On Monday, May 27, 2019 at 6:41:39 AM UTC-5, Bruno Marchal wrote:
>
>
> On 24 May 2019, at 02:26, Lawrence Crowell <[email protected] 
> <javascript:>> wrote:
>
> On Thursday, May 23, 2019 at 11:03:49 AM UTC-5, howardmarks wrote:
>>
>> Good point on the "Higgs" Boson. Especially when the discoverer said what 
>> he said. The experiments at CERN, Fermi Lab, etc. were run with the 
>> standard model in mind. They defined the "evidence" they expected a Higgs 
>> boson to manifest in residue particles, and, when they found, amongst the 
>> subatomic and atomic debris, a particle near the characteristics they 
>> expected, they called it a "hit".  There is only indirect evidence. We 
>> can't directly observe picometer objects moving at close to the speed of 
>> light. We know few things, like the mass to charge ratio and approx kinetic 
>> energy...  
>> Cheers!
>>
>
> My area is physics, and have written on the connection between spacetime 
> or gravitation with particle physics. Cosmin wanted to see the Higgs boson, 
> and that is about it. It may be disappointing, but the particle only last 
> about 10^{-25} seconds on a path 10^{-15}cm long. So we detect this field 
> by the particles it decays into. Since it requires a lot of energy the 
> machine is large, the detectors are large and it is a major undertaking. I 
> don't have Higgs particles in my pocket.
>
>
> Really? How does your handkerchief get a mass? 
>
> Bruno
>
>
The mass of particle is due to the coupling of three of the Goldstone 
bosons in the two doublets. The Higgs particle detected does not couple to 
anything, so again I do not have a Higgs boson.

The two doublets (H^+, H^-) and (H^0, h) for the charged weak currents and 
the neutral weak currents couple as

W^± + H^± → WH^±

Z^0 + H^0 → ZH^0

where the condensate physics of the Higgs Goldstone bosons on the left 
results in the charge and neutral currents on the left that have mass. The 
weak interaction currents on the left have transverse field components, but 
since they are massive there is no longitudinal field component. On the 
right however the weak interaction field components have longitudinal 
fields, where the degree of freedom of the Higgs Goldstone bosons are 
transferred into these longitudinal components. A lot of physics is about 
counting degrees of freedom.

There are the Yukawa Lagrangians L_y ~ g_yψ-bar Hψ that give small masses 
to quarks and leptons. For low mass particles this is a few MeV, say the 
electron and ud quarks. It is tiny for neutrinos, which actually leads to 
big questions, and it approaches the mass of the Higgs particle for the top 
quark. However, most mass is in baryons due not to the Higgs condensate but 
due to the the self-confinement of the QCD interaction. 

So the Higgs particle measured by the LHC is this loner particle h, which 
in this theory does not couple to anything. One could imagine a theory 
where this does couple to the photon, which would break the U(1) symmetry 
of quantum electrodynamics (QED). However, in standard EW physics that does 
not happen. Curiously though, superconductivity is a case where QED is 
symmetry broken, and there have been proposals for saying this lone Higgs 
particle defines condensate states in the vacuum that are responsible for 
U(1) breaking of QED and superconductivity. Yet, if this particle is 
produced at high energy it rapidly decays into two Zs, a W++ and W^- or two 
photons. These diphoton decays, which the Zs and Ws decay into as well, are 
the target of LHC Higgs detection.

LC

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