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The 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions

The 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions June 16 - 21, 2008 Seoul, Korea. String Physics at the LHC. ATLAS. ALICE. CMS. Luis Anchordoqui. Outline. ✻ String theory and all that. ✻ Extra U (1)´s in D-brane constructions.

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The 16th International Conference on Supersymmetry and the Unification of Fundamental Interactions

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  1. The 16th International Conference on Supersymmetryand the Unification of Fundamental Interactions June 16 - 21, 2008Seoul, Korea

  2. String Physics at the LHC ATLAS ALICE CMS Luis Anchordoqui

  3. Outline ✻ String theory and all that ✻ Extra U (1)´s in D-brane constructions ✻ Photons and gluons as quiver neighbors ✻ LHC discovery reach ➣Works done in colaboration with Haim Goldberg, Satoshi Nawata and Tom Taylor PRL100, 171603 (2008) arXiv:0712.0386; arXiv:0804.2013

  4. TeV Scale Strings ➣ Large extra spatial dimensions and D-brane constructs allow low string scale compatible with weak 4-D gravity Regge recurrences in TeV region Antoniadis, Arkani-Hamed, Dimopoulos and Dvali PLB436, 257 (1998) ➣Open strings can terminate on stack of N identical D branes U(N) gauge group for each stack Polchinski PRL75, 4724 (1995)

  5. Gauge Fields ￭ U(3) : 8 SU(3) gluons, additional U(1) ￫ C μ coupled to baryon number ￭ U(2) : 3 SU(2) W´s, additional U(1) ￫ X μ Antoniadis, Kiritsis and Tomaras PLB486, 186 (2000) ￭MinimalSp(1) : 3 W´s,no additional U(1) Berenstein and Pinansky PRD75, 095009 (2007) ￭ U(1) : another extra U(1) ￫ B μ Y (hypercharge) = linear comb of C , X , B μ μ μ μ Conversely

  6. Minimal Quiver Standard Model Berenstein and Pinansky PRD75, 095009 (2007)

  7. gg → g g ￭Does not exist at tree level in field theory ￭But does exist at ¨tree¨ (i.e. disk) level in string theory ￭Involves only gauge bosons so is independent of the fermion embeddings ￭Idea is that

  8. Amplitudes The basic string partial amplitude is (MHV, or Maximum Helicity Violating) Veneziano form factor Parke and Taylor PRL56, 2459 (1986)Stieberger and Taylor PRL97, 211601 (2006)

  9. Squared Average Now permute, square,sum,averageandprojectonto photon: ● ● ●

  10. Limiting Cases At low energiess, t, u « M² s ❖ Note that (unwanted) zero mass poles have cancelled –not trivial!Usually implemented by hand through choice of Chan- Paton factor❖ Burikham, Figy and Han PRD71, 016005 (2005) Cheung and Liu PRD72, 015010 (2005) Meade and Randall JHEP0805, 003 (2008) See, however, Cullen, Perelstein and Peskin PRD62, 055012 (2000) Near string threshold s ≈ M² s Scattering proceeds through J = 0 and J = 2 angular momenta

  11. Phenomenology ￭ At collider resonance formation and decay will populate high k region T ￭ SM processes for pp→ g + jet -5 Lead to rapid ~ kfalloff T ￭ Take as our signal N above SM background for integrated cross section ev

  12. vs.k T,min

  13. σvs.M s

  14. Isolated prompt photons Gupta, Choudhary, Chatterji, Bhattacharya and Shivpuri arXiv:0705.2740 Major experimental background misidentification with high k πº- O (10³) multiplier T Imposition of isolation cuts reduces event rate for the high kπº background T

  15. β 5 QCD background from direct photon production ≈ 8.1 x 10 (for 100 fbˉ¹) Introducing Increases effective background by factor ￫ Decreases S/N ratio by

  16. Bump-hunting ￭ Hope to see resonance bumps in data binned inM =invariant mass of  + jet ￭ Impose rapidity (y) and kcuts on photon and jet and measure cumulative cross sections T ￭ Look for regions with significant deviations from QCD background, find interval with bump! ￭ Integrate over [M - 2, M + 2] find S/N s s

  17. Signal-to-Noise

  18. Discovery Reach

  19. ALICE ￭Wemaysimultaneously compare thecollidingPbPbfacilitywiththeprotonbeamforoursearch ￭Ignore parton shadowing, assume ￭Flux greaterby factor of A energy/partonlessby factor of Z/A ≃0.3

  20. ALICE Sensitivity requires pbˉ¹￫ above present day estimate of integrated luminosity

  21. Remarks and Conclusions ✻Wehaveidentified a tree-levelprocessuniquetostrings, independent of embedding ✻Discovery of TeV-scale string physics (at 5) possible for M ~ 2.3TeV with 10% C-Y mixing s ✻Results are conservative in that ● stringcorrectionsto SM processesnotincluded ●contributionfromtails of higherresonancesnotincluded ✻High-k Z production suppressed relative to ’s by a factor of tan²θ = 0.3 differs radically from evaporation of black holes produced at the LHC T W

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