LAGUNA: Large Apparatus studying Grand Unification and Neutrino Astrophysics

The principal goal of LAGUNA is to assess the feasibility of a new pan-European research infrastructure able to host the next generation, very large volume, deep underground neutrino observatory. A research infrastructure able to host new generation underground neutrino detectors with total volumes in the range of 100,000 to 1,000,000 m³ will provide new and unique scientific opportunities, and very likely lead to fundamental discoveries in the field of particle and atroparticle physics, attracting interest from scientists worldwide.

The FP7 Design Study LAGUNA is a collaborative project involving 21 European institutions. LAGUNA brings together on one hand the scientific community, and on the other hand the industrial and technical experts able to help assess the feasibility of this infrastructure.

New frontiers

• The observatory will look for the unification of all elementary forces by searching for an extremely rare process called proton decay. Large size detectors like those envisioned in LAGUNA are the only way to address this question.
• The large size of the LAGUNA observatory will, in addition, allow the detection of a sufficiently large number of neutrinos from very distant galactic supernovae to understand their explosion mechanism.
• The observatory will also perform precision study of terrestrial, solar and atmospheric neutrinos.
• Last but not least, the outstanding puzzle of the origin of the excess of matter over antimatter in the universe after the Big Bang, and the recent measurements of neutrino oscillations and masses, point forward to the need to couple the LAGUNA observatory to advanced neutrino beams from CERN to study matter-antimatter asymmetry in neutrino oscillations.

Enhancing the European Research Area

The impact of LAGUNA on the development of a pan-European common scientific framework is large. The continuous interaction between institutions from different European countries makes LAGUNA not only a very advanced and challenging scientific project, but acts as an instrument of integration, mobility and dissemination. It favours the consolidation of an integrated pan-European scientific community, and strengthening the scientific and technological bases of the industrial community.

The hope is to lead the project into its next phase as one of the research infrastructures identified by the European Strategy Forum on Research Infrastructure (ESFRI Roadmap). If realized in Europe, the project will greatly contribute to the enhancement of the European Research Area (ERA) by strongly supporting new ways of doing science in Europe.

LAGUNA

SuperKEKB

We are pleased to announce the Groundbreaking Ceremony for the SuperKEKB project on November 18th, 2011. The ceremony will take place at 15:00 at Kobayashi Hall in the Kenkyu-Honkan Bldg., KEK, Tsukuba, Japan, and will be followed by a toast and party at the Subaru-no-Ma in the OKURA Frontier Hotel Annex starting around 18:30.

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KEKB upgrade plan has been approved

June 23, 2010 High Energy Accelerator Research Organization (KEK)

