# Tag Info

0

Q^2 is the Mandelstam variable t, i.e. the four momentum transfer squared where the s channel is the x axis in the feynman diagram. where p1 p2 are incoming. In the same link it is seen that at the relativistic limit : The dot product for t (Q^2) is p transverse to the incoming beam direction of p1 , p2 are incoming. etc. Is this Q the same if ...

0

Typically, we solve a partial differential equation (analytically if we can, but often we can only do numerical calculations), where in the input of the problem we put the known quantities Physics started with observations of nature, and mathematics developed which could model the observations and measurements and predict future set ups. Beginning with ...

1

What are the properties of proton+proton fusion reaction $$p + p → 2H + e^+ + ν_e + 0.42 MeV$$ making it hard to replicate on Earth? This reaction has been replicated many times on Earth. The problem is that the reaction requires a proton to decay into a positron and a neutron at the instant the collision occurs. This is extremely unlikely. This is why, ...

1

The problem is that there is a huge potential barrier for the fusion of two protons due to their electrostatic repulsion, and this makes fusion an extremely low probability process. Even in the extreme conditions in the core of the Sun proton fusion is exceedingly slow - this is discussed in Why does the Sun's (or other stars') nuclear reaction not ...

3

The reaction has been studied in accelerators A bubble chamber study of proton-proton interactions at 4 GeV/c Part I—Elastic scattering, single-pion and deuteron production .Summary Elastic scattering, single-pion and deuteron production have been investigated. The cross-section for elastic scattering is σelastic = (13.5±0.3) mb. The angular ...

9

Fake event injection is only one of several schemes for "blind" analysis. Other blinding schemes involve manipulating some parameter of the data as show to the analysis team by a reversible transformation of some kind, multiple independent analyses, and complete analysis dry-runs on simulated data. The thing to understand is what purposes are served by ...

9

The LIGO experiment consists of detecting individual events with a characteristic form that take place in less than a second. Given the high stakes and that conceivably, only one or a few events might be detected, it made sense to have dry runs of thedetection protocol to assess it's reliability and fidelity. The LHC monitors millions of collisions per ...

32

Let me first mention that the LHC is in a way a text book experiment: you have a very good control over the experimental conditions and you can repeat your experiment as often as you like. You have, in way, full control over the signal. Results are reproducible in that you just redo the experiment. LIGO is "just" a detector: In particular, you have ...

52

After they told me about their impressive "LHC Olympics" in which physicists (often hardcore theorists) were reverse engineering a particle physics model from the raw (but fake) LHC data, I proposed the same idea in a circle of physicists at Harvard, including Nima Arkani-Hamed, sometime in 2005 and we have worked on that LHC ideas in some detail. We were ...

Top 50 recent answers are included