Hi All! Great news: the CMS Experiment, just a moment ago, announced that the LHC delivered 5fb-1 today!
Figure 1: Proof. It happened. (Image: Mine)
This is terrific news and if you happen to see a member of CERN’s accelerator division, be sure to congratulate her or him.
Figure 2: Total (integrated) luminosity delivered to (red) and recorded by (blue) the CMS detector. (Image: CMS)
To give a little context, 1 fb-1 (pronounced: one inverse femtobarn) worth of data is measure of the number proton collisions (scaled by a bunch of physics and efficiency parameters) and is the equivalent of 70 trillion proton-proton collisions. So 5 fb-1 is 350 trillion proton-proton collisions, which is 3.5 × 1014 = 350,000,000,000,000 proton-proton collisions. Before the start of collisions this year, the LHC had only delivered about 35 pb-1 (0.035 fb-1), which is only about 2.45 trillion = 2,450,000,000,000 proton-proton collisions. In other words, 99.3% of the data generated by the LHC came between this past March and Today. How can you not be impressed by that? 
Figure 3: Total (integrated) luminosity recorded by ATLAS (black/behind green), CMS (green), LHCb (blue), and ALICE (red). (Image: CERN)
Figure 4: Log of total (integrated) luminosity recorded by ATLAS (black/behind green), CMS (green), LHCb (blue), and ALICE (red). (Image: CERN)
Due to detector efficiencies and such, not all the data generated is recorded. The above plot, generated & continuously updated by CERN, shows that ATLAS and CMS have a small bit before reaching 5 fb-1. However, it is very reasonable to suggest that both experiments will have recorded 5 fb-1 before the end of the third week of November October. (Thanks to Achintya & Dave for catching this mistake. I have “week 43” in my notes for this post, so I have no idea how I ended up with the November date.)
As always, happy colliding.
- richard (@bravelittlemuon)
PS. I refer you to a previous post about what the experiments can do with 5 fb-1.
Congratulations. Keep the path.
hopefully ATLAS & CMS will record around 5fb-1 by the end of next week – which is the end of proton running for this year! (November is for heavy ions)
Thanks Dave for pointing this out!
Sorry, guys, but the Higgs is just a chimera because quarks are composite. You may say now ‘come on, we haven’t seen it’, and the truth is that we have seen several indications of it. The first one was found in 1956 by Hofstadter when he determined the charge distributions of both nucleons. (one can see them around p. 450 (depending on edition) of the Berkeley Physics Course, vol. 1 (Mechanics)). We clearly see that both nucleons have two layers of internal constituents. Unfortunately these results were put aside from 1964 on due to the success of the quark model and of QCD later on. From 1985 on we began to see more indications of compositeness, but we were so enthusiastic with the SM that we didn’t pay much attention to them. A partial list of them: 1) in 1983 the European Muon Collaboration (EMC) at CERN found that the quarks of nucleons are slower when the nucleons are inside nuclei; 2) in 1988 the SLAC E143 Collaboration and the Spin Muon Collaboration found that the three quarks of the proton account for only half of its total spin (other subsequent collaborations (EMC in 1989 and Hermes in 2007) have confirmed this result which is called the proton spin puzzle); 3) in 1995 CDF at Fermilab found hard collisions among quarks indicating that they have constituents (this was not published because CDF didn’t reach a final consensus); 4) Gerald Miller at Argonne (Phys. Rev. Lett. 99, 112001 (2007)) found that close to its center the neutron has a negative charge equal to -1/3e (inside the positive region with +1/2e); 5) new measurements of the EMC effect have been carried out by J. Arrington et al. at Jefferson Lab and they have shown that the effect is much stronger than was previously observed; etc. Please, take a close look at the papers Weak decays of hadrons reveal compositeness of quarks and The Ultimate Division of Matter. The former is a definitive proof of quark compositeness. The model completely agrees with the recent work of G. A. Miller (Phys. Rev. Lett. 99, 112001 (2007)) as to the charge distribution in the neutron. According to his findings the neutron has a negative charge very close to its center and this is in line with my proposal for the charge distribution in the neutron as you can see on page 9 of the paper Weak decays of hadrons reveal compositeness of quarks. According to the model there has to exist a negative charge very close to the center which is the result of the sum of the charges of primons (prequarks) and , and it is equal to -1/6+(-1/6)=-1/3. When this is summed up to the charge of p1 which is +5/6 we obtain that the total positive charge is (-1/3)+(+5/6)=+1/2 which agrees with the results of Hofstadter and Hermann. The outer negative charge is, of course, -1/2 . According to the model the proton has a similar inner structure and I hope that this will be experimentally found in the near future. Of course, the observed negative charge of -1/3 close to neutron’s center cannot be attributed to the d quarks because as the neutron is a udd system none of the three quarks should spend much time close to the neutron’s center. We can thus understand what is behind the Kobayashi-Maskawa matrix elements: the transitions with different Sigmas. And there is, of course, a new SU(2) vector current related to Sigma. As the paper shows, primons (preons or prequarks) have already been found a long time ago. The model solves the quark mass problem, the proton spin puzzle, the hierarchy problem and paves the way for the understanding of the Kobayashi-Maskawa matrix. And, moreover, shows that the weak decays of hadrons are directly related to selection rules dictated by a new quantum number (and a vectorial current in this case). The model leaves the leptons elementary and thus does not propose any change in the electroweak sector of the SM for leptons. The model is quite consistent with the absence of the Higgs boson as has been found out by the LHC so far, and hints that we have to probe further the low energy scale for finding out the inner structure for the proton, and then we will be able to establish a new direction for the origin of the quark masses. Of course, it is not a matter of chance that the weak decays of hadrons are governed by Sigma. That is why all newly found hadrons at the LHC obey selection rules dictated by Sigma. The explanation for the EMC effect is simple: The EMC effect is another proof of the compositeness of quarks and the effect has its origin in the interactions among the primons of the outer layers of neighboring nucleons. That is, the outer layers of primons allow the formation of bonds among nucleons and, of course, this slows down the motion of quarks. And that is how we can explain the large electric quadrupole of the deuteron. Please, find included a rough calculation of it based on primons (prequarks) which yields the right order of magnitude. As the deuteron is stable we expect the binding to happen by means of the interaction between the outer p1 of the proton and the outer p3 of the neutron. And that is why it does not decay even having 3 d quarks. We can also explain why the alpha particle has no electric quadrupole moment and why it has a hole in the middle. Another striking feature is the very high instability of Be8. As you know it lasts only 10^(-23)s and breaks up into two alpha particles. Within the framework of the model we clearly see that it is impossible to bind two alpha particles. The above mentioned papers can be directly accessed from the site http://www.scientiaplena.org.br and the paper Weak decays of hadrons reveal compositeness of quarks can also be accessed from the CERN Document Server at http://cdsweb.cern.ch/record/1136006/?ln=sv. Also both papers can be accessed directly from google. The papaer Weak decays of hadrons reveal compositeness of quarks is right at the top on Google in the subjects Weak decays of hadrons, decays of hadrons and weak decays.