d 10–1 _ d _ u_ s

–2

Momentum fraction 10

c b

10–3 1102 104 106 108 Q2 (GeV2) 2 8 3 Asymptotic limit (Q ): g : 17; qs : 68; qv : 0 Chris Quigg (FNAL) The Standard→ ∞ Model . . . Fermilab 11–14.8.2014 35 / 158 · Hard-scattering cross sections

c

σˆ _ √ i sˆ j

a b

dσ(a + b c + X ) = dxadxb δ(τ xaxb) → − · ij X Z (a) 2 (b) 2 f (xa, Q )f (xb, Q )dσˆ(i + j c + X ), i j →

dσˆ : elementary cross section at energy √ˆs = √xaxbs (τ = ˆs/s)

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 36 / 158 · Example Leading-Order Calculation Compute the differential cross section dσ/dt for the elementary reaction ud ud, neglecting quark masses. → Show that 4πα2 ˆs2 +u ˆ2 dσ(ud ud)/dˆt = s , → 9ˆs2 · ˆt2 where ˆs, ˆt, uˆ are the usual Mandelstam invariants for the parton-parton collision.

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 37 / 158 · Problem 4 (a) Express the ud ud cross section in terms of c.m. angular variables, and note→ that the angular distribution is reminiscent of that 4 for Rutherford scattering, dσ/dΩ∗ 1/ sin (θ∗/2). ∝ (b) In the search for new interactions, the angular distribution for quark-quark scattering, inferred from dijet production in p±p collisions, is a sensitive diagnostic. Show that when re-expressed in terms of the variable χ = (1 + cos θ∗)/(1 cos θ∗), the angular distribution for ud scattering is dσ/dχ −constant. ∝ 1 (c) The rapidity variable, y = 2 ln[(E + pz )/(E pz )], is useful in the study of high-energy collisions because it shifts− simply under Lorentz boosts. Show that in the extreme relativistic limit, measuring the jet rapidities in the reaction p±p jet1 + jet2 leads directly to a determination of the variable χ→for parton-parton scattering as χ = exp(y1 y2). For early LHC studies, see G. Aad et al. [ATLAS Collaboration],− Phys. Lett. B 694, 327 (2011); V. Khachatryan et al. [CMS Collaboration], Phys. Rev. Lett. 106, 201804 (2011).

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 38 / 158 · Probing Elementarity

E : 1.8 TeV + 1.8 TeV Dijet mass: 4 TeV ⊥ ·

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 39 / 158 · Probing Elementarity

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 40 / 158 · FERMILAB–FN–0913–T Rev. February 1, 2011

FERMILAB–FN–0839–T Physics Potential versusAugust 24, Energy 2009

LHC Physics Potential vs. Energy: Considerations for the 2011 Run Chris Quigg* LHC Physics Potential vs. Energy Theoretical Physics Department Fermi National Accelerator Laboratory Chris Quigg* Batavia, Illinois 60510 USA and Theoretical Physics Department CERN, Department of Physics, Theory Unit Fermi National Accelerator Laboratory CH1211 Geneva 23, Switzerland Batavia, Illinois 60510 USA

Parton luminosities are convenient for estimating how the Parton luminosities are convenient for estimating how the physics potential of Large Hadron Collider experiments physics potential of Large Hadron Collider experiments depends on the energy of the proton beams. I quan- depends on the energy of the proton beams. I present tify the advantage of increasing the beam energy from parton luminosities, ratios of parton luminosities, and 3.5 TeV to 4 TeV. I present parton luminosities, ratios contours of fixed parton luminosity for gg, ud¯, and qq of parton luminosities, and contours of fixed parton lumi- interactions over the energy range relevant to the Large nosity for gg, ud¯, qq, and gq interactions over the energy Hadron Collider, along with example analyses for specific range relevant to the Large Hadron Collider, along with processes. arXiv:1101.3201v2 [hep-ph] 1 Feb 2011 example analyses for specific processes. This note ex- tends the analysis presented in Ref. [1]. Full-size figures are available as pdf files at lutece.fnal.gov/PartonLum11/. arXiv:0908.3660v2 [hep-ph] 8 Sep 2009