The MEXT, the Japanese Ministry that supervises KEK, has announced that it will appropriate a budget of 100 oku-yen (approx $110M) over the next three years starting this Japanese fiscal year (JFY2010) for the high performance upgrade program of KEKB. This is part of the measures taken under the new "Very Advanced Research Support Program" of the Japanese government. "We are delighted to hear this news," says Masanori Yamauchi, former spokesperson for the Belle experiment and currently a deputy director of the Institute of Particle and Nuclear Studies of KEK. "This three- year upgrade plan allows the Belle experiment to study the physics from decays of heavy flavor particles with an unprecedented precision. It means that KEK in Japan is launching a renewed research program in search for new physics by using a technique which is complementary to what is employed at LHC at CERN." <><> <><> SuperKEKB making headway toward higher luminosity <><> <><> <><> The proposed SuperKEKB electron-positron collider underwent a major design change last March. A team of a hundred experts is moving forward to create the enabling technologies needed to realize the next generation electron-positron collider. <><> Schematic view of SuperKEKB upgrade. Last March, the team changed their approach to the higher luminosity from high current scheme to small beam size scheme. 'Luminosity' is one of the most important values talked of when particle physicists refer to how good a collider performs. One must be careful with this term though; luminosity in accelerator science is not luminosity in the stars. It does not tell you how luminous any matters are, but rather how luminous collision events are. Luminosity refers to the rate of particle collisions, and is a measure of how efficiently an accelerator produces these events. With higher luminosity, interactions produce more particles and particle physicists have more data to use in exploring new area of physics. (Read previous issue for what they are looking for.) Scientists working at the electron-positron collider known as KEKB at the High Energy Accelerator Research Organization (KEK) have been and are paving new ways forward at the luminosity frontier. Our team of 100 experts has held the world luminosity record since 2001, repeatedly breaking their own records. The current luminosity of 2.11 x 1034 cm-2 s-1 exceeds KEKB's original design luminosity by more than a factor of 2. Now the team is working hard on a major upgrade of their state-of-the-art accelerator. When the upgrade is finished, the new facility will be known as SuperKEKB. SuperKEKB at one time: The high current option When SuperKEKB was proposed in 2003, the target luminosity was set to 2 x 1035 cm-2 s-1, about 20 times higher than the KEKB's original design value. Engineering it to higher luminosity involves three things: increasing the beam current, focusing the beams at the interaction point, and/or making the electromagnetic beam-beam interactions small. These correspond to varying values of the beam current, beta-function, and beam-beam parameter, respectively. The team's original approach was two-fold: to increase the beam current and the beam-beam parameter. This approach had been known as the high current option, and proved to be very successful for the SuperKEKB's precursor, KEKB. In 2007, KEKB's scientists introduced two accelerator cavities called crab cavities, one for the electron ring and one for the positron ring at KEKB. Particles travel in bunches in an accelerator ring. At the interaction point, the beams of electron-bunches and positron-bunches cross at an angle of 1.3 degrees. The newly installed crab cavities kick the head and tail of each bunch of particles so that bunches would make effective head-on collisions at the interaction point. This process is called crab crossing. With these crab cavities installed in the KEKB rings, the team was able to achieve the recent luminosity jump by fifteen percent. With the success of the high current scheme, KEKB researchers initially thought that they could aim for still higher luminosity by increasing the current, using most of the present configurations of magnets. The target luminosity was then raised up to 8 x 1035 cm-2 s-1. When simulations suggested that they could use the crab crossing to increase the luminosity up to six times higher, the team thought the SuperKEKB's target luminosity was within their reach. Then, a difficulty arose. The crab crossing effect improved the luminosity, but not as much as the simulation had predicted. "We are running simulations to explore possible scenarios that might keep the value low," explains Dr. Yoshihiro Funakoshi at KEK, the leader of the KEKB commissioning group, "It most likely be because of machine errors that simulations could not take into account." Aside from this problem, the high current option suffers from other difficulties. They will need to figure out how to cope with phenomena called coherent synchrotron radiation as it will stretch bunches in positron ring. The team also found recently that the beam size at the interaction point in the horizontal direction would have to be much larger than the designed value because of the constraint due to the large magnet size at the interaction region. Both these will result in luminosity drop. While the team continues their effort to overcome these difficulties, the design underwent a major change. The nano beam design <><> <><> <><> <><> A KEKB leader and beam optics group leader Prof. Haruyo Koiso (center) and the commissioning group leader Dr. Yoshihiro Funakoshi (right) celebrating the new world luminosity record with KEKB scientists and Belle collaborators. In March 2009, the team changed the course of their SuperKEKB design. This change was based on ideas from the Super B Factory, a next-generation electron-positron collider at the National Institute of Nuclear Physics (INFN) in Italy, proposed by a collaboration of former PEP-II scientists at SLAC and Russian physicists. Its target luminosity is as high as 1036 cm-2 s-1, and their base design is called nano beam option. This design takes small beam-size and a large crossing angle at the interaction point, instead of a high current. In other words, they approach higher luminosity by squeezing beams to nanometer-scale, rather than by increasing the beam intensity and the beam-beam parameter. The brilliance of the nano beam scheme is that it brings out the best of the interaction mechanism. At the interaction point, bunches of particles in the beam can get squeezed to narrower bunches by stronger magnetic fields, but this process saturates at some point because of what is called the 'hourglass effect'. The vertical beam size of beam bunches increase outward from the most focused point so that only very small portion of beam bunch is in focus. This focusing effect will be diluted when beams collide head-on. Why don't we then intersect electron and positron bunches only at the highly focused region of each bunch rather than the entire bunches in order to gain higher luminosity? That led to the nano beam concept. Using the nano beam scheme in the SuperKEKB design brings a number of advantages. One of the most important advantages is that it is greener. The beam current for this design will be at 4 Ampere for the low energy ring (2.3A for high energy ring), instead of the 9.4 A (4.1A) of the high current scheme. It follows that this scheme will be more economical one, because devices like radiofrequency power sources to sustain high current do not require as extensive extensions as with the high current option. With this design, "we think we will be able to reach luminosity of 8 x 1035 cm-2 s-1," says Funakoshi. "This will be an entirely different approach for SuperKEKB, but seems very promising for the high luminosity we need." Our entire accelerator team is now working hard on the research and development of each component for the new SuperKEKB design. There are multiple major technological hardships to be overcome by this fall when the team will meet to determine