[General] light light interactions

[Roychoudhuri, Chandra]

Hello Everybody:
I have again looked at the original ATLAS publication. The experiment is a very high energy non-linear phenomenon in the vicinity of highly charged Pb-atoms. As an experimental physicist in the field of optical sciences, I do not find the experiment as generalizable to state “light-by-light scattering” phenomenon. The scattering of high energy Gamma-Gamma wave packets, still in the vicinity of highly-charged, high energy Pb-nuclei, should not be generalized to incorporate the entire band of EM radiation, from radio, to micro, to visible, to X-ray wave packets. [See below the reference to the original paper.]

I do find it sad that the title of the paper uses generalized expression “Evidence for light-by-light scattering…”; instead of calling out that it is a very high energy complex phenomenon. It is susceptible to subjective interpretations of the theory since the interaction of the parameters are quite complex, which are not yet all quantified very well.
In the process, we are pro-actively weakening the platform of “Evidence based science”, which has very serious long-term re-percussions for the entire scientific enterprise.

Of course, the technical content of the paper is scientifically beyond criticism. But, in the age, when the most powerful country is trying to run the world by “twit-headlines”; we need to be a lot more thoughtful!

Chandra.

https://www.nature.com/nphys/journal/vaop/ncurrent/pdf/nphys4208.pdf

Evidence for light-by-light scattering in heavy-ion
collisions with the ATLAS detector at the LHC
ATLAS Collaboration†
Light-by-light scattering (  !  ) is a quantum-mechanical process that is forbidden in the classical theory of
electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths
generated by ultra-relativistic colliding lead ions. Using 480 _b􀀀1 of lead–lead collision data recorded at a centre-of-mass
energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13
candidate events were observed with an expected background of 2.6 _ 0.7 events. After background subtraction and analysis
corrections, the fiducial cross-section of the process PbCPb (  )!Pb._/CPb(_)  , for photon transverse energy ET>3 GeV,
photon absolute pseudorapidity j_j<2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower
than 2 GeV and diphoton acoplanarity below

From: General [mailto:general-bounces+chandra.roychoudhuri=uconn.edu at lists.natureoflightandparticles.org] On Behalf Of Andrew Meulenberg
Sent: Sunday, August 27, 2017 10:39 AM
To: Nature of Light and Particles - General Discussion <general at lists.natureoflightandparticles.org>; Andrew Meulenberg <mules333 at gmail.com>
Cc: robert hudgins <hudginswr at msn.com>
Subject: [General] light light interactions

For those who argue against light-light interactions

http://physicsworld.com/cws/article/news/2017/aug/18/light-is-seen-to-scatter-off-light
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