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This lecture delves into the Higgs boson and its pivotal role in the Standard Model of particle physics. It reviews ongoing challenges, such as the limitations of the Standard Model, and discusses proposed solutions like supersymmetry and grand unified theories. The speculation strategy is analyzed, focusing on methods to localize particles and the search for evidence of new physics beyond the current model. The excitement around potential Higgs discovery and the implications for our understanding of fundamental forces in nature are also highlighted.
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FK7003 Lecture 15 – Next steps • The Higgs boson • Review of the Standard Model • Problems of the Standard Model • Proposed Solutions
FK7003 The Standard Model
FK7003 The Higgs boson
FK7003 How do we look for the Higgs ? Production mechanism Dominant decay b b b
FK7003 Have we already found it ? Lots of excitement around 2000/2001 as LEP reached the end of its life.
FK7003 Observation of a Higgs ? An excess of events was seen at mass 115 GeV but reanalysis of data and rigorous statistical calculation of significance means it is impossible (and stupid) to conclude a Higgs was seen. Lower mass limitMH > 113.5 GeV (15.02)
FK7003 Been here before - top quark non-discovery… • 1984 CERN • UA1 experiment • pp (630 GeV cm energy) • Something they would rather forget
FK7003 Race for the Higgs
FK7003 Where is the Higgs ?
How good is the Standard Model ? * The focus of the rest of this lecture FK7003
FK7003 Speculation strategy
FK7003 How well can we localise a particle ?
FK7003 Compton Wavelength
FK7003 Gravity
FK7003 Question
FK7003 Other possible energy scales 1/coupling Electromagnetic E measurements Weak GUT scale Strong Log(Momentum transfer, Q(GeV) )
FK7003 Speculation strategy
FK7003 Problems of the Standard Model
FK7003 Supersymmetry (15.07)
FK7003 Why look for SUSY ? Standard Model Standard Model+SUSY 1/coupling 1/coupling Electromagnetic E Electromagnetic Weak Weak Strong Strong Log(Momentum transfer, Q(GeV) ) Log(Momentum transfer, Q(GeV) )
FK7003 Grand Unified Theories
FK7003 Extra spatial dimensions
FK7003 Micro Black Holes at the LHC
FK7003 Electric charge quantisation
Maxwell’s equations FK7003
FK7003 Monopoles and charge quantisation z P qm q d qe x
FK7003 Q
FK7003 Dirac’s quantisation condition z P qm q d qe x
FK7003 Speculation strategy
FK7003 So how close are we to a unified theory of all the forces ?
FK7003 Summary • Higgs discovery would be confirmation of the Standard Model • Standard Model is incomplete • A range of proposed solutions exist which postulate the existence of ”new” particles which could be ”around the corner” at LHC energies.