the technological feasibility and reach the final design completion. The final design will change many aspects of the accelerator, and require major upgrades in some area. The challenges of higher beam current The first such issues to be resolved are the unfortunate side effects of high beam current. Even with the nano beam scheme, the beam current will increase to twice as much of the present value. Accelerator researchers have known for years that for a high-current electron-positron collider there will be issue of electron-cloud effect in positron ring as well as excessive heating in vacuum chamber due to the strong radiation. Electron clouds form when radiation from accelerating charged particles-called synchrotron radiation-hits the wall surface and kicks out electrons into the chamber. Secondary electrons come out when those electrons hit wall surfaces, contributing to the formation of electron clouds. These electrons disrupt positron beam when they come near the beam. Photon Factory, also at KEK, was the first to observe this effect that heaves up the train of positron bunches. KEKB also confirmed this effect later, and further found a more serious case of a single-bunch instability that vibrates each bunch at much higher frequency. Vacuum group member Dr. Yusuke Suetsugu working at the test vacuum chamber he and his group developed. This Saturn-shaped special chamber has an antechamber for vacuum pump and another antechamber for electron clouds. The former antechamber will eliminate pump ports near beams, and is effective for both electron and positron rings. To counteract such phenomena, the team developed a clever vacuum chamber with two small antechambers, one on the left and one of the right. One antechamber suppresses the formation of electron clouds and the other contains vacuum pumps. They also wrapped the chambers between magnets with solenoid coils to reduce the effect of secondary electrons. According to Dr. Yusuke Suetsugu, a vacuum group member, the research and development for such beam chambers is crucial for SuperKEKB although it became less demanding since the new design, as the beam current is less than a half that of original high current option. The team has already developed several test antechamber from the prototype produced in collaboration with a Russian team in the Budker Institute of Nuclear Physics, and installed them in sections of the KEKB ring. The electron cloud is one of the central difficulties faced by accelerator scientists in designing new colliders. Other new colliders, such as the currently proposed International Linear Collider (ILC), are faced with the same problem. The ILC teams at KEK, SLAC, and Cornell University collaborate on the research and development of various mitigation techniques. "The collaboration is now exploring a possibility to introduce new and more effective mitigation mechanism inside the bending magnets," says Suetsugu. "We are in good shape for the research and development for this year." Small, powerful magnets <><> <><> <><> <><> Superconducting magnet group leader Dr. Norihito Ohuchi and the test station he developed for SuperKEKB's original design. He and his group members are now working on more challenging magnets for new nano beam design. The magnets developed and tested for previous design will still be used for sextupole magnets near the interaction region. The next set of challenges involves the superconducting magnets in the interaction region. According to superconducting magnet group leader Dr. Norihito Ohuchi, the new design will need eight strong quadrupole magnets placed deeper in the interaction region to squeeze the beam to nanometer scale. The first hurdle for the group is the design and fabrication of some unusually small quadrupole superconducting magnets whose inner diameters are only 4-8 centimeters. This is one-sixth the diameter of the KEKB quadrupole magnets. Making the magnets this small requires consideration of points that did not matter before. For example, the new nano beam design requires finer magnet current controls to protect magnets from magnet quench due to an excessive heating. Since the current density in the superconductor go beyond 2000A/mm2, the temperature of the magnets will go over 1000 degrees in Kelvin within about 50 milliseconds. Additionally, the accelerator design demands much smaller fabrication errors to acquire a field quality of a few 10-4 with respect to the quadrupole field. "No one has yet made a superconducting magnet with this small size and the high current density for the interaction region," says Ohuchi. The group is going to construct an R&D magnet by the end of this year and test it in early 2010. The development of this magnet, which will be one of the world's finest superconducting magnets, will be the key to the success of the new design. Beam optics and short beam lifetime Another major field of active research is the beam optics. The goal of beam optics research is to find a total solution for creating a beam with ideal properties (shape, emittance and lifetime) for the new nano beam design. This is done by studying the arrangement of magnets along the rings and in the interaction region. The beam optics group uses variety of magnets for different purposes: dipole magnets for bending, quadrupole magnets for beam focusing, and sextupole magnets for correcting beam chromaticity-a parameter that indicates dependence of beam optics on energy deviation. Depending on the arrangement of these magnets they are able to produce a variety of beam parameters.  KEKB's simulation group leader Prof. Kazuhito Ohmi (left) and supercomputer group leader at Computing Research Center Dr. Hideo Matsufuru in front of the supercomputer Ohmi uses for his beam-beam collision and beam instability simulations. Ohmi's successful simulation revealed mechanism of electron-cloud induced head-tail instability. "There are many ways those magnets can be arranged in the rings and in the interaction region," says Prof. Haruyo Koiso, a KEKB team leader and the beam optics group leader. "We need much better optics. We are going to explore many more magnet arrangements in the interaction region in great detail." The most serious issue in the nano beam scheme is the short lifetime of beams. Containing particles inside beam bunch is not easy for variety of reasons. When a quadrupole magnet squeezes a beam, the degree to which the beam can be focused depends on the energy of each particle in the bunch. This causes particles to be dispersed in a beam due to the energy differences. Scientists place sextupole magnets to fix the chromaticity, but the magnetic field created by the sextupole magnets also limits the area inside the pipe that a beam can go through undisturbed. The particles outside of this region can no longer be contained in the beam bunch. Many other sources of nonlinear effects other than the magnetic field due to sextupole magnets can influence on this region, called dynamic aperture, Accelerator scientists analyze the dynamic aperture in three dimensions: horizontal, vertical, and energy dimension. When the dynamic aperture is small, outer particles keep getting lost and the beam's lifetime becomes short. The problems in dynamic aperture the KEKB researchers face are more acute in nano beam scheme than in high current one, because in nano beam scheme the beam size at the interaction region will be reduced by a factor of ten. The optics group is making its best effort to simulate various possible configurations to complete the conceptual design for the rings and to develop a detailed model for the near interaction point. Every group in SuperKEKB is now working hard to test and simulate parts of the new nano beam design, including the beam monitors, beam control, beam transport, linac, damping ring, radiofrequency system, and magnet system. Meanwhile the SuplerKEKB team awaits approval for the project from the Japanese government. The fact that the nano beam option is both greener and lower cost option will certainly help. http://www-conf.kek.jp/superkekb/

