Recent content by Daaavde

I see, thank you very much. I was just puzzled by the KATRIN experiment. They claim that they would potentially see a drop-off at the neutrino mass, however that confuses me. Since the neutrino potentially carries the three masses eigenvalues, wouldn't they rather see (hypothetical infinite...

Hello everyone! I've a question regarding the neutrino masses. When neutrinos interact they must do so in a specific flavour (e.g. e, μ,τ) and if we go to find out what their flavour is at the interaction we get a specific answer. However, it is not clear to me what we would find out if we...

My uncertainties are systematic and statistical uncertainties on datapoints representing the flux of cosmic protons as a function of energy. The systematic uncertainties come from different factors related to the detector, resolution and MC. I'm currently performing a global fit including...

I thought about picking the uncertainty that applies to the different cases (lower uncertainty if fit lower than data point or viceversa), but the problem is that I'm running the covariance matrix in a minimizer to find the best fit parameters for my test formula. Currently I'm generating my...

Hello everyone, I'm currently building the covariance matrix of a large dataset in order to calculate the Chi-Squared. The covariance matrix has this form: \begin{bmatrix} \sigma^2_{1, stat} + \sigma^2_{1, syst} & \rho_{12} \sigma_{1,syst} \sigma_{2, syst} & ... \\ \rho_{12} \sigma_{1,syst}...

Sorry, I can't see how that answers the question. There are no time derivatives here or maybe I overlooked something.

So, I should prove that: - \frac{\partial H}{\partial q_i} = \dot{p_i} And it is shown that: - \frac{\partial H}{\partial q_i} = - p_j \frac{\partial \dot{q_j}}{\partial q_i} + \frac{\partial \dot{q_j}}{\partial q_i} \frac{\partial L}{\partial \dot{q_j}} + \frac{\partial L}{\partial q_i} =...

From "Martin & Shaw", regarding problem 3.5 (sometimes it uses natural units "c=1"): "The particle has \gamma = E/m \approx 10, hence \tau \approx c (?) and the average distance is d \approx c \gamma \tau \approx 3 \times 10^{-14}m if we assume a lifetime for the particle at rest of 10^{-23}."...

Thank you for the answer!

Hello to everyone, I got a little bit confused between the coupling constant g_W and the strength parameter \alpha_W in the weak interaction. For what I know they should both give an idea of the strength of the interaction but I miss to understand what's the difference between them.

I'm sorry, but something is missing for me. If we expand, we get: \sqrt{m^2 + p^2} + m \frac{2m}{2\sqrt{m^2 + p^2}} and considering p>>m: p + \frac{m^2}{p} So, I'm missing the factor 2 next to p.

I'm stucked in a passage of Particle Physics (Martin B., Shaw G.) in page 41 regarding neutrino oscillations. Having defined E_i and E_j as the energies of the eigenstates \nu_i and \nu_j, we have: E_i - E_j = \sqrt{m^2_i - p^2} - \sqrt{m^2_j - p^2} \approx \frac{m^2_i - m^2_j}{2p} It...

I thought about this but i wasn't sure. This means that an unpolished surface gets warmer than a polished one?

AndyResnick: Unfortunately not, I only know the samples were generally roughened but I think there was no contamination present. The instrument (coated in Spectralon) has been correctly calibrated. The data from polished copper (and other metals) are just theoretical. UltrafastPED: I'm sorry, i...

Hello, I would like to ask why, when a surface is not polished, it reflects less. I understand that when the surface is not polished, microscopically it presents a lot of irregularities so that when the light strikes the surface it gets reflected in all directions and instead of getting...