Lifetime Definition and 131 Threads

Homework Statement Integrate field equations for a universe filled with radiation and with k = +1, λ = 0. Find ρ(a) ρ(t) and a(t). Find lifetime of the universe. Homework Equations Use first Friedmann equation which reduces to a'2/a2 + a-2 = kρ where k = 8∏/3 The Attempt at...

Homework Statement The total amount of oil in a well is 24000 barrels. The present rate of consumption is 100 barrels per year. How long will the gas supply last if the present yearly rate of consumption increases by 1% per year? Homework Equations We can use the approximation (1+x)^i =...

Homework Statement In special conditions, it is possible to measure the energy of a gamma ray photon to 1 part in 10^15. For a photon energy of 50 keV, estimate the maximum lifetime that could be determined be a direct measurement of the spread of photon energy. Homework Equations...

What are the accepted numbers for the decay rate and lifetime of Z-> mu+mu- and Z-> e+e- decays? also what is the unit for the decay rate? thank you!

For watches produced by a certain manufacturer, lifetimes follow a single-parameter Pareto distribution with alpha > 1 and theta = 4. The expected lifetime of a watch is 8 years. a) Calculate the probability that the lifetime of a watch is at least 6 years. b) For the same distribution as...

protons and neutrons interact with each other with the strong force, which is very strong however, there are many unstable nucleus which have a lifetime in the order of millions of years this is quite strange the time scale of strong interaction is many many orders smaller than that of...

Homework Statement If the exponent, α, in the mass-luminosity relationship is 3.0, estimate the lifetime of the above star. (You can assume that the Sun’s lifetime is 1 x 10^10 years). Homework Equations L*/Lsun = (M*/Msun)^α lifetime ∝ M/L ∝ M^-2 The Attempt at a Solution...

Homework Statement The proper mean lifetime of a \pi^{+} mesons is 26ns. (a) (i) What is the mean lifetime of \pi^{+} mesons traveling with \beta=\frac{v}{c}=0.73? (ii) What distance is traveled at this velocity during one mean lifetime? (iii) What distance would be traveled in the...

1. Homework Statement A pi meson (pion) and a proton can briefly join together to form a Δ particle. A measurement of the energy of the ∏p system shows a peak at 1236 MeV, corresponding to the rest energy of the Δ particle, with an experimental spread of 120 MeV. What is the lifetime of the...

The lifetime of a deuteron in the ground state of HD molecule has been calculated as 10^47 years. Obviously, at zero pressure and temperature it is slightly shorter, because hydrogen is solid at these conditions - but not much shorter, because in solid hydrogen at zero pressure the other...

Hi! In my calculation of photon lifetime, results are coming as complex number. So being a new one in this field I am just confused whether a photon lifetime ca be complex or somewhere I am making some mistake.

Experiments show that cosmic ray muons reach Earth surface in greater numbers than they should, unless relativistic time dilation is taken into consideration. It also seems to confirm the SR formula mathematically. However, looking at a lot of different experiment records, I have some doubts...

Maybe not on the macroscopic level, but what about on the molecular level? Is his DNA gets mutated by radiation from computer monitors, does that mean he has "evolved"?

Homework Statement I have to calculate the lifetime of a star that is 300,000 times as luminous as the sun and 24 solar masses. Homework Equations lifetime = k * m/l The Attempt at a Solution lifetime = 10^10 * (24/300000) lifetime = 800000 years I feel as if this is...

Hi all, I'm trying to construct a histogram from my data to illustrate evidence of muon lifetime. Attached is a .txt file that contains counts from our detector that correspond to different bin sizes (lengths of time muons were counted in detector) from our experiment. The file is 1x500...

Homework Statement An atomic spectrum contains a line with a wavelength centered at 460 nm. Careful measurements show the line is really spread out between 459 and 461 nm. Estimate the lifetime of the excited state that produced this line. Homework Equations Change in Frequency =...

