Masahiro KuzeTokyo Institute of Technology

PANIC 2017Beijing, 1 Sep. 2017

Energy-frontier lepton-hadron collisions at CERN:

the LHeC and the FCC-ehLHeCDetectorDesign

CDRdesign2012DetectornowincludingFCC-heTrackerandCalorimetersProjectDevelopment–NextSteps

MaxKleinUniversityofLiverpool

fortheLHeCStudyGroup

DevelopmentoftheLHeCDetector,DIS17,Brum,5thofApril2017

Forreferences,pleaseconsultlhec.web.cern.chLHeCCDRarXiv:1206.2913J.Phys.G39(2012)075001

FCC_eh:Ee=60GeVEp=50TeVHELHC:Ep=14TeV

LHeC:Ee=60GeVEp=7TeV

LHeCDetectorDesign

CDRdesign2012DetectornowincludingFCC-heTrackerandCalorimetersProjectDevelopment–NextSteps

MaxKleinUniversityofLiverpool

fortheLHeCStudyGroup

DevelopmentoftheLHeCDetector,DIS17,Brum,5thofApril2017

Forreferences,pleaseconsultlhec.web.cern.chLHeCCDRarXiv:1206.2913J.Phys.G39(2012)075001

FCC_eh:Ee=60GeVEp=50TeVHELHC:Ep=14TeV

LHeC:Ee=60GeVEp=7TeV

ep collisions: DIS•Traditional and best way to probe the inner structure of nucleons and nuclei•At high energy, electroweak bosons (Z/W) play roles in addition to γ

22DIS 17 workshop Daniel Britzger – Electroweak physics at LHeC & FCC-ep

Deep-inelastic electron-proton scattering

e(k)

e'(k')

p(p)

e(k)

p(p)

γ/Z(q) W(q)

ν(k')

XX

Neutral current scatteringep → e'X

Charged current scatteringep → ν

e X

R-D. Heuer"The point-like electron "probes" the interior of the proton via the electroweak force, while acting as a neutral observer with regard to the strong force."

-> Both: Electroweak (EW) and QCD physics are equally important at LHeC (?)

Q2 = -q2 = -(k-k’)2 Momentum transferx = Q2/2pq Bjorken x

2 / GeV2Q310 410

)2 (p

b/G

eV2

/dQ

σd

-710

-510

-310

-110

10

H1 and ZEUS

y < 0.9 = 318 GeVs

-1p 0.4 fb-HERA NC e-1p 0.5 fb+HERA NC ep-HERAPDF2.0 NC e

p+HERAPDF2.0 NC e

-1p 0.4 fb-HERA CC e-1p 0.5 fb+HERA CC ep-HERAPDF2.0 CC e

p+HERAPDF2.0 CC e

2 / GeV2Q310 410

)2 (p

b/G

eV2

/dQ

σd

-710

-510

-310

-110

10

Figure 74: The combined HERA NC and CC e−p and e+p cross sections, dσ/dQ2, togetherwith predictions from HERAPDF2.0 NLO. The bands represent the total uncertainty on thepredictions.

147

HERA: the last ep collider• Ee =27.6 GeV, Ep =920 GeV, √s =318 GeV•Most precise measurement of PDF (parton distribution functions) up to Q2 ~ 104 GeV2, down to x ~ 10-5

• Indispensable inputs to energy-frontier hadron collider (LHC)

3

H1 and ZEUS

xBj = 0.00005, i=21xBj = 0.00008, i=20

xBj = 0.00013, i=19xBj = 0.00020, i=18

xBj = 0.00032, i=17xBj = 0.0005, i=16

xBj = 0.0008, i=15xBj = 0.0013, i=14

xBj = 0.0020, i=13xBj = 0.0032, i=12

xBj = 0.005, i=11xBj = 0.008, i=10

xBj = 0.013, i=9xBj = 0.02, i=8

xBj = 0.032, i=7xBj = 0.05, i=6

xBj = 0.08, i=5

xBj = 0.13, i=4xBj = 0.18, i=3

xBj = 0.25, i=2

xBj = 0.40, i=1

xBj = 0.65, i=0

Q2/ GeV2

σr,

NC

x 2

i

HERA NC e+p 0.5 fb–1HERA NC e p 0.4 fb–1–

√s = 318 GeVFixed Target

HERAPDF2.0 e+p NLOHERAPDF2.0 e p NLO–

10-3

10-2

10-1

1

10

10 2

10 3

10 4

10 5

10 6

10 7

1 10 10 2 10 3 10 4 10 5

Figure 81: The combined HERA data for the inclusive NC e+p and e−p reduced cross sectionstogether with fixed-target data [106,107] and the predictions of HERAPDF2.0 NLO. The bandsrepresent the total uncertainties on the predictions. Dashed lines indicate extrapolation intokinematic regions not included in the fit.

