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What does the Muon g-2 experiment tell us?

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The Muon g-2 experiment announced one of the most tantalizing physics measurements in over a decade. It is possible that the measurement tells us that our theoretical calculation is missing some new physical phenomena. It is also possible that a new theoretical prediction points to the possibility that measurement and prediction basically agree. In this exciting video, Fermilab’s Dr. Don Lincoln gives you an insider’s perspective.

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May 26, 2021 at 10:16 pm

Posted in High Energy Physics

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A Cosmic Muon Observer Experiment for Students

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Overview of the CosMO setup in operation with three scintillator boxes (right), the DAQ card (center), and the readout netbook with the graphical user interface (left)

Overview of the CosMO setup in operation with three scintillator boxes (right), the DAQ card (center), and the
readout netbook with the graphical user interface (left)

CosMO – A Cosmic Muon Observer Experiment for Students
R. Franke, M. Holler, B. Kaminsky, T. Karg, H. Prokoph, A. Schönwald, C. Schwerdt, A. Stößl, M. Walter
What are cosmic particles and where do they come from? These are questions which are not only fascinating for scientists in astrophysics.
With the CosMO experiment (Cosmic Muon Observer) students can autonomously study these particles.
They can perform their own hands-on experiments to become familiar with modern scientific working methods and to obtain a direct insight into astroparticle physics.
In this contribution we present the experimental setup and possible measurements.
The detector consists of three scintillator boxes. Events are triggered and read out by a data acquisition board developed for the QuarkNet Project.
With a Python program running on a netbook under Linux, the trigger and data taking conditions can be defined. The program displays the particle rates in real-time and stores the data for offline analysis.
Possible student experiments are the measurement of cosmic particle rates dependent on the zenith angle, the distribution of geometrical size of particle showers, and the lifetime of muons.
Twenty CosMO detectors have been built at DESY.
They are used within the German outreach network Netzwerk Teilchenwelt at 15 astroparticle-research institutes and universities for project work with students.
Read more at http://arxiv.org/pdf/1309.3391v1.pdf

Written by physicsgg

September 16, 2013 at 9:43 am

Posted in ASTROPHYSICS

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Τhe muon

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Ιn 1900, shortly after the electron and radioactivity were discovered, Lord Kelvin famously remarked:

There is nothing new to be discovered in physics. All that remains is more and more precise measurement

He would be proved horribly wrong. The discovery of the nucleus and then its constituents, the proton and neutron, revolutionised our view of what the world was made of. Our understanding of the world changed from the classical to the quantum and up to 1933 quantum mechanics went from success to success in describing experimental observations. This culminated in the Dirac equation, which predicted the existence of anti-matter, confirmed shortly afterwards by the discovery of the anti-electron (the positron). However, the physicists’ smugness was short-lived. Behind the scenes, all was not well. Quantum Mechanics was struggling to provide an explanation for particles that were raining down on earth from the cosmos at a rate of 10,000 per minute per m2. A veritable who’s-who of physics luminaries were trying to understand the nature of these “cosmic-ray” particles. Since at that time the only known particles were electronsprotonsneutronsphotons and (yet to be directly detected) neutrinos. It was assumed that these cosmic-ray particles arriving at the earth were electrons.

The problem with this (wrong) assumption was that the “electrons” raining down on the earth seemed to come in two varieties –1. those which were easily absorbed by blocks of lead and which created a secondary shower of electrons, positrons and photons when they interacted with the lead and 2. those that penetrated the lead blocks with aplomb.
At first, quantum mechanics had no explanation for why electrons should behave in either of these ways, but gradually the theory was modified (notably by Bethe, Carlson, Heitler and Oppenheimer). They found a way to describe type 1 (the “electron” that showered in lead) but, alas, they had no such luck finding an explanation for the type 2 penetrating particles. Theoretical physicists (having enjoyed so much success up to then) were in despair. Oppenheimer, always a bloke for adding a bit of gravitas to the situation and who generally preferred his glass half empty, wrote to his brother in 1934:

Oppenheimer: nicotine fuelled Quantum Mechanics

As you undoubtedly know, theoretical physics – what with the haunting ghosts of neutrinos, the Copenhagen conviction, against all evidence, that cosmic rays are protons, Born’s absolutely unquantizable field theory, the divergence difficulties with the positron and the utter impossibility of making a rigorous calculation at all – is in a hell of a way

Quickly, the idea that the penetrating particles were protons was dismissed and the physics community was faced with a stark choice: a new particle or the acceptance that quantum mechanics was hopelessly flawed. For a time (now conveniently overlooked) they fudged the issue and started to speak sotto voce about the possibility of “red and green electrons” – one type being absorbed and the other penetrating….. Read the rest of this entry »

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May 14, 2011 at 1:32 pm

Posted in High Energy Physics

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