Las Partidas de Nacimiento de las Partículas Elementales

Symmetry, una revista impresa y electrónica, sobre la física de partículas y sus conexiones con otros aspectos de la vida y la ciencia, , ha tenido la iniciativa de recolectar los documentos o medios que comprueban la paternidad de algunos de los descubrimientos más importantes relacionados con las Partículas Elementales.

Su valor histórico es innegable, más aún por lo que traslucen. Cuando Pauly postuló la existencia de lo que después conoceríamos como neutrinos, recurrió inicialmente a un grupo de físicos experimentales:"Thus, dear radioactive ones, scrutinize and judge". La vieja pizarra, tiza blanca y borrador incluido, es un verdadero legado a la memoria de científicos y académicos de Wiegand, al igual que la libreta que utiliza Ikawa del Departamento de Física de la Universidad para el borrador de su artículo.

1930. Postulación del Neutrino. Wolfgang Pauli

Para preservar la Ley de la Conservación de la Energía, tuvo que postular la existencia de alguna partícula, neutra, de bajo peso, para explicar la desaparición de la energía en el choque de dos nucleos atómicos. En aquel momento, Pauli la llamó "neutrons". Cuando en 1932 JamesChadwick descubrió una partícula neutra, recibió ese mismo nombre. Sin embargo, debido a su peso, no podía ser la partícula predicha por Pauli. Cuando Enrico Fermi desarrolla  una teoría sobre la interaccion debil de partículas, ntroduce un nuevo nombre para la partícula de Pauli: "neutrino":“little neutral one"

La carta fue enviada el 4 de diciembre de 1930 a un grupo de físicos nucleares que se reunían en Tübingen, Alemania. El documento fue obtenido gracias  a Lise Meitner,un científico que asistió a la reunión. El documento fue publicado por Symmetry en la edición de marzo del 2007.

