What are oblique parameters?

In context with electroweak precision tests, Peskin-Takeuchi or oblique or S,T,U parameters are quite familiar. I am looking for some references where these things are nicely explained (I have...

05 June 2018 4,061 0 View

What is 'bare mass' in context with particle physics?

05 June 2017 2,297 1 View

Why the sea quarks and gluons do not contribute to the vector current?

03 April 2017 3,218 11 View

Why Majorana fermions do not have vector currents?

Majorana fermions do not have vector interaction and hence there is no spin-independent direct search cross section for majorana like WIMPs. Can anyone please show me the proof ?

03 April 2017 5,435 3 View

What is the expression for Dark Matter (DM)-nucleon direct detection cross section?

For a Vector Boson DM, I have the following spin-independent direct detection (scattering) cross-section with nucleus (please see the attahced file), where n_n and n_p are the number of nucleons...

02 March 2017 3,944 4 View

How to calculate the annihilation cross section given a dark matter (DM) effective operator?

02 March 2017 3,138 4 View

What is H_T cut in connection with collider physics?

In collider physics I have frequently come across H_T cut over jet momenta. How do we define this quantity and what is the physical reason for applying this apart from missing energy cut?

01 February 2017 8,596 3 View

In 2 Higgs doublet model, how the gauge bosons get mass?

31 December 2016 981 8 View

What is the vertex factor for vector boson-scalar-scalar interaction?

I have a Feynman graph in t-channel with vector (X)-scalar(\phi)-scalar(\phi) vertex. Can someone please help me to find out what is the vertex factor for such a process and how can I calculate...

31 December 2016 7,536 4 View

Why the anti-commutation of gamma matrices give a flat metric?

We know that ${\gamma_{mu},\gamma_{nu}}$= 2 $g_{\mu\nu}$, where $g_{\mu\nu}$ is the flat metric . That shows spinors are someway related to the metric of space. Can anyone please explain how?

08 September 2016 9,765 3 View

Physics: Why do we describe light by referring to its wavelength, but microwaves and radar pulses by referring to their frequency?

In physics, the description of the properties of light generally refers to its wavelength (nm), while in the range of microwaves and radio waves we refer to the frequency of a signal (e.g. kHz or...

03 March 2021 1,682 3 View

Why are the velocities so high in my Boussinesq approximation Fluent simulation?

Hello, I have a mechanism where air rises due to convective flows. In this simulation, nothing is driving the air except this. I understand that the Boussinesq approximation only works for small...

02 March 2021 4,910 3 View

What is the characteristic length to determine the Reynolds number for the scattered turbulent fluid flow?

Dear all, I just saw this example in FB on the difference between laminar flow and turbulent flow. The flow from a pipe hits the sink and scattered. The flow from the pipe is characterized as...

02 March 2021 1,999 5 View

Why almost every element would be metallized in sufficiently high pressure and low temperature?

(This statement is from wikipedia, BTW). What is so special about metallic bond that is limiting high-P low-T state of a matter (as long as individual atoms exist, not white dwarf of neutron star...

02 March 2021 3,309 2 View

Discrete Phase model (DPM) particle break-up has particle size limits during particle tracking?

Hello, I am currently working on simulating water droplet partciles in a closed room. When I use uniform particles, without "particle break-up", I can carry out the simulation without any problem....

02 March 2021 3,053 2 View

How Relativistic effects is one reason for lanthanide contraction?

The Lanthanide contraction which is the decrease in ionic radii of the elements in the lanthanide series from atomic number 57, lanthanum, to 71, lutetium, is due to poor shielding of the 4f...

01 March 2021 2,272 4 View

Distribution of particles in metal matrix?

How would define the "good" and "poor" distribution of particles within the matrix. Is there a quantitative solution to assess the distribution of the particles, which then having denotation of...

28 February 2021 7,397 8 View

What is the density for pva electrospining?

I'm Juan Carlos, a high school student who is working with electropinning, I made an electropinning machine with a 21g needle and a 30kv high voltage source and the distance between my needle is...

28 February 2021 298 3 View

Is there a deep reason for using the squared modulus of the wave function as the probability density of the existence of the particle?

I think we were all surprised at the first time we got to know quantum mechanics that the squared modulus of the wave function is the probability density of the existence of the particle? The role...

28 February 2021 6,282 9 View

Should we reduce the standard unit of length to 0.31951540592 meter ?

The reasoning behind this question is to align the ratios of the proton potential in energy per charge to the speed of light in distance per time. As these two dimensions appear to be related,...

27 February 2021 947 7 View