EHLQ, Rev. Mod. Phys. *E-mail:[email protected], 579 (1984) *E-mail:[email protected] Ellis, Stirling, Webber, QCD & Collider Physics MRSW08NLO examples + RKE Lecture 3, SUSSP 2009 Full-page figures: lutece.fnal.gov/PartonLum11 High-energy p: broadband unseparated beam of q,q ¯, g

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 41 / 158 · Parton Luminosities + Prior Knowledge = Answers Taking into account 1/ˆs behavior of hard scattering,

1 τ d τ/ˆs dx a b a b L [f ( )(x)f ( )(τ/x) + f ( )(x)f ( )(τ/x)] ˆs dτ ≡ 1 + δ x i j j i ij Zτ is a convenient measure of parton ij luminosity.

(a) fi (x): pdf; τ = ˆs/s

1 dτ τ d ij σ(s) = L [ˆsσˆij (ˆs)] τ · ˆs dτ · ij Zτ0 X{ }

EHLQ 2; QCD & Collider Physics, 7.3 § § Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 42 / 158 · Parton Luminosity

CTEQ6L1: gg 106 105 104 103 102 101 0 0.9 TeV 10 2 TeV 10-1 4 TeV 6 TeV 10-2 7 TeV 8 TeV Parton Luminosity [nb] -3 10 10 TeV 10-4 14 TeV 10-5 10-6 10-2 10-1 100 101 [TeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 43 / 158 · Parton Luminosity

— CTEQ6L1: ud 106 105 104 103 102 101 0.9 TeV 2 TeV 0 10 Tevatron -1 4 TeV 10 6 TeV 10-2 7 TeV 8 TeV Parton Luminosity [nb] -3 10 10 TeV 10-4 14 TeV 10-5 10-6 10-2 10-1 100 101 [TeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 44 / 158 · Parton Luminosity (light quarks)

CTEQ6L1: qq 106 105 104 103 102 101 0.9 TeV 0 2 TeV 10 4 TeV 10-1 6 TeV 7 TeV 10-2 8 TeV 10 TeV Parton Luminosity [nb] -3 10 14 TeV 10-4 10-5 10-6 10-2 10-1 100 101 [TeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 45 / 158 · Parton Luminosity (gluon–light quarks)

CTEQ6L1: gq 106 105 104 103 102 101 0.9 TeV 0 2 TeV 10 4 TeV 10-1 6 TeV 7 TeV 10-2 8 TeV 10 TeV Parton Luminosity [nb] -3 10 14 TeV 10-4 10-5 10-6 10-2 10-1 100 101 [TeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 46 / 158 · Luminosity Ratios

CTEQ6L1: gg 100

10-1 R.9 R2 R4 R6 R7

Ratio to 14 TeV Ratio to 14 -2 10 R8 R10

10-3 10-2 10-1 100 101 [TeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 47 / 158 · Luminosity Ratios

— CTEQ6L1: ud 100

10-1

R0.9 R2 RTev R4 Ratio to 14 TeV Ratio to 14 10-2 R6 R7 R8 R10

10-3 10-2 10-1 100 101 [TeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 48 / 158 · Luminosity Ratios

CTEQ6L1: qq 100

10-1

R0.9 R2 R4 R6 Ratio to 14 TeV Ratio to 14 10-2 R7 R8 R10

10-3 10-2 10-1 100 101 [TeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 49 / 158 · Luminosity Ratios

CTEQ6L1: gq 100

10-1

R0.9 R2 R4 R6 Ratio to 14 TeV Ratio to 14 10-2 R7 R8 R10

10-3 10-2 10-1 100 101 [TeV]

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 50 / 158 · Problem 5

(a) Referring to the gg luminosity ratios , estimate the increased yield of H(125) at 14 TeV compared with 8 TeV.

(b) Referring to the ud¯ luminosity ratios , estimate the increased yield of W 0(2 TeV) and W 0(4 TeV) at 14 TeV compared with 8 TeV.

(c) Referring to the qq luminosity ratios , estimate the increased yield of dijets at √ˆs = 2 TeV and √ˆs = 4 TeV at 14 TeV compared with 8 TeV. (d) Compare your estimates with the explicit Standard-model Cross Sections calculated using MCFM.

Chris Quigg (FNAL) The Standard Model . . . Fermilab 11–14.8.2014 51 / 158 ·