154

MicroscopeResolvewithspectacularrange(eachhighenergyepcolliderprobesrangedowntoSLAC’s0.1fmasQ2varies)andprecision:StructureandDynamicsofProton,neutron,photon,pomeron,jets..inMomentumandTransverseSpacePDFs,TMDs,DVCS,generalisedPDFs,..presentedintheLHeCCDR1206.2913ShortversionseearXiv:1211.4831CanweconDnuethepassbegun60yearsagoforthecomingdecades?Prospectandchallenge:5ordersofmagnitudein100years

Future of DIS - ep(eA) collider

4

•Use a p(A) beam of the hadron collider, collide with a new (polarized) e-beam

•LHeC: 60 GeV e × 7 TeV p 　　　→ √s = 1.3 TeV•FCC-eh: 60 GeV × 50 TeV p 　　　→ √s = 3.5 TeV

•No major additional investment inhadron beam facility: affordable cost!•Can run concurrently with h-h collider•Higher CMS energy than e+e-

•Much cleaner environment than h-h(Negligible pile-up)← spacial resolution

10-4 fm

1/Q

M. Klein

LHeC (Large Hadron electron Collider)

4

電子 陽子 7TeV 60GeV

9 直線型加速器＋円形加速器 9 電子を60GeVまで加速 9 衝突に使われなかった電子の エネルギーを回収して、次の 電子の加速に利用

• 電子加速器 (ERL)

• 検出器

9 電子ビームの進行方向に 比べて陽子ビームの進行 方向の方が長い非対称な デザイン

New e-beam by ERL•Energy Recovery LINAC (3 turns of 2×10 GeV)•Decelerate unconsumed beam, whose power isrecycled (accel. and decel. beams in opposite RF phase)

5

ERL design•802Hz, 5-cell s.c. cavity, 18 MV/m

•Aiming at L~1034 (100 fb-1/year)

6

LHeCERLBaselineDesign

ConcurrentoperaDontopp,LHCbecomesa3beamfaclity.P<100MW.CW

D. Pellegrini, DIS17

Loca4on+FootprintoftheelectronERLLHC FCC

Energy–Cost–Physics–Footprintarebeingreinves4gated

A9kmERLisasmalladd-onfortheFCCDoublingtheenergyto120GeVhugelyIncreasescostandeffort.

Location and footprint

7

M. Klein, DIS17

Civil Eng. consideration

8

ShaftsIP

Civil EngineeringOngoing discussion about installation,point 2 is the current first choice (point8 also considered):

• Easy placement of the shafts closeto the Meyrin and Prevessin CERNsites,

• Good geology: molasse-morain,

• Separation from the LHC grantedby the tilt of the LHC tunnel.

31/22

D. Pellegrini, DIS17

Demonstrator: PERLE•8-cavity×2, 3 turns → 1 GeV e-beam, 10~20 mA

•Proposal at LAL (Orsay) with 1/2 RF (400 MeV)•Probe ERL operationin multi-MW regime•Can do low-energy, high-intensity ep/eA(γp/γA) beam physics

9

3 Design and Parameters

Figure 3.1: PERLE configuration of two parallel linacs comprising two 4-cavity cryomod-ules each to achieve 150 MeV acceleration per linac and 300 MeV per pass.There are up to three passes. There will be a pre-acceleration unit followingthe source to enter the ERL with relativistic electrons (>5 MeV).

PERLE may be constructed in stages from initially 150 MeV to nearly 900 MeV in3 steps. The final baseline design of the ERL configuration (Fig. 3.1) would consist ofthe following elements:

1. a 5 MeV to 10 MeV energy injector;

2. two 150 MeV linacs each consisting of eight 5-cell SC structures;

3. optics transport lines including spreader regions at the exit of each linac to separateand direct the beams via vertical bending, and recombiner sections to merge thebeams and to match them for acceleration through the next linac;

4. beam dump at 5�10 MeV.

Each beam recirculates up to three times through both linacs to boost the energy to900 MeV. To enable operation in the energy recovery mode, after acceleration the beam isphase shifted by 180 � and then sent back through the recirculating linac at a deceleratingRF phase. During deceleration the energy stored in the beam is reconverted to RF energyand the final beam, at its original energy, is directed to a beam dump. The set of mainparameters incorporated into the ERL prototype injector is shown in Table 3.1.