Homework Statement Estimate the lifetime of CO2 in the atmosphere of Mars. Homework Equations The Attempt at a Solution What is he asking? How long has the CO2 been in the atmosphere? It just seems rather vague.

Homework Statement A beam of unknown particles travels at a speed of 2.5 x 10^8 m/s. When the particles are moving at this speed, their average lifetime is found to be 7,3 x 10^-8 s. What is their average lifetime when at rest? Homework Equations Well, Lorentz transformation for time...

I am trying to figure out how fast the Higgs decays and how far it travels in a detector at the LHC. Figure 2.5 in http://www.hep.lu.se/atlas/thesis/egede/thesis-node14.html gives decay widths of the Higgs as a function of its mass. For a Higgs of 125 GeV, it is 0.002 GeV. Using the...

Is it possible to calculate the lifetime of a virtual particle? For example is an electron and a proton form a virtual neutron that is off shell by 0.8Mev how long will it last? Is this something we can calculate? At first I would think it would be short lived because of the 0.8MeV energy...

Hello, I was wondering if the particle lifetimes as measured by observers increases in gravitational heavier areas. Relativity seems to suggest this, and there seems to be little criticism of this concept but I couldn't find any experimental evidence supporting this. Has this ever been shown? Or...

Homework Statement Given the following data, calculate the main sequence lifetime of the Sun (in years), assuming that all the initial mass is hydrogen and all of it is converted into helium. Mass of the Sun = M = 2x1030kg Luminosity of the Sun = L = 4x1032W Energy released in the...

The main cause of decay of particle accelerator beams is the scattering due to residual gas particles in the vacuum rings. I read some research suggesting (in my understanding) that most of these free gas particles (CO2, CO etc) are the result of desorption from the surface of the vacuum tube...

I have a cordless electric lawnmower that runs on sealed lead acid batteries. It is on it's second battery, which has noticeable degraded performance and will need replacing soon. My question is why the original battery, which was rated at 17 Amp-hours, lasted twice as long as this second...

I'm trying to understand why the Bc meson (anti b and c) has a lifetime of 0.46 picoseconds whilst the Bs, B+ and B- have lifetimes of ~1.6 picoseconds. Is this a density of states thing? or to do with the CKM elements? Thanks for any help.

Half of all people will develop some form of cancer within their lifetime? I believe I read somewhere that roughly 1 in every 2 (half) of ALL people will develop some form of cancer within their lifetime. Those figures seem awfully high, can anyone with an advanced knowledge of medicine confirm...

What is the liftime of a solid planet compared to the life of its sun?

i saw in car batteries in electric vehicles one can get more cycles (discharging them and recharging them) if one does not discharge it all the way. ie, its better to charge often even when it does not need them. but i had heard that for my phone battery it was better leave it charge all the way...

Homework Statement According to the energy-time uncertainty principle, the lifetime t of a state is inversely proportional to the uncertainty in the energy E. We consider the line λ= 656nm resulting from a transition in a hydrogen atom, from an excited state of lifetime 10-8s. (a) What is...

Hello all, I have a question more or less for everyone's entertainment. Organic Light Emitting Diodes (OLEDs) can be used to make flexible screens or other devices of similar function. However, one of the major obstacles to having a practical OLED devices is the lifespan of the product. OLED...

If electron-positron annihilation creates a photon, with "mass-energy", how long will the photon live for? It will travel at the speed of light until when?

The question provides momentum that the muons move with (3094 MeV/c) and proper lifetime (2.198 micro seconds) and asks to find the dilated lifetime. 2. t= to/((1-u^2/c^2)^1/2) and p=(mv)/((1-v^2/c^2)^1/2) 3. I think that I am supposed to use the momentum given to back order...

In lab, my partner and I are determining muon lifetime with a scintillator. I understand that the scintillator will help us find the average lifetime by measuring the difference between the time that a particle enters the scintillator and when in decays, but I am not able to figure out why this...

how would we know that the muon is decay into electron antineutrino and muon neutrino to give the muon lifetime of about 2microsecond?