Copia del documento original

Copia del documento traducido al inglés

1934. Fuerza Nuclear. Postulación del Mesón. Hideki Yukawa

El 1 de noviembre de 1934, Hideki Yukawa, profesor asistente en la Universidad de Osaka, comenzó a escribir el primer borrador de un artículo que le ganó el 1949 Premio Nobel de Física, explicando la fuerza que mantiene unidos los protones y los neutrones, que forman los núcleos atómicos.  Utilizó la teoría del campo cuántico de los electrones y los fotones como punto de partida. Yukawa propuso la existencia de una nueva partíla subatómica con peso mayor al electrón pero menor al del protón, después conocida como mesón  (del griego "mesos", medio), que media la fuerza nuclear fuerte, dentro del núcleo, entre  protones y neutrones.

El artículo fue publicado finalmente en "Proceedings of Physico-Mathematical Society of Japan", prediciendo rayos cósmicos con suficiente energia para producir una nueva partícula fuera del núcleo. En 1947, Cecil Frank Powell y su grupo de la University of Bristol encuentra el "pi meson" o "pion", una particula 270 veces menos que el electrón. En 1949, se convierte en el primer japonés en recibir el Premio Nobel. En 1950 lo obtiene Powell.

1955. Descubrimiento del Anti-Protón. Lawrence Berkeley National Laboratory

En 1954, en el Lawrence Berkeley National Laboratory, fue encendido el Bevatron, un acelerador construido con el propósito de descubrir el Antiprotón. Dos equipos de investigadores se organizaron para, por experimentos diferentes, encontrar al antiprotón. Dirigidos por Emilio Segre, los investigadores Owen Chamberlain y Clyde Wiegand tratan de identificar los antiprotones mediante la determinación de las masas y cargas de las partículas producidas por golpear los protones en un blanco fijo. Un segundo grupo, dirigido por Gerson Goldhaber en Berkeley y Edoardo Amaldi en Italia, registraría las colisiones en las emulsiones fotográficas y buscaría las explosiones de energía en forma de estrella se espera de la aniquilación protón-antiprotón.

Wiegand, uno de los investigadores, colocó una pizarra, cerca de la entrada de Bevatron,´para mostrar el progreso de su grupo. A las 4.30 p.m., del 6 de octubre de 1955, el grupo había encontrado 38 partículas negativas con la misma masa que el protón. Habian revisado 2 millones de eventos de partículas. Wiegand, seguidor del beisbol, agregó el rsultado de la Serie Mundial de ese año: New York Yankees y  Brooklyn Dodgers (4-3)

1976. Descubrimiento del Bottom Quark. John Yoh

El 17 de noviembre de 1976,  John Yoh, un investigador del experimento E288 del Columbia-Fermilab-Stony Brook  (Fermilab experiment E288). propuso la eistencia de una nueva partícula de una  masa de  9.5 GeV.Unos meses antes, se había anunciado, en la  Physical Review Letter, la existencia del "Upsilon" (Υ), aun a manera de fluctuación estadística, de masa de 6 GeV, desvaneciendose con mayor cantidad de datos.

En 1977, el Upsilón 9.5 resultó real. Resultó que era el Bottom Quark

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Symmetry es  producto de la colaboración del Fermi National Accelerator Laboratory y el SLAC National Accelerator Laboratory, ambos laboratorios nacionales financiados por la Oficina de Ciencia del Departamento de Energía de Estados Unidos,

Neu...???

Measuring elusive neutrinos flowing through the Earth, physicists learn more about the sun

Using one of the most sensitive neutrino detectors on the planet, an international team including physicists Laura Cadonati and Andrea Pocar at the University of Massachusetts Amherst are now measuring the flow of solar neutrinos reaching earth more precisely than ever before. The detector probes matter at the most fundamental level and provides a powerful tool for directly observing the sun's composition.