36

4tlePERLEatOrsay:NewCollabora4on:BINP,CERN,Daresbury/Liverpool,Jlab,Orsay+

CDRpublica4onimminent.

3turns,2Linacs,15mA,802MHzERLfacility

-DemonstratorofLHeC

-Technology(SCRF)DevelopmentFacility

-LowEelectronandphotonbeamphysics

-Highintensity:100xELI

Seehfps://indico.lal.in2p3.fr/event/3428/

PowerfulERLforExperiments(ep.yp):PERLEatOrsay

arXiv:1705.08783

LHeCDetector2016

PK:Status11/16

Detector design•Asymmetric energy → asymmetric detector

•Very low-angle tagging is important

10

Physics at the LHeC/FCC-he•Any interesting physics in energy-frontier ep(A)?•Yes!

11

6DIS 17 workshop Daniel Britzger – Electroweak physics at LHeC & FCC-ep

LHeC & FCC-eh: Large kinematic range

Comprehensive physics programme● Higgs physics● Top-Quark (properties, top-PDFs)● Heavy-quarks (s,c,b-quarks)● low-x physics (non-linear QCD?),

also e-Ion● Precision QCD physics (strong

coupling, PDFs)● Electroweak physics...

Huge increase of kinematical reach over previous DIS experiments

e.g.: P. Newman [NPPS 191 (2009) 307]

D. Brizger, DIS17

•Ultimate precision in PDF and αs meas.

•Higgs/top factory•EW physics•BSM searches•low-x/diffraction•eA (nuclear PDF)

Physics example: PDF

122

Kinematical coverage

x-1010 -910 -810 -710 -610 -510 -410 -310 -210 -110

( G

eV )

XM

1

10

210

310

410

510

Kinematics of a 100 TeV FCC

y=0y=-4y=-8 y=4 y=8

FCC 100 TeV

LHC 14 TeV

Plot by J. Rojo, Dec 2013Kinematics of a 100 TeV FCC

DY, low-pt jets

W,Z

Higgs, top

2 TeV squarks

20 TeV Z’

Juan Rojo FCC QCD WG Meeting, CERN, 16/04/2015

Fig. 1: Kinematical coverage in the (x, MX) plane of ap

s = 100 TeV hadron collider (solid blue line), comparedwith the corresponding coverage of the LHC at

ps = 14 TeV (dot-dashed red line). The dotted lines indicate

regions of constant rapidity y at the FCC. We also indicate the relevant MX regions for phenomenologicallyimportant processes, from low masses (Drell-Yan, low pT jets), electroweak scale processes (Higgs, W, Z, top),and possible new high-mass particles (squarks, Z 0).

treating electroweak gauge bosons as massless and their inclusion into the DGLAP evolution equations.Finally in Sect. 3.7 we discuss the possible relevance of high-energy (small-x) resummation effects for a100 TeV collider.

3.2 PDFs and their kinematical coverage at 100 TeVWe begin by quantifying the kinematical coverage in the (x, MX) plane that PDFs probe in a 100 TeVhadron collider, with MX being the invariant mass of the produced final states. In Fig. 1 we representthe kinematical coverage in the (x, MX) plane of a

ps = 100 TeV hadron collider compared with

the corresponding coverage of the LHC atp

s = 14 TeV. The dotted lines indicate regions of constantrapidity y at the FCC. In this plot, we also indicate the relevant MX regions for phenomenologicallyimportant processes, from low masses (such as Drell-Yan or low pT jets), electroweak scale processes(such as Higgs, W, Z, or top production), and possible new high-mass particles (such as a 2 TeV squarkor a 20 TeV Z 0).

