for questions about design, process, data, or analysis of experiments and observations.

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28
votes
2answers
366 views

experimental bounds on spacetime torsion

Did Gravity Probe B provide any bounds on Einstein-Cartan torsion? is a non-zero torsion value at odds with the results regarding frame-dragging and geodetic effects?
5
votes
6answers
6k views

How to guess the correct fitting function to some data?

Imagine we are plotting some date points $\left(x_i,f(x_i)\right)$ that we obtained experimentally, and that we want to know what $f(x)$ is. The way to do this is to use some software and try to fit ...
9
votes
3answers
3k views

Why do neutrino oscillations imply nonzero neutrino masses?

Neutrinos can pass from one family to another (that is, change in flavor) in a process known as neutrino oscillation. The oscillation between the different families occurs randomly, and the likelihood ...
5
votes
1answer
1k views

What's jet multiplicity?

That's a basic thing, but, surprisingly, it is very difficult to find concise explanation of: What is the definition of jet multiplicity? Why is it interesting?
3
votes
2answers
322 views

What is the highest accuracy of measuring time differences achievable today?

I was wondering if it would be possible to shorten the distance between detectors when measuring the speed of neutrinos to, say, 7m rather than the current ~700km? In this way the distance traveled ...
12
votes
5answers
13k views

How do you determine power flow direction in a transmission line?

Below is a picture of a typical transmission line(about 200 kV). Is there a simple physics experiment which can be performed safely near the line, to determine the power flow direction. Or in other ...
10
votes
3answers
428 views

Reproducing the OPERA result

Are there any other facilities that would be capable of independantly verifying the opera result? In other words, a completely different source/detector for $\nu_{\mu}$ beams? Alternatively, there ...
0
votes
1answer
103 views

OPERA. Dates of figure 10

What are the real dates that are represented in the figure 10, page 17, in the OpERA paper Imo the X axis labels are inconclusive, or absent. (in the investigation of a crime it is relevant ...
13
votes
1answer
411 views

How are neutrino beams emitted at CERN?

As far I know they come from accelerator collisions, but I have read confusing things like magnetically focused. How could neutrinos be guided magnetically if they aren't affected by the ...
10
votes
2answers
150 views

ATLAS Higgs Interpretation

I came across this abstract, and I am curious as to what the ATLAS Team has actually discovered: Abstract Motivated by the result of the Higgs boson candidates at LEP with a mass of about 115~GeV/...
1
vote
0answers
66 views

What is the variable plotted on the y-axis on these Higgs exclusion graphs? [duplicate]

Possible Duplicate: Particle physics plots I have seen graphs like this in lots of talks by phenomenologists talking about the Higgs search (see for example FIG 3 in this paper or this blog ...
12
votes
1answer
275 views

Cleaning Already Mounted Microspheres on an AFM

I am running an experiment that uses a microsphere (Diameter ~ 50um) mounted onto the end of an AFM cantilever. I run several experiments in a row, but somewhere during a sequence, the microsphere ...
7
votes
4answers
828 views

Experimental evidence for parallel universes/multiverses

My idea of physics is that it is a collection of mathematical laws relating observables. And that one can perform alot of mathematical derivations on these laws to produce new laws between observables....
12
votes
2answers
434 views

Is there a way to directly observe the spin texture of the surface states of topological insulators?

Is there a way to directly, here I means in real space, observe the interaction of the surface states of 3D topological insulators with defects (dopings and adatoms)? How to observe the spin texture ...
1
vote
1answer
815 views

Estimation of accuracy of measurements?

When stating an estimation of the accuracy of my measurements (of electric current, in this case) would I state that it is equal to the residual error, or the limit of reading? (in this case, ±0.2 or ±...
10
votes
1answer
676 views

What makes us think we can actually detect gravitational waves?

This refers to the discussion about gravitational waves for the YouTube video LIGO Gravitational Wave Observatory. I have two questions: When the gravitational wave passes through the space where ...
17
votes
5answers
20k views

How was Avogadro's number first determined?

