Future High-Energy Colliders: Theoretical Vision Juan Rojo VU - - PowerPoint PPT Presentation

Future High-Energy Colliders: Theoretical Vision

Juan Rojo VU Amsterdam & Theory Group, Nikhef Nikhef Topical Lectures on Future Colliders Nikhef, Amsterdam, June 2018

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Lecture Schedule

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

High-Energy Physics in the Higgs Boson Era: where do we stand? Standard Model calculations for precision phenomenology at hadron colliders Lepton colliders: ILC, CLIC, FCC-ee, …. Hadron colliders: High-Luminosity LHC, High-Energy LHC, FCC-hh,… Lepton-hadron colliders: EIC, LHeC, FCC-eh, ….. The cosmic connection: neutrino telescopes, cosmic rays, gravitational waves

Building on material in talks/lectures from Michelangelo Mangano, Josh Ruderman, Max and Uta Klein, Matthias Neubert, …, as well as in the various CDRs / Yellow Reports (apologies for any missing references)

High-energy physics in the Higgs Boson era

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Outstanding questions in Particle Physics

Huge gap, 1017, between Higgs and Plank scales Elementary or composite? Additional Higgs bosons? Coupling to Dark Matter? Role in cosmological phase transitions? Is the vacuum state of the Universe stable?

The Higgs boson

1 GeV (Proton mass) 125 GeV (Higgs mass) 1017 GeV (Planck scale)

With radiative corrections, the natural value of the Higgs mass is Planck scale

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Degrassi et al 12

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Outstanding questions in Particle Physics

Huge gap, 1017, between Higgs and Plank scales Elementary or composite? Additional Higgs bosons? Coupling to Dark Matter? Role in cosmological phase transitions? Is the vacuum state of the Universe stable?

The Higgs boson

Weakly interacting massive particles? Sterile neutrinos? Extremely light particles (axions)? Interactions with Standard Model particles? What is the structure of the Dark Sector? Is Dark Matter self-interacting?

Dark Matter

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Outstanding questions in Particle Physics

Huge gap, 1017, between Higgs and Plank scales Elementary or composite? Additional Higgs bosons? Coupling to Dark Matter? Role in cosmological phase transitions? Is the vacuum state of the Universe stable?

The Higgs boson

Weakly interacting massive particles? Sterile neutrinos? Extremely light particles (axions)? Interactions with Standard Model particles? What is the structure of the Dark Sector? Is Dark Matter self-interacting?

Dark Matter

Why three families? Can we explain masses and mixings? Origin of Matter-Antimatter asymmetry in the Universe? Are neutrinos Majorana or Dirac? CP violation in the lepton sector?

Quarks and leptons

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

The mysteries of the Higgs sector

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

v

V

m

V

κ

• r

v

F

m

F

κ

4 −

10

3 −

10

2 −

10

1 −

10 1

W t Z b µ τ

SM Higgs boson ] fit ε [M, σ 1 ± σ 2 ±

(13 TeV)

• 1

35.9 fb

CMS Preliminary

Particle mass [GeV]

1 −

10 1 10

2

10

Ratio to SM

0.5 1 1.5

V

Agreement with SM predictions at 10% level … But no idea whatsoever of the underlying microscopic mechanism of EWSB! What physics determine the shape of the Higgs potential? What dynamics fix the values of the Higgs-matter couplings? Only couplings to third- generation fermions explored so far

The triumph of the Standard Model

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Extremely powerful, validated in thousands of different measurements We should be proud of it: perhaps the most successful physical theory ever formulated!

pp

500 µb−1 80 µb−1

W Z t¯ t t

t-chan

WW H

total t¯ tH VBF VH

Wt

2.0 fb−1

WZ ZZ t

s-chan

t¯ tW t¯ tZ tZj 10−1 1 101 102 103 104 105 106 1011

σ [pb]

Status: March 2018

ATLAS Preliminary Run 1,2 √s = 7,8,13 TeV

Theory LHC pp √s = 7 TeV Data 4.5 − 4.9 fb−1 LHC pp √s = 8 TeV Data 20.2 − 20.3 fb−1 LHC pp √s = 13 TeV Data 3.2 − 36.1 fb−1

Standard Model Total Production Cross Section Measurements

The LHC roadmap

The Large Hadron Collider is perhaps the best machine to address some of these questions For the next 20 years, LHC will be the forefront of the exploration of the high-energy frontier

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

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Only 5% of the full LHC dataset on tape Lots of exciting physics to harvest!

