What Are the Key Differences Between MET and MPT in Particle Physics?

[ges87]

Hello, I was reading some articles about the ADD model, and I had a few questions about them:

1)Wht's the difference between missing transverse energy and missing transverse momentum? I suppose one of the 2 is the opposite of the vector sum of the transverse momenta of all the detected particles, and corresponds to the vector sum of the transverse momenta of all the undetected particles, but the other one?

2)I read articles about monojet and di-jet analysis that are used to calculate bounds on the parameters of the theory, but there are also some other experiments that can be usefull to find bounds? Or those two experiments are the most useful? if yes, why? for example, what about PP->2 photons? or fermion+antifermion->2 photons or 2fermions->2fermions scattering?

 

[AndyW]

Hello,

Thank you for your questions about the ADD model. I am a scientist in the field of particle physics and I would be happy to provide some clarification on the concepts you mentioned.

1) Missing transverse energy (MET) and missing transverse momentum (MPT) are both measures of energy and momentum that cannot be accounted for by detected particles in an event. However, they have slightly different definitions and interpretations.

MET is the magnitude of the vector sum of all the transverse momenta of undetected particles in an event. It is often used in experiments that involve the detection of invisible particles, such as neutrinos or dark matter particles. MET can also be used to search for new particles that escape the detector without leaving a trace.

On the other hand, MPT is the opposite of the vector sum of the transverse momenta of all the detected particles in an event. It is often used in experiments that involve the detection of new, heavy particles that decay into known particles. By measuring MPT, scientists can infer the presence of these new particles and their properties.

2) The monojet and di-jet analyses are indeed some of the most useful experiments in the search for new physics inspired by the ADD model. However, there are also other experiments that can provide useful bounds on the parameters of the theory.

For example, the production of two photons (PP->2 photons) can also be used to search for new particles that decay into photons. This process is particularly sensitive to particles with electric charge, such as supersymmetric particles.

Similarly, fermion+antifermion->2 photons or 2fermions->2fermions scattering can also be used to probe for new particles. These processes are sensitive to particles that interact strongly with fermions, such as the top quark or the Higgs boson.

In summary, while the monojet and di-jet analyses are important in the search for new physics, other experiments can also provide valuable information and contribute to the overall understanding of the ADD model. The choice of which experiments to use depends on the specific signatures and properties of the new particles being searched for.

I hope this helps to answer your questions. If you have any further inquiries, please feel free to ask. Thank you for your interest in the ADD model and particle physics.