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Monopoles. The Mystery. At the beginning there was Maxwell. Vacuum. Symmetry under electromagnetic duality. MAXWELL. Matter (Source). Duality Symmetry is explicitly Broken In order to restore symmetry is necessary to introduce Magnetic charge(MONOPOLE) and the magnetic current.
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Monopoles The Mystery
At the beginning there wasMaxwell... Vacuum Symmetry under electromagnetic duality
MAXWELL Matter (Source) Duality Symmetry is explicitly Broken In order to restore symmetry is necessary to introduce Magnetic charge(MONOPOLE) and the magnetic current
With this transformation Duality Symmetry is restored in Classical Electromagnetism The Price to be pay is the introduction of MONOPOLE
The following step, Dirac...(1931-1934) Monopole with Quatum Mechanics Schrodinger equation for a particule moving in the electromagnetic fields Invariance under Gauge Transformation
Magnetic Monopole ₊g ∞ Singularity
THE SEARCH Monopoles of the usual Grand Unification havemasses of theorder m > Could only be produced in the first instants of the Universe and only searchable in cosmic radiation Big Bang predicts 1000 monopoles per nucleon (disagreement with observation = no one observed) The paradox is solved by Inflationary Cosmological Models, that greatily reduced the monopole density
Monopole Searches in Accelarators No Dirac prediction for monopole mass “Lower Bound” using classical electron radius by analogy: Assuming:
Search of Monopole in Accelerators Direct Searches ⇒ Monopole production as free particles Going from lepton production we replace Two photon s=1/2 e gβ Drell-Yan
The experimental limits on monopole mass The most recent limits on the monopole mass HERA e+ p – collisions |n|=1,2,3,6 Tevatron p p – collisions Experiment E-882 (Al) |n|=1, M > 285 GeV (Al)|n|=2, M > 355 GeV (Be) |n|=3, M > 325 GeV (Be) |n|=6, M > 420 GeV LEP 2 e+ e-– collisions (Al) M > 140 GeV 45 ≤ M < 102 GeV
BOUND STATE MONOPOLE ANTIMONOPOLE DIRAC DIXIT: (1934) “…THE ATTRACTIVE FORCE BETWEEN TWO MAGNETIC POLES IS 4692 TIME THAT BETWEEN THE ELECTRON AND THE PROTON. THIS VERY LARGE FORCE MAY PERHAPS ACCOUNT FOR WHY THE MONOPOLES HAVE NEVER BEEN SEPARATED …” MONOPOLIUM
Monopolium Dynamics Monopolium production from photon fusion Nonrelativistic bound state Attributed to beam width aprox. 10 G eV
Monopolium Decay Monopolium Vertex Monopolium production and Decay
Analysis of p-p scattering Processes above the monopole Threshold M M M
Evaluation Energy Diferential Cross Section Elastic Scatering Elastic photon spectrum Elementary photon-photon cross section =C.M energy pp system = C.M energy of the photons This procedure can be generalized easily to semi-elstic and inelastic case
Cross section monopole antimonopole annhilation Compararison Higgs and monopole antimonopole decay
Fixed binding energy 100GeV
Monopolium Cross Section Total Semi-elastic Elastic Inelastic
Concluding Remarks Dirac felt that he ¨would be surprised If Nature had made no use for it. It, being the Magnetic Monopole¨. Ed Witten once asserted in his Loeb Lecture at Harvard, ¨almost all theoretical physicists believe in the existence of magnetic monopoles, or at least hope that is one¨. Joshep Polchinsky, a string – theorist, described the existence of monopoles as ¨one of the safest bets that one can make about physics not yet seen¨ and that ¨their existence seems inevitable in any framework that explains the quantization of electric charge. Of course their mass scale and abundance are highly uncertain,… ¨
CONCLUSIONS • Monopoles are hypothetical, but predicted by the most major theoretical models • No confirmed repeatable monopole events have been recorded • Strong lower limits on energy probably place Dirac monopoles on the reach of colliders • Strong upper limits on cosmic ray flux • Maybe finding reasons to their inexistence is more interesting than finding them?