Fermilab’s DZero weighs in on an unexpected CDF result
June 10, 2011 | 9:38 am
This story first appeared in Fermilab Today on June 10, 2011.
Two months ago, CDF scientists reported an unexpected excess of proton-antiproton collisions that produce a W boson accompanied by two jets of particles. One possible explanation for the excess could be the existence of a new, unanticipated particle. Now the DZero collaboration has finished an independent analysis that tests the CDF result. Following the analysis procedure employed by CDF as closely as possible, DZero scientists did not find the same excess in the data. The collaboration will report their result and the details of their analysis at 4 p.m. today at a seminar at Fermilab.
The DZero collaboration found its data for the production of a W boson and two jets to be in agreement with the predictions by the Standard Model. The red peak below 100 GeV/c2 is a well-known Standard Model feature of the decays of W and Z bosons. If the CDF excess is interpreted as a new particle, the dotted line shows what such a particle would look like in the DZero detector. The DZero data shows no excess around 145 GeV/c2.
“Our data for collisions that produce a W boson plus two jets are in agreement with the predictions from the Standard Model,” says DZero co-spokesperson Dmitri Denisov. “We have looked among two hundred trillion particle collisions, and we don’t see the excess reported by CDF.”
Over the last 10 years, CDF and DZero have published more than 500 measurements of particle physics processes using two different particle detectors and independent analysis tools. The results agree more than 99 percent of the time, but there are rare occasions that the findings differ.
“This is exactly how science works,” says DZero co-spokesperson Stefan Soldner-Rembold. “Independent verification of any new observation is the key principle of scientific research. At the Tevatron, we have two experiments that, by design, can check each other.”
Now that the independent analyses have been completed, the difference between the two experiments’ results must be understood and resolved. Fermilab Director Pier Oddone and the CDF and DZero collaborations have agreed to create a task force that will coordinate a study of the two experiments’ analyses. The task force will consist of members from both experiments and Fermilab theorists Estia Eichten and Keith Ellis.
Today’s seminar will take place at 4 p.m. in the auditorium and will also be webcast.
The DZero paper has been submitted to Physical Review Letters, and a copy is available at the collaboration’s website. The CDF paper is available at their website.
– Kurt Riesselmann and Katie Yurkewicz
Kurt Riesselmann
Posted in energy frontier, Uncategorized |
4 Comments »
June 10th, 2011 at 11:18 am
It seems to me that the D0 analysis from 4.3 fb-1 data uses a dotted line CDF reference from their 7.3 fb-1 data set (expecting 100 events at the peak around 150 GeV). Shouldn’t that expectation be scaled to ~46 events consistent with the original CDF data set of 4.3 fb-1? In my blog post http://theoryofeverything.org/wordpress/?p=357, the overlay of the 4.3 fb-1 charts shows more consistency than reported.
June 11th, 2011 at 4:22 am
Sure, Higgs boson never explained the whole. But attempted to explain the oldest concepts of modern physics in quantum framework, which was given a raw demonstration by Galileo in 1589 by dropping objects from the Leaning Tower of Pisa. We start learning Physics with his laws of force and friction but never learn more than that ever during our whole tenure as students. A quantum explanation of mass and gravity thus will give a body to the 100 year old painting of quantum mechanics.
However, it’s not Higgs boson, but unnamed particles of two origins, which create gravity between ‘masses’. The discovery already took place in 2010 and has now been reported as a USPTO application which will be officially published by the US Patent Office. Some general landmarks are on my site http://www.anadish.com/. I have refrained from giving details, as the details are already under publication.
July 22nd, 2011 at 8:44 am
I think that if the detectors are working correctly, they should be able to repeat that energy range with CDF. If the same thing happens, they’ve either got a new particle that D0 can’t detect as efficiently, or CDF’s data analysis needs questioning.
July 22nd, 2011 at 9:37 am
One reason why the result of this may be interesting, is the fact that my father’s theory predicts there to be a particle at about this energy. For me to say what type of particle it is predicted to be however, might be considered spoiling the suspense. Either way, the result of the analysis shall indeed be very interesting.