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Large Hadron Collider and Left-Right Symmetry in Nature

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Large Hadron Collider and Left-Right Symmetry in Nature Large Hadron Collider and Left-Right Symmetry in Nature Goran Senjanović ICTP, Trieste prepared for Univ. of Nova Gorica Friday, March 11, 2011 Symmetries and Particles Standard Model of all interactions (but gravity*) based on symmetries: local gauge * gravity negligible: 38 orders of magnitude weaker than em ⊙ sun - 1050 particles zero charge Friday, March 11, 2011 Theme 1 Parity : left - right symmetry images in the mirror P: all interactions? Fall and Rise(?) of Parity LHC - timely Friday, March 11, 2011 elementary particles - mass, charge, .. spin angular momentum at rest Quantum Mechanics: s=n/2 particles keep spinning Friday, March 11, 2011 electron (e), proton (p), neutron (n) neutrino (ν ) matter s = 1/2 (fermions) 24 m m 1GeV 10− gr p n 3 m 10− m e p neutrino mass ? Friday, March 11, 2011 “messengers” of forces: s=1 Friday, March 11, 2011 proton and neutron: quarks Gell-Mann ’64 proton neutron spin s=1/2 electron, neutrino relativistic equation for s=1/2 Dirac ’28 Friday, March 11, 2011 proton and neutron: quarks Gell-Mann ’64 proton neutron spin s=1/2 electron, neutrino relativistic equation for s=1/2 Dirac ’28 Friday, March 11, 2011 bombshell: anti-particles Dirac ’31 Skobeltsyn ’23 Chao ’29 Joliot-Curie ? e¯ positron = anti electron Anderson ’32 p¯ anti proton Segre’, Chamberlain ’55 `theorem’: anti-particle for every fermion (s=1/2) Friday, March 11, 2011 `theorem’: massive charged fermions Dirac ’28 Left and Right not neutrino ? Majorana ’37 Friday, March 11, 2011 Teoria simmetrica dell’elettrone e del positrone Il Nuovo Cimento Vol. 14 (1937) p. 171 Ettore Majorana only 32 Friday, March 11, 2011 Teoria simmetrica dell’elettrone e del positrone Il Nuovo Cimento Vol. 14 (1937) p. 171 Ettore Majorana last paper before his disappearance only 32 Friday, March 11, 2011 Teoria simmetrica dell’elettrone e del positrone Il Nuovo Cimento Vol. 14 (1937) p. 171 Ettore Majorana last paper before his disappearance only 32 Friday, March 11, 2011 Fermi: there are various types of scientists . Second, third rank - do their best, but do not go far. First rank, make great discoveries, fundamental for the development of science. And then, there are geniuses, like Galileo and Newton. Ettore Majorana was one of them; unfortunately he lacked common sense. Friday, March 11, 2011 Theme 2 Neutrinos `real’ particles? The creation of electrons out of “nothing” Neutrino-less double beta decay Racah ‘37 LHC - pp collisions can create electrons Keung, Gs ’83 Friday, March 11, 2011 Why are neutrinos so special? The most aloof particles A probe of new physics Friday, March 11, 2011 Nuclear and High Energy Physics Laboratory - Univ. Zaragoza 2/16/11 9:45 AM Research activities Main research lines Neutrino properties: double beta decay Direct nonbaryonic dark matter search Complementary research lines EU Network on cryogenic detectors Discovering neutrinos Canfranc underground laboratory produced in beta decay n p + e +¯ν → Continuous electron spectrum instead of a mono-energetic electron Neutrino properties: double beta decayexpected: E = Q One of our main activities is the research of the neutino properties through the nuclear double beta decay. The aim 1ν 0 ν of these experiments is the detection of the neutrinoless Chadwik ‘14 double beta decay or, in its absence, to get a bound on the effective neutrino mass. Its observation would be an confusion and evidence of physics beyond the Standard Model. confirmation in the late 20’s The two-neutrino decay mode is a conventional, although rare, second order weak process allowed within the Standard Model that has been experimentally observed inFriday, several March 11, 2011 isotopes (48Ca, 76Ge, 82Se, 96Zr, 100Mo, 116Cd, 150Nd...); it offers information about nuclear matrix elements involved in the process. Our experiments concentrate on the unobserved neutrinoless decay mode; it is a non-standard process, which observation would imply that neutrinos are massive Majorana particles and would even imply the existence of a right-handed weak coupling. Our group is and has been involved in experiments searching for the neutrinoless double beta decay of several isotopes: 76Ge, with natural (Coinc bb/g) and enriched Ge (IGEX) semiconductors and 78Kr with a kripton enriched ionization chamber (Kripton). Direct nonbaryonic dark matter search text The other fundamental research line of our group is the http://www.unizar.es/lfnae/ipaginas/ip0300.html Page 1 of 3 Nuclear and High Energy Physics Laboratory - Univ. Zaragoza 2/16/11 9:45 AM Research activities Main research lines Neutrino properties: double beta decay Direct nonbaryonic dark matter search Complementary research lines EU Network on cryogenic detectors Discovering neutrinos Canfranc underground laboratory produced in beta decay n p + e +¯ν → Continuous electron spectrum instead of a mono-energetic