CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Recorded at

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Where are we with the Higgs ?

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Why all the excitement about the Higgs ? Like all the other fields the Higgs field is omnipresent. The role of the Higgs field is to give mass to all particles. Understanding the Higgs field could mean understanding the masses of the fundamental particles (fields) The Higgs field could naturally contribute to an explanation of the accelerating expansion of the Universe. Does the Higgs particle exist and will its existence be confirmed at CERN or at Fermilab ?

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Other questions for the LHC - What happened to the Antimatter in the Universe ? - Can all the Forces and Particles be unified ? (Super Symmetry) - Did the Universe go through a Phase of Quark-Gluon Plasma ? Super Strings - Can General Relativity and Quantum Mechanics be unified ? - Are the Fundamental Particles two-dimensional Strings ? - Does the Universe have more than three Spatial Dimensions ? - Accelerating Expansion of the Universe and Dark Matter

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Matter Anti Matter What happened to the Anti Matter ?

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Was there a perfect symmetry between matter and antimatter in the early Universe ? The answer must be no !

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Before time = 1 microsecond (after Big Bang): Energy protons + antiprotons After time = 1 microsecond: Energy protons + antiprotons Small excess (1/ ) of protons ? ( CP violation) time = 1 µs : The big antimatter massacre: protons antiprotons = 1 proton + energy

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen CP violation observed Needs tree quark-lepton families to be explained Studied at CERN, SLAC, KEK, Fermilab Does not yet explain the Matter Antimatter asymmetry CP violation to be studied extensively at the LHC

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen The Supersymmetry Puzzle there has to be some sort of connection between the matter and the force particles ! Putting the matter particles and the force carrying particles together in a common scheme is a strange puzzle. The final puzzle is full of holes that has to be filled by new particles. These are the Supersymmetric Particles, and the Higgs fields are needed !

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen the Supersymmetric Particles ? may be produced in pairs at the LHC ? - The lightest SS Particle “must” be stable, - it must have been produced together with all the other matter particles in the Big Bang - it must be much heavier than protons, and - will therefore dominate the mass content of the universe Supersymmetric particles may explain the Dark Matter problem in Astrophysics

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Unification of forces: the electromagnetic, weak and strong forces These forces are very different at low energies, but may they come together at very high energies ? and what about gravity ? superstrings and extra dimensions How heavy are the Higgses, and the supersymmetric particles (can they be produced at the LHC ? Energy? Intensity?) The lightest Higgs particle was within reach of LEP ?? For answers to the others we have to look at:

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen How the forces vary with distance Classical electrostatics (Coulomb’s law): F = k (q 1 q 2 )/r 2 Classical gravitation (Newton): F =  (M 1 M 2 )/r 2 In a quantum field theory the “constants” k and  will vary with energy (Vacuum Polarization) Is it possible that all the forces of Nature have the same strength at a certain (very high) energy?

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen The “strength” of the strong force (running of the Coupling “Constant”  S )

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Unification of the Coupling Constants in the SM and the minimal MSSM

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Unification of Gravity with the other forces From a simple extrapolation this should happen at an energy scale of GeV or a length scale of m But only superstring theory is capable of unifying all the forces. Superstring theory contains supersymmetry. Superstrings are objects with 1 spatial dimension moving in a world of 9, but where all but three dimensions are curled up on an unobservable scale ! The # of dim. for the EM field is tested to be 3 down to m, but gravity is tested only down to mm scale ! ! Is unification of all the forces possible at the TeV scale ?

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen How many macroscopic dimensions can we “see”? gravitation and light (electromagnetism) tell us: three macroscopic dimensions In N dimensions: field lines spread out, i.e. field weakens as 1/r N-1

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen “One-dimensional” garden hose

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen One curled-up dimension

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Two curled-up dimensions

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Two curled-up dimensions (another topology)

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Six curled-up dimensions (Calabi - Yau topology)

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Particles as Super Strings Strings and extra dimensions:.... Two-dimensional (“normal”) Space Extra Dimension Graviton

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen to m Gravity may curl up differently than the other forces. Gravity may be weak because it has continued to spread out in more than 3 dimensions up to a larger scale than the other fields.

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Gravitons may have the freedom to move in more dimensions than other particles Gravitons may be produced in large numbers at the unification scale and disappear into the hidden dimensions (missing energy) New particles and micro black holes corresponding to m sizes would be produced.

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen 1 mm billions of light years Parallel universes gravity curled up at millimeter scale Gravity from galaxy on neighboring sheet may be weakly felt

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen 1 mm One universe (folded) Gravity from galaxy on neighboring sheet (mm distance ) can be weakly felt. Light has to go billions of light years. billions of light years

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Need large, hermetic and very performant detectors

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen See:

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen CMS

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen Supersymmetric particles (or something unforeseen) will turn up around TeV energies Free Energy ( E F ): E F prop. to E Proton E F equal to 2xE Proton Fixed target Collider BUT: E Quark is on average only 1/6 of E Proton

CERN, 21 February 2001 Egil Lillestøl, CERN & Univ. of Bergen With decreasing probability the quarks can carry an increasing fraction of the proton energy So, in order to produce new particles of up to a few TeV we need a collider with total energy of at least TeV -quark quark collisions are in themselves rare -Some of the hypothetical particles will appear with very low probabilities High Luminocity needed. Also total Energy may be traded with Luminocity The will do the job !