INVASIONS IN PARTICLE PHYSICS Compton Lectures Autumn 2001 Lecture 10 Dec

2 Lecture 10 wishlist Standard Model issues SUSY and STRINGS EXTRA DIMENSIONS THEORY SPACE COSMIC CONNECTIONS and what have you.

3 To complete the brilliant STANDARD MODEL :  THE HIGGS  CP VIOLATION (cosmic connection-matter, not antimatter universe)  NEUTRINO MASSES (cosmic connection, dark matter) Then we will find something new (the coming invasions by 2017)  Supersymmetry or new types of composite matter or extra dimensions or “other stuff”, maybe a combination of the above. (why not nothing?)

4 Arrange it so delicately that it will fall down in 19 minutes. To avoid fine tuning add new degrees of freedom:new physics

cm Planck scale G N ~l Pl cm Electroweak scale range of weak force mass is generated (W,Z) strong, weak, electromagnetic forces have comparable strengths cm Hubble scale size of universe l u Important lengths (spacetime)

6 To avoid fine tuning add new degrees of freedom: extra dimensions (oy)

Edwin Abott Gustav Fechner, 1846, ”Space has four dimensions” Plato, Allegory of the Cave- The Republic

Gunnar Nordstrom Uber die Moglichkeit das electromagnetiche Feld und das Gravitationsfeld zu vereiningen Phys. Z. 15, : : : Abstract. It is shown that a unified treatment of the electromagnetic and gravitational fields is possible if one views the four dimensional space time as a surface in a five dimensional world

Thedor Kaluza Oscar Klein Kaluza Th.Sitzungsber. Press.Akad.Wiss.Math K1 (1921) 966 Klein O. Z.Phys. 37 (1926) 895

11 Kaluza and Klein started from 5-dim gravity and derived 4-dim gravity plus electromagnetism They compactified the 5th dimension around a circle of radius R (“cylinder condition”) 5 4

12 The PLANCK Mass/Energy Scale is connected to the strength of GRAVITY The PLANCK Mass/Energy Scale is connected to the strength of GRAVITY G N =1/(M P ) 2 F=G N m1m2m1m2r2r2m1m2m1m2r2r2 M P ~ GeV (proton mass 1GeV)

13 In the Kaluza-Klein theory the 5th dimension is compactified in a cylinder with radius R= cm

14 Kaluza-Klein modes If a spatial dimension is periodic then the momentum in that dimension is quantized: From our dimensions of view the KK modes get mass: p 0 KK momentum tower of states

15 For a compact space of size R physical processes with momenta greater that 1/R will probe the extra dimensions. From our 3+1 dimensions view this means exciting Kaluza-Klein modes of gravity (or other fields). These modes to us appear as discrete massive modes in units of 1/R. How large are the string theoretical extra dimensions? As small as the Planck scale and as large as a TeV.

Arkani-Hamed DimopoulosDvali “Cylinder condition” again As large as a millimeter

(Multi)Braneverse The Standard Model is trapped on a brane and does not feel dimensions transverse to the brane

18 Pick the effective (higher dimensional) Planck Scale at 1TeV, then Solar system Pinhead Gold atom

Eot-WashGroup : No deviation from Newton’s Law was found down to 0.01”

100u (Price &Long)

22 Mother brane G Our world brane Randall - Sundrum Infinite 5th dimension! No compactification. It matters where your brane is. Zero mode graviton is trapped on the mother brane (Planck brane) 5th dimension Infinite

Lykken- Randall It does not matter where your brane is. Kaluza-Klein modes; Rich phenomenology More brane-building scenarios  3 branes (Gregory,Rubakov,Sibiryakov, Kogan et al, ….)  Folding branes and parallel universes (Arkani-Hamed, Dimopoulos …)  Longitudinal extra dimensions / stringy effects (Antoniadis, Dimopoulos,Peskin,...)

24 A lot of Kaluza-Klein states accessible at TeV or sub-TeV energy Lots of weirdness   Lots of experimental action  to confirm or kill them

25 Particle collisions window to extra dimensions dimensions At high energy particle collisions we can investigate real and virtual Kaluza Klein graviton (and other) states. They look to us like massive copies of the graviton.

26 Two events are graviton simulation and one is real CDF data: Can you pick the gravitons?

27 Two events are real CDF data and one is graviton simulation; Can you pick the graviton?

28 e.g. Missing Energy + jet qqbar->g G (n=2, M=1TeV,  s=1.8TeV

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30 With the Tevatron RunII we can explore extra dimensions up to 7 TeV and with the upcoming LHC at CERN up to 13 TeV !

31 Davoudiasl, Hewett,Rizzo 1500 GeV KK graviton/ its tower of states at LHC

32 W boson KK excitations at LHC (Accomando,Antoniadis,Benakli) Longitudinal Extra Dims-“Stringy” Scenarios

33 A spin 2 graviton: Can we tell? 1.5 TeV graviton in Randal Sundrum

34 Collider Black Hole Production? If the Planck scale is the TeV scale, gravity becomes strong at the TeV scale : In high energy particle collisions short-lived microscopic black holes will be created These decaying black holes could be observed in future colliders, such as CERN’s LHC! p p (any bets?)

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36 Black Hole production at high energy collisions (Banks et al., Dimopoulos et al. Giddings et al.) L. BORISSOV

37 Extra-New Supremeness in Thinking Deconstructed dimensions and sting theories : The extra dimension emerges from the theory, is used to solve problems, and the theory comes back to the normal 4 dimensions serviced and healthy and with all the necessary Higgses. No tricks. (Arkani-Hamed et al, Hill et al…..)

38 If you ask questions about what happened at very early times, and you compute the answer, the answer is: Time doesn’t mean anything. S. Coleman Space and time may be doomed. E. Witten I am almost certain that space and time are illusions. N. Seiberg The notion of space-time is clearly something we’re going to have to give up. A. Strominger

39 The coming Invasions will answer (among many other questions) What happens to gravity at short distances? What is the physics that explains the enormous disparity between the gravitational scale and the scale of the typical mass of the elementary particles? Why does the cosmological constant have the value it has? What is dark energy and what is dark matter? What is the lifetime of the proton? What is string theory? What is the fundamental dynamics behind spacetime?

40 …for any important assertion evidence must be produced; …prophecies and bugaboos must be subjected to scrutiny; … guesswork must be replaced by exact count; ….accuracy is a virtue and inquiry is a moral imperative. To the hegemony of science we owe a feeling for which there is no name, but which is akin to the faith of the innocent that the truth will out and vindication will follow. In its purest form science is justice as well as reason. Jacques Barzun SCIENCE: The Glorious Entertainment