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

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2
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1answer
389 views

How does physics scattering experiments relate to real life? And what does the scientist gain from such experiments?

How does physics scattering experiments relate to real life? And what does the scientist gain from such experiments? I am having a hard time figuring the answer out. Please help.
1
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2answers
259 views

Where to find cross section data for e- + p -> p + e-?

Where to find cross section data for e- + p -> p + e-? PDG's cross section data listing does not include it.
1
vote
0answers
139 views

What narrow-linewidth laser system runs at 2100nm with 1W of power?

For an experiment at our university we need a laser that runs at about 2.1 μm (about 20nm higher or lower would be fine too. We have found a multitude of lasers that achieve this (typically Thulium- ...
4
votes
1answer
765 views
8
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2answers
7k views

What is p_T? (transverse momentum?)

I've been looking at a few papers in experimental physics (from the ATLAS collaboration, for example) and I've often run across phrases such as "high-p_T electron." What exactly is p_T? Is it simply ...
4
votes
2answers
436 views

Have experiments ever suggested two different values to the same divergent series?

I believe to have understood that some physical experiments suggest finite values to divergent series (please correct me if I'm wrong, my understanding of these matters is limited). I heard, for ...
5
votes
4answers
3k views

Why can't echoes be heard inside a room?

If I go camping and shout anywhere, in the forest or on a cliff, I usually hear the echo of my voice. Why when I shout in my room I do not hear any echoes?
5
votes
1answer
1k views

What are the advantages of the ILC over the LHC?

USA Today has an article on Japan's interest as the site for the $10 billion future International Linear Collider. This accelerator will utilize electron/positron collisions (like CERN's former LEP ...
0
votes
2answers
727 views

Effect of coarse vacuum on consumer electronics?

What is the long-term effects of storing materials in consumer electronics in a vacuum? Ie, plastics, electronic circuits and optical glasses?
6
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0answers
187 views

Is there precision experimental evidence for Furry's theorem — that only even degree VEVs are non-zero?

Is there precision experimental evidence for or contradicting Furry's theorem -- that only even degree VEVs are non-zero, specifically for the EM field?
2
votes
1answer
98 views

Gravity waves detectors; are they all similar?

Are the gravity waves detectors all working on the same principle/effect ?
3
votes
2answers
775 views

Why is the observed signal the convolution of the true signal with the instrumental function?

Imagine we are observing a star. The light coming from a star enters an optical instrument that will give us some observed data, such as the spectrum of light say. What we observe is not the true ...
1
vote
1answer
189 views

Light filter for an experiment

I'm looking for a filter that lets through as many wavelengths as possible (from 200 to 5000 nm). Is that even possible?
2
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2answers
439 views

Gravitational waves detection, any news? [duplicate]

Is the detection of gravitational waves a reality with nowadays technology? Are there recent news?
21
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1answer
3k views

How did Rømer measure the speed of light by observing Jupiter's moons, centuries ago?

I am interested in the practical method and I like to discover if it is cheap enough to be done as an experiment in a high school.
4
votes
2answers
902 views

What do “local” and “global” mean when talking about standard deviations in experimental particle physics?

I found the following sentence: The excess is most compatible with a SM Higgs hypothesis in the vicinity of 124 GeV and below, but the statistical significance (2.6σ local and 1.9σ global after ...
1
vote
1answer
217 views

Light vs neutrino speed comparison in a real tunnel

Given current accuracy of the techniques, is it possible to identify a real, existing tunnel (stright I think) to make the direct comparison of the speed of light and of neutrinos? The hypotetical ...
6
votes
2answers
179 views

How should one combine the uncertainties from the ATLAS and CMS measurements?

First off, a naive theorist question - How are measurements divided between the different detectors at the LHC? I would imagine that for a short run time, say, the CMS detector is active and all the ...
5
votes
1answer
1k views

What's the Standard Model width of a 125 GeV Higgs?

There's a fairly broad mass spread in the new results out of Atlas and CMS. I'm curious how this fits with the expected SM width.
2
votes
0answers
346 views

Levitation rotation speed involving laser acceleration, pyrolytic graphite and a vacuum

The experment would involve a small NIB magnet levitating between or on the diamagnetic material pyrolytic graphite, unlike other forms of levitation this doesn't require power to run such as ...
4
votes
2answers
6k views

Testing the temperature of an open flame

How, and what device do you need, to obtain the exact temperature of an open flame? For the purpose of this question, you wanted to maintain 375 degrees. You can control the flame, but have no idea ...
8
votes
2answers
727 views

Quantum Computing, Qubit Creation/Entanglement

I am currently a high school student researching quantum computing. I was referred to this site by Google and a friend. Currently I am researching the qubit part of quantum computing. My question is ...
5
votes
1answer
360 views

What is the smallest distance between a decaying vertex and an interaction point a detector can measure?

A short lived particle is created at the interaction point and then decaying a distance $d$ away, in some detector. My question is what is the smallest distance $d$ that can be measured ...
1
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0answers
179 views

What are the most seminal Soviet papers in experimental physics? [closed]

Soviet physicists have made well-known contributions to many areas of theoretical physics, but I've heard much less about their experimental work. What are the most seminal experimental papers that ...
1
vote
1answer
170 views

Spin Echo Experiment [closed]

I'm doing an spin echo experiment for different dilutions of Glycerol as an undergraduate physics lab experiment. At the end of my experiment I will need to extend it and do some initiatives! I have a ...
3
votes
1answer
2k views

Escape velocity of a rocket standing on Ganymede (Moon of Jupiter)

I want to calculate the escape velocity of a rocket, standing on the surface of Ganymede (moon of Jupiter) and trying to leave Ganymede. My thinking was, the kinetic energy $E_{\text{KIN}}$ must be ...
-1
votes
1answer
618 views

Where to find experimental/theoretical value of (charge) radius of particles?

Where to find experimental/theoretical value of (charge) radius of particles like proton, neutron, $pi^+$, etc. ?
1
vote
0answers
85 views

How to set the electric potential on a certain boundary to a certain value experimentally?

In electrostatic boundary value problems, usually the potential is set to some function or a constant on a certain boundary. It is never taught or told in textbooks how such assignment might be ...
3
votes
5answers
2k views

About the Ether Theory acceptance

Why was the Ether Theory refused by Modern Physics? If you please explain me, I just wanted to understand it more.
1
vote
1answer
246 views

Depalma Free Energy fields

Few years ago I read some papers about Free Energy, written by Bruce de Palma, a physicist who is said to be the inventor of the N-Machine, which is an device that works with free energy latent in the ...
7
votes
2answers
195 views

How do the LASERs in LIGO realize that space has expanded as a gravitational wave passes by?

I read an article on LIGO, and I heard it mentioned that it is a nontrivial argument to say that the effect can be measured by interferometry. What happens to space as the wave passes? Does the light ...
4
votes
1answer
370 views

Photoelectric effect: Experimental Physics

Suppose you are doing an experiment to determine the work function of a metal.  You get $KE_1$, $\nu_1$ and $KE_2$, $\nu_2$.   We know that $KE = h\nu - W$ but when you solve the simultaneous ...
27
votes
2answers
332 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
5k 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
315 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 ...
11
votes
5answers
11k 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
102 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
403 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
141 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 ...
1
vote
0answers
65 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
268 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 ...
12
votes
2answers
414 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
767 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 ...
9
votes
1answer
292 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
18k 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
512 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
2k 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?