I read on Wikipedia how the numerical value of Avogadro's number can be found by doing an experiment, provided you have the numerical value of Faraday's constant; but it seems to me that Faraday's ...
2
votes
2answers
598 views

If LHC is the most powerful microscope in the world, what does it magnify?

Some experts (and non experts) have called LHC the most powerful microscope in the world. I am wondering, what does the LHC magnify? Or is calling it a microscope just wrong and misleading?
7
votes
3answers
3k views

Left and Right-handed fermions

Is there a simple intuitive way to understand the difference between left-handed and right-handed fermions (electrons say)? How to experimentally distinguish between them?
11
votes
4answers
542 views

How do we know that the nucleus isn't a quark-gluon plasma?

The standard picture of the nucleus of atom is that is several distinct nucleons, which themselves are composed of quarks. However, it seems to me like a much simpler picture is that the nucleus is ...
7
votes
1answer
974 views

What does “tagging” mean in experimental high energy physics?

Could someone explain in details the meaning of the terminology "tagging" in experimental high energy physics and how is it used in the analysis?
10
votes
2answers
2k views

How are Monte Carlo simulations used in experimental high energy physics?

How are Monte Carlo simulations used in experimental high energy physics? Particularly in studying detectors limitations (efficiencies?) and data analysis. I will appreciate giving a simple example ...
3
votes
1answer
792 views

Fitting to a high density scatter plot

I am trying to do a crude particle identification, using a Bethe Bloch tenchnique. Here is a plot I made from the data that I have From what I've read, the standard method to identify charged ...
5
votes
2answers
516 views

How are the HEP experiments' invariant mass plots generated?

I am experimenting and playing around with some data, and I'm having trouble seeing how to generate invariant mass plots. The data I have has a bunch of events, and variables such as $P,P_T,\eta,\phi$...
7
votes
1answer
909 views

How to prepare a desired quantum state?

Given a quantum state function, we can Fourier expand it in terms of stationary states of the Hamiltonian. So if we want to build that same quantum state approximately all we need to do is to ...
2
votes
1answer
148 views

Measuring concentration

I am trying to measure the concentration of a Volatile Organic Compound (VOC) inside a liquid using Gas Chromatography (GC). The liquid contains particles that cannot be sent to a GC, so I am using ...
5
votes
2answers
1k views

What is meant by “combinatorial background” in experimental high energy physics

My guess is that they find a certain tracks coming from a certain source by "combintaorially" selecting all track pairs and finding their invariant mass. If this is true, of which I am not sure, how ...
6
votes
1answer
190 views

Recent news about Tokamak

I first heard about the Tokamak in highschool 10 years ago and was wondering how far the technology has come since then. Can it sustain a reaction for more than a few seconds? Are these devices ...
4
votes
2answers
1k views

How Can We Measure The Mass Of Particle?

As we know, the mass of well known particles are below. $m_{n}\approx0.0000000000000000000000000016749286[kg]$ $m_{p}\approx0.0000000000000000000000000016726231[kg]$ $m_{e}\approx0....
13
votes
1answer
1k views

How to determine the mass of a quark?

As far as I know quarks are never found in isolation, so how can we determine their rest mass?
3
votes
1answer
288 views

Coincidence detectors in Bell tests: How close is close enough?

When is a coincidence a coincidence? We know that to identify entangled photons, the electronics is set to look for simultaneous clicks at opposite detectors. The size of the window is to some degree ...
3
votes
0answers
26 views

Review of Gas Chromatographs?

Could anyone suggest a recent review article or book on gas chromatography instrumentation? My interest is in the devices themselves, rather than using them for a particular application. This article,...
8
votes
2answers
259 views

How to predict how much data to collect

The same question on CrossValidated Apologies if I'm being a bit vague in what follows, I've been asked to keep certain aspects of the experiment confidential for the time being. An analogous ...
4
votes
2answers
602 views

What are the easiest to get/make LN2 superconductors?