In the low-mass region, for MX 10 GeV, PDFs would be probed down to x ' 5 · 10�5 in thecentral region, y ' 0, and down to x ' 5 · 10�7 at forward rapidities, y ' 5. At even forward rapidities,for example those that can be probed by using dedicated detectors down the beam pipe, PDFs couldbe probed down to x ' 10�8. While these extreme regions of very low x are not relevant for neitherelectroweak scale physics nor for high-mass New Physics searches, they are crucial for the tuning of softand semi-hard physics in Monte Carlo event generators [28] and therefore it is important to ensure thatthe PDFs exhibit a sensible behaviour in this region. Moreover, forward instrumentation would also be

8

6small%x%becomes&relevant&even&for&“common” physics&(EG.&W,&Z,&H,&t)

large%x%relevant&in&searches&for&new,&very&high&mass&states

C. Gwenlan, DIS17

PDF for E-frontier physics

13

[GeV]XM210 310 410

Ratio

0.50.60.70.80.9

11.11.21.31.41.5

Gluon-Gluon, luminosity

CT14 NNLONNPDF3.0MMHT14 NNLO

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Rat

io

0.50.60.70.80.9

11.11.21.31.41.5

Gluon-Gluon, luminosity

LHeC 17

= 1.00e+05 GeVSG

ener

ated

with

APF

EL 2

.7.1

Web

[GeV]XM210 310 410

Ratio

0.50.60.70.80.9

11.11.21.31.41.5

Quark-Antiquark, luminosity

CT14 NNLONNPDF3.0MMHT14 NNLO

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Rat

io

0.50.60.70.80.9

11.11.21.31.41.5

Quark-Antiquark, luminosity

LHeC 17

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

9

what&about&future&ep&colliders?LHeC:extremely&

precise&PDFs&across&full&

mass&range,&up&to&the&very&high&scales&

accessible&at&FCC

(see&also&talk&by&A.&CooperFSarkar)

100%TeV

100%TeV

100%TeV

100%TeV

qqbarqqbar

gg ggx

-610 -510 -410 -310 -210 -110 1

Ratio

-10-8-6-4-202468

10xg(x,Q), comparison

CT14 NNLONNPDF3.0 NNLOMMHT14 NNLOHERAPDF1.5 NNLOQ = 1.41e+00 GeV

Gen

erat

ed w

ith A

PFEL

2.4

.0 W

eb

x-610 -510 -410 -310 -210 -110 1

Ratio

-10-8-6-4-202468

10xg(x,Q), comparison

CT14 NNLONNPDF3.0 NNLOMMHT14 NNLOHERAPDF1.5 NNLOQ = 1.41e+00 GeV

Gen

erat

ed w

ith A

PFEL

2.4

.0 W

eb

FCC&parton luminosities

and&now,&what&can&the&FCC+eh do?

today …%then,%if&we&have

3%

MX [GeV]MX [GeV]

[GeV]XM210 310 410

Ratio

0.50.60.70.80.9

11.11.21.31.41.5

Gluon-Gluon, luminosity

CT14 NNLONNPDF3.0MMHT14 NNLO

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Rat

io

0.50.60.70.80.9

11.11.21.31.41.5

Gluon-Gluon, luminosity

LHeC 17

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Ratio

0.50.60.70.80.9

11.11.21.31.41.5

Quark-Antiquark, luminosity

CT14 NNLONNPDF3.0MMHT14 NNLO

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Rat

io

0.50.60.70.80.9

11.11.21.31.41.5

Quark-Antiquark, luminosity

LHeC 17

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

9

what&about&future&ep&colliders?LHeC:extremely&

precise&PDFs&across&full&

mass&range,&up&to&the&very&high&scales&

accessible&at&FCC

(see&also&talk&by&A.&CooperFSarkar)

100%TeV

100%TeV

100%TeV

100%TeV

qqbarqqbar

gg ggx

-610 -510 -410 -310 -210 -110 1

Ratio

-10-8-6-4-202468

10xg(x,Q), comparison

CT14 NNLONNPDF3.0 NNLOMMHT14 NNLOHERAPDF1.5 NNLOQ = 1.41e+00 GeV

Gen

erat

ed w

ith A

PFEL

2.4

.0 W

eb

x-610 -510 -410 -310 -210 -110 1

Ratio

-10-8-6-4-202468

10xg(x,Q), comparison

CT14 NNLONNPDF3.0 NNLOMMHT14 NNLOHERAPDF1.5 NNLOQ = 1.41e+00 GeV

Gen

erat

ed w

ith A

PFEL

2.4

.0 W

eb

FCC&parton luminosities

and&now,&what&can&the&FCC+eh do?

today …%then,%if&we&have

3%

MX [GeV]MX [GeV]

18

summary&of&FCCFeh&PDFs

x7−10 6−10 5−10 4−10 3−10 2−10 1−10 1

xf(x

,Q)

0

0.5

1

1.5

2

2.5PDF4LHC NNLO MC PDFs

(x,Q)bx(x,Q)cx(x,Q)sx(x,Q)ux(x,Q)dx

xg(x,Q)xd(x,Q)xu(x,Q)xs(x,Q)xc(x,Q)xb(x,Q)Q = 1.41e+00 GeV

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

x7−10 6−10 5−10 4−10 3−10 2−10 1−10 1

xf(x

,Q)

