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42 votes

What is the evidence for 'billions of neutrinos pass through your body every second'?

The existence of the neutrinos was established using energy and momentum conservation in neutron decays. There have been experiments with neutrino and antineutrino beams both at Cern and Brookhaven ...
anna v's user avatar
  • 234k
33 votes
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In particle colliders, according to QM, how are two particles able to "collide"?

The answer is basically the one you've suggested. When we collide particles in e.g. the LHC we are not colliding point particles. We are colliding two wavefunctions that look like semi-localised plane ...
John Rennie's user avatar
26 votes
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Why is Higgs particle detected much later than top quark when it's lighter?

With both particles you cannot detect them within their own lifetimes, only look at what they decay into. The top decays to a b jet and W (which can then become fermion anti-fermion or leptons) and is ...
Lio Elbammalf's user avatar
22 votes
Accepted

What is the evidence for 'billions of neutrinos pass through your body every second'?

As others have noted, the neutrinos come from the sun. Given that, there are two broad ways of estimating the flux of neutrinos: one is theoretical, and the other is experimental. The theoretical ...
Richter65's user avatar
  • 1,058
21 votes
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How can an electron fake a jet?

Hadronic jets deposit a significant fraction of their energy in the electromagnetic calorimeter, for example because they can contain neutral pions that decay as $\pi^0\to\gamma\gamma$, bottom/charm ...
atlas-insider's user avatar
21 votes
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How come I never see cosmic rays in steam like they appear in a cloud chamber?

Cloud chambers require a supersaturated environment such as one created by cooling a sealed chamber filled with alcohol vapor. The high velocity cosmic ray particles ionize the gas molecules they come ...
Stel's user avatar
  • 325
20 votes

How can an electron fake a jet?

Those of us who've worked at JLAB (and those who worked at SLAC) know that energetic electrons create a lot of hadronic junk when incident on significant amounts of matter. Think about Deep Inelastic ...
dmckee --- ex-moderator kitten's user avatar
14 votes
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Solid angle subtended by a circle

If you take an object and project it radially outward onto the surface of a sphere the area of that projection divided by the square of the sphere's radius is the solid angle. That's the general ...
Sean E. Lake's user avatar
  • 22.6k
13 votes

Is it possible to detect a particle, without energy transfer?

All detection requires a signal, which in turn requires energy. You can't detect without taking energy from the signal!
G.Bruce's user avatar
  • 352
13 votes
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What is the control group in neutrino detection?

Short answer - one can detect what direction neutrinos come from. Neutrino detectors don't just count neutrino collisions. Neutrinos either hit something in the detector or they themselves are ...
AXensen's user avatar
  • 7,425
12 votes
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What is the *DETECTOR* in the double slit experiment and how does it work?

I misunderstood your question at first. I thought you were asking about the detector downstream of the double slit, where the interference pattern is visible; every practical double-slit experiment ...
rob's user avatar
  • 91.1k
11 votes

What is the *DETECTOR* in the double slit experiment and how does it work?

I watched a couple of videos on the double slit experiment and I had exactly the same question as the original poster (Amr Berag) and stumbled upon this post and was just wondering how come everyone ...
Caezar 69's user avatar
  • 111
10 votes
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Is it possible to detect a particle, without energy transfer?

We can use a qubit as a particle detector that doesn't change the particle's energy. This can be implemented as follows. We start out with a qubit initialized in the state $\left|0\right>$ and we ...
Count Iblis's user avatar
  • 10.2k
9 votes

How can an electron fake a jet?

Edit: I am leaving this in because some effort has been made to present how decisions are made on complicated channels.The simple answer by @atlas-insider clarifies the general point that the OP is ...
anna v's user avatar
  • 234k
9 votes

In particle colliders, according to QM, how are two particles able to "collide"?

Besides what other people have said, it's worth looking at the numbers that enter the uncertainty relation $$ \Delta x\cdot\Delta p \gtrsim \hbar. $$ A quick web search tells me that the momentum in ...
tobi_s's user avatar
  • 1,321
9 votes
Accepted

Why are there fixed target experiments?

The target density is much greater, i.e you don't have a bullet trying to hit another bullet but rather a single bullet trying to hits lots of (more) densely packed targets. As a result, the ...
ZeroTheHero's user avatar
  • 45.8k
8 votes

How does one detect a single photon?

As strange as it may be to hear, the double-slit experiment conducted one photon at-a-time with "detectors at the slits" is nothing short of a myth. No such experiment has been reported in a peer-...
David Reishi's user avatar
8 votes

What is wrong with my setup of cloud chamber?

My personal experience is that the sponge (I used felt) needs to be thoroughly soaked in alcohol. Methanol (easier to obtain than pure ethanol) seems to give the best results. With that set up I ...
Gert's user avatar
  • 35.4k
7 votes
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Cloud chamber video showing large particles - What are they?

I tutor a cloud chamber workshop at CERN weekly, so I have some regular experience with recognising cloud chamber tracks. There are only four particles (plus their antiparticles) we can observe in a ...
freddieknets's user avatar
7 votes

What is wrong with my setup of cloud chamber?

You said, you attached your americium to the box. As far as i know, americium is an alpha emitter, so the alpha-particles should be blocked by the box. Try to put it inside the box. Maybe, this helps....
dudakl's user avatar
  • 206
7 votes

What causes the spirals to be inward in the bubble chamber images?

In a cloud chamber (or any other detector) the particles are moving through a material medium, so they steadily lose energy (that can also suddenly lose energy which results in a kink in the track). ...
dmckee --- ex-moderator kitten's user avatar
6 votes
Accepted

What is wrong with my setup of cloud chamber?

I tutor a cloud chamber workshop at CERN weekly, and during the development of this workshop several setups where tested until the (relatively) easiest way to build one was found. Based on the video ...
freddieknets's user avatar
6 votes

Why is it not possible to measure the individual neutrino mass from $\beta-$decay?

There cannot be enough accuracy in the momentum and energy measurements of the end products of beta decay, only limits can be determined because of measurement errors. See this link for a recent ...
anna v's user avatar
  • 234k
6 votes

What are some household sources of radiation detectable with a geiger counter?

Frankly (and luckily...) I doubt that something useful will be suggested beyond what you already list. But depending on where you live, you could try to measure a difference in the radioactivity in ...
rfl's user avatar
  • 6,475
6 votes

What are some household sources of radiation detectable with a geiger counter?

You can get thoriated tungsten electrodes from welding supply shops. Rock samples differ considerably in their radioactivity, so try different rocks. Here in northeast Massachusetts there's quite a ...
John Doty's user avatar
  • 21.5k
5 votes
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Radon or cosmic ray?

Unless your student is purposely placing a radioactive source into the chamber, or there are sources near the chamber, the more likely suspect is a cosmic ray if you are seeing condensation trails. ...
docscience's user avatar
  • 11.7k
5 votes
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Why are needed seperate detectors for muons?

Muons interact with the electromagnetic and weak interaction. They are ~200 times heavier than the electrons. In this link the behavior of charged particles with matter is discussed. Generally heavy ...
anna v's user avatar
  • 234k
5 votes

Is it possible to detect a particle, without energy transfer?

As a rule in order to detect a set of excited quantum states you have to input energy necessary to excite the harmonic oscillator modes of those states. If you want to detect the Higgs particle, which ...
Lawrence B. Crowell's user avatar

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