Electro not-so-weak interactions Paolo Ciafaloni INFN – Sezione di Lecce

In this talk What is the asymptotic behaviour of cross sections What is the relevance for LHC, LC? Standard Model of EW int. E>>Mw,Mz,mt~M~100 GeV Only relevant scale for the process

How the story begins on a day of last century......

RGE 1 loop Why not RGE-driven? σ10 TeV higher orders LEP: leading terms in m t, (log E)

At high energies Z,W similar to g, At high energies Z,W similar to g, P. Ciafaloni, D. Comelli 98 Singularity for k 0, k ~ p log 2 μ (EW: μ M) Asymptotic behaviour dictated by IR (not UV) Emission probability ~ log 2 (E/M) (non ) p p+k k

Asymptotic expansion IRUV LHC, LC LEP n loops: Unusual situation! QED, QCD (α log) Dependence on IR cutoff M for any E LLNLLNNLL

2 fermions B. Jantzen V.A. Smirnov hep-ph/ loops SU(2)

S. Moretti, M. Nolten, D. Ross, hep-ph/

Inclusive observables P P 2 j + X W,Z X hard: E > 1 TeV soft: 100 GeV < E << 1 TeV

BN: IR safe observables do not exist! QED BN : EW BN: all observables, even including W, Z emission depend on P. Ciafaloni M. Ciafaloni D. Comelli

Noncancellation mechanism QCD confines color average infrared safe ! EW: average over e, senseless Symmetry breaking BN M. Ciafaloni, P. Ciafaloni, D. Comelli

E asymptotically

A 1 TeV 14 % 8 % P. Ciafaloni M. Ciafaloni D. Comelli 05

U. Baur (2006)

as a function of inclusivity x

Heavy quarks production P. Ciafaloni, D. Comelli 06

Conclusions Why dont we begin taking seriously into account weak gauge bosons emissions at ILC, LHC?

Conclusions High energy EW dominated by log^2(E) of IR origin W,Z emission HAVE to be considered for ILC but also for LHC Final prediction (sign) very much dependent on observable definition

Correzioni elettrodeboli alla scala del TeV Precisione < 1% higher orders 1 loop, leading 2 loops, risommazioni predizioni sotto controllo Precisione inferiore Non necessariamente dominato da QCD Osservabili inclusive effetti spettacolari - Dominate da struttura IR, non UV - O(20 %) a 1 TeV