0

0.5

1

1.5

2

2.5PDF4LHC NNLO PDFs

(x,Q)cx(x,Q)sx(x,Q)ux(x,Q)dx

xg(x,Q)xd(x,Q)xu(x,Q)xs(x,Q)xc(x,Q)Q = 1.41e+00 GeV

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Rat

io

0.7

0.8

0.9

1

1.1

1.2

1.3Quark-Antiquark, luminosity

LHeC 17FCC-eh 17

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Rat

io

0.7

0.8

0.9

1

1.1

1.2

1.3Gluon-Gluon, luminosity

LHeC 17FCC-eh 17

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

FCCFeh&PDFPDF4LHC15

100%TeV 100%TeV

gg qqbar

C. Gwenlan, DIS17

[GeV]XM210 310 410

Ratio

0.50.60.70.80.9

11.11.21.31.41.5

Gluon-Gluon, luminosity

CT14 NNLONNPDF3.0MMHT14 NNLO

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Rat

io

0.50.60.70.80.9

11.11.21.31.41.5

Gluon-Gluon, luminosity

LHeC 17

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

[GeV]XM210 310 410

Ratio

0.50.60.70.80.9

11.11.21.31.41.5

Quark-Antiquark, luminosity

CT14 NNLONNPDF3.0MMHT14 NNLO

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb [GeV]XM

210 310 410R

atio

0.50.60.70.80.9

11.11.21.31.41.5

Quark-Antiquark, luminosity

LHeC 17

= 1.00e+05 GeVS

Gen

erat

ed w

ith A

PFEL

2.7

.1 W

eb

9

what&about&future&ep&colliders?LHeC:extremely&

precise&PDFs&across&full&

mass&range,&up&to&the&very&high&scales&

accessible&at&FCC

(see&also&talk&by&A.&CooperFSarkar)

100%TeV

100%TeV

100%TeV

100%TeV

qqbarqqbar

gg ggx

-610 -510 -410 -310 -210 -110 1

Ratio

-10-8-6-4-202468

10xg(x,Q), comparison

CT14 NNLONNPDF3.0 NNLOMMHT14 NNLOHERAPDF1.5 NNLOQ = 1.41e+00 GeV

Gen

erat

ed w

ith A

PFEL

2.4

.0 W

eb

x-610 -510 -410 -310 -210 -110 1

Ratio

-10-8-6-4-202468

10xg(x,Q), comparison

CT14 NNLONNPDF3.0 NNLOMMHT14 NNLOHERAPDF1.5 NNLOQ = 1.41e+00 GeV

Gen

erat

ed w

ith A

PFEL

2.4

.0 W

eb

FCC&parton luminosities

and&now,&what&can&the&FCC+eh do?

today …%then,%if&we&have

3%

MX [GeV]MX [GeV]

Relevance of ultra-precise PDF•PDF-uncertainty of Higgs cross section squeezes to be sensitive to mH

14

12

LHeC PDFs for Higgs at the LHC!ggH is dominant Higgs production mechanism at LHC!!

44

46

48

50

52

54

56

58

60

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

!"#$%&&'()&*+,#-./0+.1&23&)-#40,.#4&"&,-255&5#,62+&05&789:;&<515=5./>?&*50+@&!"#$&2+A18&&!#/45&.2&"&B/55&5#+506C0.18&&&D.-2+@&,2*)A0+@&*+4#-A10+@&&)/-/B#.#-&<7877:&!&E7;>8&!"#$%&787779&F&&G##45&GH!I&&"J&.-#/.B#+.&0B)2-./+.&&K&

L-#,0502+&32-&"0@@5&/.&.M#&!"$&

I8N-O+0+@&/+4&P8QA#0+&/-R0C%EH7:897S7?&PL!T&97EH&&

LHeC PDF: 0.3% on cross section (experimental stat.+syst.)!!

sensitivity to Higgs mass!!!αs is underlying parameter:

0.005 change � 10% on cross section LHeC: αs to per mille (0.0002)!!

!need N3LO to reduce scale

uncertainty: now available for ggH!!!!