Del neutrino y de cómo solo conocemos un 4%

Aunque solo pocos comprendieron sus consecuencias, por aquello que la mayoría difícilmente apenas nos sabemos newtonianos como para celebrar un traspié cuántico, ese día poco importó tanta laguna acumulada. La velocidad de la luz había sido vencida, en 60 nanosegundos, destacaron los titulares, por los “neutrinos” ¿Los quiénes?

Eso me llevó a recordar a uno de mis profesores en filosofía de la naturaleza que por entonces se quejaba de tantas nuevas partículas elementales, es decir, aquellas que no están constituidas por otras más pequeñas. “¡Vaya! ¿Esto nunca terminará?”, se preguntaba. Hoy, algunos reportan la existencia de 56 de ellas. Tres, son neutrinos. Tienen masa pero muy poquita. Casi no interactúan con otras partículas y, con record o sin él, viajan, siempre, muy próximas a la velocidad de la luz. ¿Pero entonces, que pasó con la materia producto de átomos integrados por protones, neutrones y electrones, las únicas partículas elementales que aprendí en la secundaria?

La historia inicia 25 siglos atrás, en la vieja Grecia, con Leucipo y Demócrito, los primeros atomistas, que postularon un modelo donde el átomo era el único constituyente, impenetrable e indivisible de la materia. Hasta inicios del siglo XIX ese fue un supuesto filosófico. Todo cambió en 1808 cuando, gracias a la química, se contrastó experimentalmente su existencia. De 1897 a 1931 se descubre el electrón y sus órbitas estables, alrededor de un núcleo integrado por protones y neutrones, acabando así con la impenetrabilidad e indivisibilidad del átomo.

Desde los años setenta del siglo XX se inicia una carrera frenética de científicos descubriendo partículas aún más elementales que las subatómicas, los neutrinos por ejemplo. No era gratuito el revuelo de mi profesor universitario, más aún porque si en el pasado era legítima la identidad entre materia, átomos y partículas subatómicas, aquello había dejado de ser posible porque no todas las partículas elementales se mezclaban unas con otras y porque no todas las que se mezclaban se transformaban en átomos. Como los neutrinos.

Sin embargo, al finalizar la primera década del siglo XX, el orden fue restablecido mediante el llamado “Modelo Estándar” que establece que en el nivel más elemental toda la materia que conocemos “consta de solo un puñado de partículas fundamentales y cuatro fuerzas actuando entre ellas”. De acuerdo al “Proyecto Beacons of Discovery” del “International Committee for Future Accelerators”, esa imagen es “sencilla y elegante”.

El puñado de partículas son doce, conocidas como “fermiones”, divididos en dos grupos: “quarks” y “leptones”. Existen 6 quarks y 6 leptones El átomo sigue ahí, tan campante como siempre, aunque ya no como el viejo soberano y muy disminuida la antigua realeza de su corte subatómica. En el modelo vigente, solo cuando se combinan dos “quarks de tipo abajo” y un “quark de tipo arriba” se conforma un neutrón. Cuando lo hacen dos “quark arriba” y un “quark abajo” se genera un protón. El electrón es un tipo específico de leptón. Cuando todo eso se une, ya lo sabemos, se produce un átomo. Eso es lo que se aprende hoy, supongo, en secundaria.

E igual que siempre, cuando un átomo se une con otros termina en la “materia”, tal cual la vivimos todos los días. El carro, la bicicleta, el escritorio, el cuerpo humano, las flores. Sin embargo, los científicos han empezado a utilizar el concepto de “materia ordinaria” para distinguirla del resto de partículas elementales que no conducen a ella, como los tres neutrinos. No es poca cosa la distinción.

La “materia ordinaria”, la integrada por átomos, representa solo el 4% de los constituyentes del universo, donde el 96% restante son energía (73%) y materia (23%) oscuras, de las que no sabemos casi nada.

Es bueno que el neutrino haya tenido su día de gloria. No tanto por su presunto record de velocidad que puede que no lo sea. Más bien por lo que aun tiene que decirnos, por ejemplo, con relación al origen del universo o con la aceleración de su expansión o con aquel 96% que existe pero que no es “materia ordinaria”. Total, como Einstein escribió: "knowledge is limited. Imagination encircles the world".