electron Neutrino properties: double beta decayexpected: E = Q One of our main activities is the research of the neutino properties through the nuclear double beta decay. The aim 1ν 0 ν of these experiments is the detection of the neutrinoless Chadwik ‘14 double beta decay or, in its absence, to get a bound on the effective neutrino mass. Its observation would be an confusion and evidence of physics beyond the Standard Model. confirmation in the late 20’s The two-neutrino decay mode is a conventional, although rare, second order weak process allowed within the Standard Model that has been experimentally observed inFriday, several March 11, 2011 isotopes (48Ca, 76Ge, 82Se, 96Zr, 100Mo, 116Cd, 150Nd...); it offers information about nuclear matrix elements involved in the process. Our experiments concentrate on the unobserved neutrinoless decay mode; it is a non-standard process, which observation would imply that neutrinos are massive Majorana particles and would even imply the existence of a right-handed weak coupling. Our group is and has been involved in experiments searching for the neutrinoless double beta decay of several isotopes: 76Ge, with natural (Coinc bb/g) and enriched Ge (IGEX) semiconductors and 78Kr with a kripton enriched ionization chamber (Kripton). Direct nonbaryonic dark matter search text The other fundamental research line of our group is the http://www.unizar.es/lfnae/ipaginas/ip0300.html Page 1 of 3 conservation of energy Pauli ‘30 a new neutral particle Chadwick ’32 neutron `brother’ of electron neutrino (small neutron) leptons Fermi (Amaldi) (light) Friday, March 11, 2011 how to see it? p +¯ν n +¯e → 44 2 cross section tiny: 10− cm 22 2 compare with electron: σ 10− cm 1020cm mean free path 70 million times distance earth-sun helps understand John Updike Friday, March 11, 2011 NEUTRINOS, they are very small. They have no charge and have no mass Cosmic Gall And do not interact at all. The earth is just a silly ball by John Updike To them, through which they simply pass, Like dustmaids down a drafty hall Or photons through a sheet of glass. They snub the most exquisite gas, Ignore the most substantial wall, Cold shoulder steel and sounding brass, Insult the stallion in his stall, And scorning barriers of class, Infiltrate you and me! Like tall and painless guillotines, they fall Down through our heads into the grass. At night, they enter at Nepal and pierce the lover and his lass From underneath the bed-you call It wonderful; I call it crass. Friday, March 11, 2011 NEUTRINOS, they are very small. They have no charge and have no mass Cosmic Gall And do not interact at all. The earth is just a silly ball by John Updike To them, through which they simply pass, Like dustmaids down a drafty hall wrong Or photons through a sheet of glass. They snub the most exquisite gas, Ignore the most substantial wall, Cold shoulder steel and sounding brass, Insult the stallion in his stall, And scorning barriers of class, Infiltrate you and me! Like tall and painless guillotines, they fall Down through our heads into the grass. At night, they enter at Nepal and pierce the lover and his lass From underneath the bed-you call It wonderful; I call it crass. Friday, March 11, 2011 great pessimism Pauli regrets inventing a particle that “will never be seen’’ Cowan and Reines ‘56 large flux of neutrinos Savannah River reactor 13 2 1 Φ= 10 cm− s− #events=ΦσnV V = 105 cm3 about 10 per hour :) Friday, March 11, 2011 The Reines-Cowan Experiments The Reines-Cowan Experiments lectron, namely, 0.51 million electron was about 28 inches in diameter and keep the toluene scintillator warm; olt (MeV). The two gamma rays 30 inches high (see photo on this otherwise, it would turn from transpar- would accelerate electrons through page), and 90 photomultiplier tubes ent to cloudy. Soon, they discovered The Whole-Body Counter Compton scattering and initiate a cas- penetrated its curved walls. that one of the brands of mineral oil ade of electrons that would eventually The phototubes were connected in carried by a local druggist, when In 1956, Ernest C. Anderson, Robert Schuch, James Perrings, and Wright ause the liquid to scintillate. The tiny two interleaved arrays, each of which mixed with suitable chemicals, could Langham developed the whole-body counter known as HUMCO I. Its flash of visible light, efficiently would produce an electrical pulse in serve as another liquid scintillator. design was a direct spinoff from the development of the first large liquid- onverted into an electronic pulse, response to a light signal in the detector. Having a hydrogen density different scintillation detector used in Reines and Cowan’s neutrino experiments at would be the signal of the positron. The two pulses would then be sent to a from that of toluene, the mineral oil Hanford. HUMCO I measured low levels of naturally occurring radioactivity The new idea was to detect not only prompt-coincidence circuit, which would yield a different measured rate in humans.
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