LHeC with high luminosity is in itself a precision Higgs facility!C. Gwenlan, PDFs and QCD at the LHeC

arXiv:1305.2090"

•High-mass gluino xsec uncertainty >> 100%→ squeezes to < 10％

Even

ts

-110

1

10

210

310

410

510

610

710Data 2012

*�Z/Photon-InducedTop quarksMulti-Jet & W+JetsDiboson

= 14 TeVLL-

�

= 14 TeVLL+�

= 3.5 TeV (GRW)sM

ATLAS-1 L dt = 20.3 fb�ee:

= 8 TeVs

[TeV]eem0.1 0.2 0.3 0.4 1 2 3 4

Dat

a / B

kg

0.60.8

11.21.4

11

high x PDFs: link to LHC!•  large uncertainties in high x PDFs limit searches for new physics at high scales!

many interesting processes at LHC are gluon-gluon initiated: top, Higgs, … and BSM processes, such as gluino pair production!

current BSM search in dilepton final state; uncertainties on high-x (anti)quarks dominate!

LHeC PDF

arXiv:1211.5102"

arXiv:1407.2410"

C. Gwenlan, PDFs and QCD at the LHeC

arXiv:1305.2090

Strong coupling constant

1522

strong coupling from LHeC combined fit to PDFs+αs using LHeC data !

~ 0.3% precision from LHeC!!

LHeC could resolve a > 30-year old puzzle:!αs consistent in inclusive DIS, versus jets? !

Voica Radescu | |Washington, D.C. | 2015

Strong coupling from FCC eh! The much reduced PDFs impose better constraints on various SM and BSM parameters:!

!! alphas small in DIS or high with jets?!

! [over 30 years old puzzle HERA couldn't solve]!!

!!

!!!!!!!!!!!

14

~0.3 % precision from LHeC

PRELIMIN

ARY

H1 and ZEUS

0

20

40

0.105 0.11 0.115 0.12 0.125 0.13

!2 - !m

in2

NLOinclusive + charm + jet data, Q2inclusive + charm + jet data, Qmin = 3.5 GeV2

inclusive + charm + jet data, Q2inclusive + charm + jet data, Qmin = 10 GeV2

inclusive + charm + jet data, Q2inclusive + charm + jet data, Qmin = 20 GeV2

0

20

40

0.105 0.11 0.115 0.12 0.125 0.13

!2 - !m

in2

NLOinclusive data only, Q2inclusive data only, Qmin = 3.5 GeV2

inclusive data only, Q2inclusive data only, Qmin = 10 GeV2

inclusive data only, Q2inclusive data only, Qmin = 20 GeV2

0

20

40

0.105 0.11 0.115 0.12 0.125 0.13

"s(MZ2)

!2 - !m

in2

NNLOinclusive data only, Q2inclusive data only, Qmin = 3.5 GeV2

inclusive data only, Q2inclusive data only, Qmin = 10 GeV2

inclusive data only, Q2inclusive data only, Qmin = 20 GeV2

a)

b)

c)

Figure 63: ∆χ2 = χ2 − χ2min vs. αs(M2Z) for pQCD fits with different Q2min using data on (a)

inclusive, charm and jet production at NLO, (b) inclusive ep scattering only at NLO and (c)inclusive ep scattering only at NNLO.

132

M Klein, V Radescu! NC,CC!NC,CC+F2c!

expected 0.1% precision when combined with HERA!

C. Gwenlan, PDFs and QCD at the LHeC

C. Gwenlan, QCD@LHC 2015

ep collider as Higgs factory•

16

(GeV)jjM0 20 40 60 80 100 120 140 160 180 200

/10G

eV-1

Even

ts/1

ab

0

500

1000

1500

2000

2500higgs+bkg

CCjjj no top

CC single topCC Z

NC Z

PAjjj

signal

Cut based results: H→bb at LHeC 8• Assumed 1000 fb-1 of statistics. (~10 years running for LHeC.) • Veto efficiency of 90% for photo-production background is assumed,

using forward electron tagging.

Signal: 3600 Bkg: 1250 κ(Hbb) ~ 0.97%

Mass of 2 b-jets (GeV)

κ =

Precision of coupling constant (Statistics error only)

�pjjj

S/B ~2.9

• Note: In previous presentations we considered twice number of background for coupling error over-conservatively.

