Wednesday, 11 July 2012

Understanding the nature of matter


Fifty years ago , particle physicists faced an unexpected challenge . their best mathematical model could account for some of the natural force s that and behavior of matter at fundamental level , such as electromagnetism and the weak nuclear force responsible for radioactive decay .cut the models worked only if the particles inside of atoms had no mass. how could huge conglomerations of such particle - proteins people, planet- behave as they do if their constituent parts weighed nothing at all ?
         Some physicists invented a clever workaround . they suggested that a type of particle exists that had never been detected. it was eventually named f the British physicist peter Higgs . for a half -century , physicists searched for the elusive "higg particles" now following research conducted at CERN , the sprawling particles - physics laboratory near Geneva, the hunt is over . at first blush , the idea behind the Higgs particles outlandish . Higgs and his colleagues suggested that every elementary particle really is massless , just as the mathematical models require , and hence all particles would ordinarily zip around at the speed of light . but suppose that every thing around us - every single particles in universe - is immerse in huge , unseen vat of higgs particles . whenever most kinds of particles move from point A to point B , they continually bump into higgs particles , slowing their motion. When we observe them they appear to lumber along like holiday shoppers in a crowed store. from their slow motion we infer that they have mass.

a representation of traces of a proton- proton collision measured in the search for the Higgs boson is depicted in this handout by CERN, Physicists have found a new sub- atomic particles in their search for the higg boson , the particle that is believed to explain the mystery of mass
   While a 50 years search for hypothetical particles reminiscent of the bizarre fairytale might seem  quixotic . the higgs particles stands at the center of the "stander-ed model" of particle physics . Every experimental test of the model so far has matched theoretical expectations . in some striking examples  , the agreement between prediction and measurement has stretched out to twelve decimal places , making the stander-ed model the most accurate scientific  theory in human history . the model successfully accounts for three of the four basic forces of nature only gravity remain beyond its purview.higgs particles might have played an even more substantial role at earlier moment is cosmic history . my own research , along with that of the physicists around the world, has focused on what effects higgs particles might have just fractions of second after the big bang -effects that could explain the shape and fate of the universe .
        And yet , for all that we still had no direct evidence that higgs particles even exist , according to the stander-ed model , higgs particles scatter off each other , so they too. should have mass . the latest research indicates that higgs particles (if they exist ) should be among the most massive critters of the subatomic realm, more than 120 times as massive as the familiar proton.
                  To produce such particles in the laboratory requires revving up protons nearly the speed of light and smashing them together which the large Hadron Collide r at CERN  accomplishes trillions of times per second . the energetic collision produce all manners of debris , which physicists carefully track with huge  detector s and sift with sophisticated computer algorithms. Physicists confront two major hurls in their hunt for the Higgs , first they must identify patterns in the debris that could have come from production and rapid decay of a higgs particles The sought after signal is well understood in principle, given what we know about the stander ed model . so is the background noise from all of the other junk that comes flying out when two protons collide colossal energy . physicists searching for  a new  Higgs like needles in a mind - bogglingly large haystack must comb their data for anomalies in the debris that cannot be accounted for by known processes.
           the second difficulty concerns statistics . the rules of quantum theory , on which the slandered model is built , are at root probabilistic. there will always be statistical flukes  in the data , just as any series n produce an unexpected strings of seven heads in row .
                to know with confidence that the coin is ordinary , with no hidden features , one must log a sufficiently large number of coin flips and check whether the data include equal numbers of heads and tails over the long run . if the data still show a bias towards heads , on e may be justified in thinking that coin have some unusual properties .
              the same holds true for all of the chaff from the protons collision . before physicist can claim that their anomalies really come from higgs particles. they must gather enough data to rule out flukes .A CERN two independent team of physicists announced this month that their data were consistent with detection of higgs particle, bringing the 50 years hunt for one of the most fundamental bits of matter to successful conclusion.
            

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