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

The LHC roadmap

The Large Hadron Collider is perhaps the best machine to address some of these questions For the next 20 years, LHC will be the forefront of the exploration of the high-energy frontier

What do we look for in HEP experiments?

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

known knowns

known unknowns unknown unknowns

unknown knowns

Standard Model

ex) dark matter, baryogenesis, inflation, quantum gravity, …

Rumsfeld’s Matrix of Particle Physics

things we think we know but we don’t know

“known” new physics surprises

• J. Ruderman FCC week 2018

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Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

known knowns

known unknowns unknown unknowns

unknown knowns

Standard Model

ex) dark matter, baryogenesis, inflation, quantum gravity, …

Rumsfeld’s Matrix of Particle Physics

things we think we know but we don’t know

“known” new physics surprises

• J. Ruderman FCC week 2018

+ Input to BSM searches, e.g. PDFs + Novel SM phenomena, e.g. BFKL physics + Heavy ions, soft QCD, …. + Sterile neutrinos, axions, info about EWSB, … + New interactions/particles/ spacetime dimensions? + Exploration of the high-energy frontier!!

What do we look for in HEP experiments?

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If BSM physics is too heavy and beyond the reach of the LHC, its effects could still be present in kinematic distributions due to virtual corrections Generic BSM scenarios can be parametrised in a model-independent way in terms of higher- dimensional operators: the SM Effective Field Theory (SMEFT): A large number of these operators can be directly probed at the LHC For instance, some operators contributing to inclusive jet, dijet, and multi-jet production are: Crucially, no dedicated searches are required: we can exploit all the excellent measurements that the LHC has (and will) produce, provided theoretical calculations are up to par

How to search for the unknown

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

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The SM Effective Field Theory framework accounts for a variety of potential bSM effects, from the TeV scale all the way up to the GUT scale

How to search for the unknown

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

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BSM physics could manifest as subtle deviations wrt to the Standard Model predictions Even for high-mass resonances, theory uncertainties degrade or limit many BSM searches The robustness of global stress-tests of the SM (electroweak fit, SM Effective Field Theory analysis) relies crucially in high-precision theoretical calculations BSM physics might very well hiding itself in the tails of distributions

To enhance the discovery potential of new Beyond the Standard Model physics!

Marco Farina, HL/HE LHC workshop Generic SMEFT expansion

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

How to search for the unknown

Energy helps accuracy

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Recent progress in theoretical calculations has demonstrated that the LHC is not only a discovery machine: it can (and should!) carry out a precision physics program

Farina et al 16

Electroweak precision tests at the LHC are possible Constraints on some SMEFT EW

• perators can markedly improve LEP

bounds Exploiting increase in partonic energy

eg constraints on “oblique” operators from high-mass ATLAS and CMS Drell-Yan (NC and CC) data

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Energy helps accuracy

17

Recent progress in theoretical calculations has demonstrated that the LHC is not only a discovery machine: it can (and should!) carry out a precision physics program

Farina et al 16

Electroweak precision tests at the LHC are possible Constraints on some SMEFT EW

• perators can markedly improve LEP

bounds Exploiting increase in partonic energy

eg constraints on “oblique” operators from high-mass ATLAS and CMS Drell-Yan (NC and CC) data

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

A shout-out from the bottom

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Currently the most intriguing deviation from the SM at the LHC from B meson sector If confirmed, could have observable consequences in BSM searches: Z’, leptoquarks, …

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

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Dark Matter

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Direct searches for WIMP Dark Matter are squeezing the available parameter space: soon will be limited by the “neutrino floor”: dark matter detectors as solar neutrino experiments? XENON1T: World’s most stringent limits on WIMP dark matter

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Dark Matter

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Direct searches for WIMP Dark Matter are squeezing the available parameter space: soon will be limited by the “neutrino floor”: dark matter detectors as solar neutrino experiments?

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Dark Matter

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Direct searches for WIMP Dark Matter are squeezing the available parameter space: soon will be limited by the “neutrino floor”: dark matter detectors as solar neutrino experiments?

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Dark Matter at colliders

Juan Rojo Nikhef Topical Lectures on Future Colliders, June 2018

Searches for WIMP Dark Matter are a very important ingredient of the LHC program Collider searches for DM are not competitive for other scenarios, e.g. Axion dark matter Compelling evidence for specific DM scenarios can only come from a combination of Indirect, Direct, and Collider experiments Future colliders can further push the exploration of the WIMP hypothesis, which is theoretically well motivated and that appears in BSM extensions addressing other SM problems