M. Tanaka, DIS17(cut-based analysis)

Applying BDT analysis further increases statistics (next page) →

SM Higgs into HFL Summary

Uta$Klein,$Higgs@FCCBeh$ 9

Huge statistics Higgs physics

17FCC week, Berlin, June 2017

•Polarization of e-beam possible (80%)

•Inclusive NC and CC events → EW & PDF fits

•E.g. W mass from CC → very competitive

14DIS 17 workshop Daniel Britzger – Electroweak physics at LHeC & FCC-ep

Weak-boson massesW-boson mass from NC&CC DIS data

● All other masses expected to be known● HERA ± 63(exp )29(PDF)

● LHeC ± 14(exp )10(PDF)

● FCC ± 9(exp )4(PDF)

Competitive W-boson mass● CC kinematics constraint by IS + FS

measurements -> no missing ET needed !!

● PDF uncertainties are small

W-boson masss at high precision

HERA prospects (1987)m

W~ ± 80-100 MeV

Our HERA valuem

W~ ± 63

(exp )29

(PDF)

Inner errors: exp. onlyOuter errors: exp. + PDF

preliminary

± 15 MeV

Electroweak physics

18

10DIS 17 workshop Daniel Britzger – Electroweak physics at LHeC & FCC-ep

Polarised Charged Current DIS

Q2 = 3000 GeV2

y ~ 0.25

sFCCeh

/ sHERA

~ 30

1ab-1

0.3ab-1

0.1ab-1

FCC-eh

H1 data

SM expectation

σ-

CC[P

e=+1] = 0

σ+

CC[P

e=-1] = 0

e-

e+

preliminary

CC depends on longitudinal polarisation● W-boson couples only to left-handed particles

LHeC and FCC● Huge cross section due to √s● For fixed (Q2,y), increase due lower x values

-> Gluon induced processes

-> Helicity effects important at high-x (only)

Most data: electrons with P~-80%

D. Britzger, DIS17

LQM

0 500 1000 1500 2000 2500 3000 3500

LQλ

-310

-210

Monica D'Onofrio, 1st FCC physics week 14

LQ status and reach at FCC -eh

LHeC

FCC-eh 60GeV

1st generation LQs ! Current constraints almost there with 3.2/fb @ 13 TeV

ep scenario: sensitive to λ << e=√4πα=0.03

1/19/2017

(λLQ = 0.03 = LHC ‘usual’ l)!

Sensitivity of HL-LHC could go to ~2.8 – 2.9 TeV ! Close to the reach for FCC-eh ! Dependence on lambda If deviations are found by the end of HL-LHC, FCC-hh will definitely see them, and FCC-eh can characterize those signals!

Current LHC

3000/fb @ 14 TeV ~ 2.9 TeV reach (use http://collider-reach.web.cern.ch)

LFCC-eh = 500fb-1!

•Example: Leptoquarks

•Production depends one-q-LQ coupling λ

•For usual couplings, LQ found in (HL-)LHC would be found also in ep

•ep collider has handles todetermine LQ quantum #’s‒ e+/e- beam, polarization‒ spin and generation

•Also interesting opportunities on top physics (FCNC, ...) and BSM Higgses (not shown today)

Beyond SM searches

19

LQ production

1/19/2017 Monica D'Onofrio, 1st FCC physics week

Leptoquarks (LQs) appear in several extensions to SM: production σ ∼#

can be scalar or vector, with fermion number 0 (e-qbar) or 2 (e-q)

•  At the p-p, mostly pair production (from gg or qq)

!  if λ not too strong (0.3 or lower)

cross section independent on λ#

13

5.2 Leptoquarks and leptogluons

The high energy of the LHeC extends the kinematic range of DIS physics to much highervalues of electron-quark massM =

⌅sx, beyond those of HERA. By providing both baryonic

and leptonic quantum numbers in the initial state, it is ideally suited to a study of theproperties of new bosons possessing couplings to an electron-quark pair in this new massrange. Such particles can be squarks in supersymmetric models with R-parity violation( ⇤Rp), or first-generation leptoquark (LQ) bosons which appear naturally in various unifyingtheories beyond the Standard Model (SM) such as: E6 [44], where new fields can mediateinteractions between leptons and quarks; extended technicolor [47, 538], where leptoquarksresult from bound states of technifermions; the Pati-Salam model [45], where the leptonicquantum number is a fourth colour of the quarks or in lepton-quark compositeness models.They are produced as single s�channel resonances via the fusion of incoming electrons withquarks in the proton. They are generically referred to as “leptoquarks” in what follows.The case of “leptogluons”, which could be produced in ep collisions as a fusion between theelectron and a gluon, is also addressed at the end of this section.