I am starting to build multistage Peltier cooler at the moment, and it should be able to reach -100C at least (but if I fail I can always get boring LN2). Doing some experiments with superconductors ...
1
vote
1answer
288 views

Changing the capacitance of an object to trigger a capacitive touchscreen [closed]

I'm trying to trigger a human touch in a capacitive touchscreen without the 'human' part. I've noticed that the negative pole of a battery triggers it if you are currently holding it. Or if you use ...
-2
votes
1answer
225 views

muon neutrino momentum distribution

muon neutrino momentum distribution I have read the public data of T2K ,KEK to find this subject, I'm curiously that it's coincides with my prediction perfectly: The neutrino get its momemtum by its ...
3
votes
2answers
723 views

The most price-efficient experimental setup involving SPDC, single-photon counting etc

I would like a suggestion on a price-efficient way of experimenting with spontaneous down-conversion and single-photon counting. The simple dual-slit experiment could be one part of an application ...
2
votes
2answers
240 views

Reference for solid state particle detector

I'm looking for a good introductory text on solid state devices for particle detection.
12
votes
2answers
31 views

Why are binary objects so critical to astronomy?

There are a lot of astronomical objects out there to study but binary objects seem to get more attention. Why is this? What makes binary objects (stars, Kuiper Belt Objects, black holes, galaxies, ...
2
votes
2answers
3k views

How do you calculate the intensity of light around the focal point from a focused collimated beam of light?

Problem/Purpose of me asking this question to you people who know more than me: So I'm doing a science project where I'm collimating a beam of light to a focus point in a light medium (water vapor or ...
5
votes
0answers
357 views

Derivation of the oil drop experiment [closed]

The oil drop experiment performed by Robert Millikan in 1909 enables us to calculate the elementary charge. The following forces have effect on the droplet: $F_\mathrm{G} = m g = \frac{4}{3} \, \pi ...
5
votes
1answer
809 views

How does spring constant change with resistivity changes

I want to create a set of silicon based materials that have been doped with different materials and/or different amounts of dopants. The purpose of this is to see how the spring constant of silicon ...
1
vote
2answers
263 views

self-antiparticles and broken symmetries

certain particles (i.e: certain bosons like the photon) do not have an anti-particle, or rather, they are they own anti-particles. lets assume that such symmetry is only approximate and these ...
9
votes
5answers
7k views

What experimental proof has been found of Einstein's theory?

As a casual science reader, I've always found the implications of relativity (inconsistent clocks after near-light-speed travel and various space-time paradoxes) to be confusing and magical-sounding. ...
8
votes
1answer
388 views

What properties of Germanium make it suitable for Dark Matter detectors?

What properties of Germanium make it suitable for Dark Matter detectors? I tried googling but there was too many results describing the use of Germanium Chrystals at low tempretures for Dark Matter ...
12
votes
7answers
13k views

Explanation of “thermite vs ice” explosion

There are several videos of the reaction, where some amount of burning thermite explodes on a contact with ice. An "original" video: http://www.youtube.com/watch?v=IuPjlYxUWc8 A Mythbusters ...
4
votes
1answer
939 views

Measuring the vacuum permittivity

So I was reading the EF experiment that's used at the MIT to measure the vacuum permittivity and I was thinking about trying it just to see how it works: http://ocw.mit.edu/courses/physics/8-02x-...
6
votes
4answers
1k views

Atomic mass of Copper-63?

This URL lists the mass of Copper-63 as 62.9295975(6) and this other URL lists the mass as 62.939598. These values differ by almost exactly 0.01 which seems hard to explain by experimental error. ...
2
votes
2answers
221 views

Question about gravity probe B

I have a question about the gravity probe B experiment. According to this site: http://science.nasa.gov/science-news/science-at-nasa/2011/04may_epic/ The measurements they made confirm Einsteins ...
14
votes
2answers
988 views

Is there a good chance that gravitational waves will be detected in the next years?

Is there a good chance that gravitational waves will be detected in the next years? Theoretical estimates on the size of the effect and the sensitivity of the newest detectors should permit a ...