Homework Statement The Y Meson has a rest mass of 9.6 GeV/c2 and a measured width of (Delta)E= 51keV. What is its approximate lifetime (delta)t? Homework Equations E=MC2 And.. who knows? The Attempt at a Solution We came to the conclusion that 9.6 GeV/c2 was related to E=MC2.. and we...

Hello, I'm new on this forum and I hope I will blend in nicely. I happen to have a couple of questions on the Alpha Centauri star in the constellation of Centaurus. I know the distance between this star and our milk way is huge, but suppose one could travel at the speed of light X 25, would...

hello, does the mean lifetime of a decaying nucleus changes with temperature? I generally think that mean lifetime of a given nucleus doesn't change with temperature. thanks for your valuable input.

Vincent van Gogh comes to mind as someone who gained fame only after their death. What others can you think of?

Homework Statement A muon is traveling with a speed of v = 2.995x10^8 m/s. Calculate the value of the dilated lifetime for this muon. Assume that the speed of light is c = 3.000 x 108 m/s and that the proper lifetime of the muon is 1.500 x 10-6 s. [SIZE="1"]Note: Do your calculations...

Homework Statement Kelvin could only see the photosphere (the glowing outer surface) of the sun, so didn't know how the mass was distributed inside it. How would the potential energy of the sun change if it was a hollow shell? (No numbers needed; just indicate whether it would be more or...

Homework Statement In using the experiment where a scintillator is connected up to PMTs, and the data is then recorded on the computer... The muon has already lived outside the scintillator for a large amount of time before it decays in the scintillator, so how is it that the experiment...

Homework Statement I have to find the Fermi Coupling Constant using my measurement of the muon lifetime. My measurement is 2.1786x10^-6s Homework Equations G_F=\sqrt{\frac{192.pi^{3}}{\tau.m_{\mu}}} The Attempt at a Solution I tried plugging in the numbers that I have and I get...

Hi all Please take a look here (just read the first paragraph): http://hyperphysics.phy-astr.gsu.edu/Hbase/quantum/parlif.html I am a little uncertain of why it is that we equal the spread in time ∆t to the lifetime of the excited state (in the above link they denote the lifetime by Γ)...

Hello. The question states that We have a globular cluster with total mass 10^6 times sun's mass. Assume that the main sequence lifetime of a solar mass star is 10 giga year, and a main sequence lifetime scales with mass as M^-2. What is the mass of the most massive main sequence stars in...

For neutron we all know, it has the 15 minutes of fame before it decays, what is the theoretical bound on proton's lifetime outside the nucleus, and to what it should it be dacayed to? As far as I can tell electron is a point particle and cannot be dissolved into other parts, are there any...

Hi, I am trying to understand exactly how and why the lifetime, or decay rate, of an atomic level determines the spectral width of the transition to this level. Also I would like to understand why the natural lineshape is a Lorentzian. I am familiar with the vague explanations involving...

Homework Statement Three proton decays per cubic kilometer of water per year are detected by an array of photomultipliers immersed in the sea. Find the mean lifetime of the proton. Homework Equations t = 1 / lambda The Attempt at a Solution How is it possible to work this out...

I have been doing an experiment on muon lifetime, and am wondering if my count rate is correct. A little about the experiment: I have two scintillators (plastic) set up above a lead glass absorber, and a third scintillator(plastic), under the lead glass to veto muons that do not stop in the...

could someone help me get started on a problem solving the photon lifetime in a cavity? i have 4 optical paths

Homework Statement The muon is an unstable particle that spontaneously decays into an electron and two neutrinos. If the number of muons at t = 0 is N_{o}, the number at time t is given by N = N_{0}e^{-t/\tau}, where \tau is the mean lifetime, equal to 2.2 \mu s. Suppose the muons move at a...