5.2.1 Phenomenology of leptoquarks in ep collisions

In ep collisions, LQs may be produced resonantly up to the kinematic limit of⌅s via the

fusion of the incident lepton with a quark or antiquark coming from the proton, or exchangedin the u channel, as illustrated in Fig. 5.5. The coupling � at the LQ � e � q vertex is an

e+

d

LQ

e+

d(a)

e+ e+

LQ

d– d–

(b)

Figure 5.5: Example diagrams for resonant production in the s-channel (a) and exchangein the u-channel (b) of a LQ with fermion number F = 0. The corresponding diagrams for|F | = 2 LQs are obtained from those depicted by exchanging the quark and antiquark.

unknown parameter of the model.

In the narrow-width approximation, the resonant production cross section is proportionalto �2q(x) where q(x) is the density of the struck parton in the incoming proton.

The resonant production or u-channel exchange of a leptoquark gives e+ q or ⇥+ q� finalstates leading to individual events indistinguishable from SM NC and CC DIS respectively.For the process eq ⇥ LQ ⇥ eq, the distribution of the transverse energy ET,e of the finalstate lepton shows a Jacobian peak at MLQ/2, MLQ being the LQ mass. Hence the strategyto search for a LQ signal in ep collisions is to look, among high Q2 (i.e. high ET,e) DISevent candidates, for a peak in the invariant mass M of the final e� q pair. Moreover, thesignificance of the LQ signal over the SM DIS background can be enhanced by exploitingthe specific angular distribution of the LQ decay products (see spin determination, below).

188

λ λ

•  At the e-p: both baryon and lepton quantum

numbers – ideally suited to search for and

study properties of new particles coupling to

both leptons and quarks

•  single, resonant production; sensitive to λ

G. Azuelos

M. D’Onofrio, FCC physics week

e.g. “b-Sat” Dipole model - “eikonalised”: with impact-parameter

dependent saturation - “1 Pomeron”: non-saturating

•  Significant non-linear effects expected in LHeC kinematic range.

With detailed exploration of ep and eA, including t dependences, this becomes a powerful

probe!...

[2 fb-1] The analysis framework

The fit framework same as in the EPPS16 analysis [EPJ C77, 163]

Include the same data as in EPPS16 plus LHeC (NC and CC) pseudo data.

Hessian uncertainty analysis with ��2 = 52 (as in EPPS16)

1

10

102

103

104

105

10-4

10-3

10-2

10-1

1

fixed target DIS and DYLHC dijetsLHC W & ZCHORUS neutrino dataPHENIX

x

Q2[G

eV2]

⇡

0

x-610 -510 -410 -310 -210 -110 1

)2

(G

eV

2Q

-110

1

10

210

310

410

510

610)2(x,Q

2,Anuclear DIS - F

Proposed facilities:

LHeC

Fixed-target data:

NMC

E772

E139

E665

EMC

(Pb, b=0 fm)2s

Q

perturbative

non-perturbative

(70 GeV - 2.75 TeV)

e-Pb (LHeC)

H. Paukkunen for the LHeC study group An update on nuclear PDFs at the LHeC

Diffraction / Nuclear PDF•Diffractive physics withlarge rapidity gap and/orRoman-pot spectrometer

•e+p, e+Pb (and more?)for nuclear effects incompletely new kinematics

20

About the functional forms

However, the Hessian method used e.g. in EPPS16 is not particularlyaccurate when there’s no, or only very weak constraints

• Significant non-quadratic components in the global �2 function

• Large correlations among the fit parameters

Would need Monte-Carlo methods to more reliably map the uncertainties

=) Further work needed

Despite all the shortcomings, a typical result using a more flexible form(the red one in the previous slide) for the gluons:

x

R

Pb

g

(x,Q

2=10

GeV

2)

x

R

Pb

g

(x,Q

2=10

GeV

2)

No LHeC data LHeC data included

H. Paukkunen for the LHeC study group An update on nuclear PDFs at the LHeC

P. Newman, DIS17

H. Paukknen, DIS17N. Armesto

Conclusions•A new electron-hadron collider, using a hadron beam of existing/planned hadron colliders, is a cost-effective and attractive future program.

•An ERL with 60 GeV is extensively designed by experts anda demonstrator PERLE is proposed.

•ep (eA) energy frontier machine with 100× Q2 reach and 1000× luminosity of HERA → rich physics program complementary to HL-LHC and FCC-hh

•Different objective from low-energy machine EIC in US, which focuses on spin and medium-x structure of nucleons/nuclei.

•A dedicated workshop happens 11-13/Sep:https://indico.cern.ch/event/639067

•Also visit http://cern.ch/lhec/ 21