http://www.physics.umn.edu/rss/ en-us http://www.physics.umn.edu/images/BrokenbarIT3.jpg http://www.physics.umn.edu http://www.physics.umn.edu/about/news/4051/ <img src="http://www.physics.umn.edu/stateless/imagedb.html?type=thumbnail&id=5331" align="left" hspace=10 vspace=10 /><div class="wikitext"><p>Greg Pawloski is an expert on antimatter. As such he works on one of the great unsolved mysteries of physics: what is the cause of the great asymmetry in matter and antimatter? Physicists have long theorized that there are antiparticles for every particle in the Universe and that these annihilate one another in pairs. Yet, if there were an equal number of anti-matter particles, there would be no matter in the Universe.</p> </div><br/><br/><div class="wikitext"><p>Pawloski looks for muon anti-neutrinos going to electron anti-neutrinos on the MINOS neutrino experiment. Pawloski says this is a new channel for MINOS. In the past, MINOS looked at the matter neutrino transitions, but not for the appearance of anti-matter neutrinos.</p> <p>"A reason we are looking to see if matter and anti-matter behave differently," Pawloski says, "if they do behave differently than is predicted for this mode then that's totally unexpected and might indicate new physics." MINOS is winding down to make way for the new neutrino experiment NOvA, and will stop taking data in Spring, 2012. Pawloski expects his analysis will be completed within a year. <br /> Pawloski also works on NOvA, looking for disappearance of anti-muon neutrinos and muon neutrinos. “Again, we’re looking for a difference between matter and anti-matter; a possible new interaction between neutrinos and matter. Is there something out there that we’re not expecting that will lead us forward in knowledge? We live in a universe that’s dominated by matter. "In our theories you always get matter and anti-matter together, but where is all the anti-matter?” <br /> Pawloski’s job might sound a little like that of Mr. Scott the Engineer on Star Trek, but as a data analyst his work consists of computer software coding. Pawloski is running simulations of data they expect to see and then will use both the simulations and future data samples to develop new techniques for when he gets the real data from the detector that is being built at Ash River, MN. Pawloski says that most of this analysis will have to take place before NOvA begins taking real data with the detector at Ash River in 2013. "There’s work to be done before you actually look at the data and attach meaning to it."<br /> <br /> The way NOvA will work is similar to MINOS. A beam will be fired from Fermilab, through a near detector, 100 meters underground. Particles will then travel through the Earth to a Far Detector in Northern Minnesota. The main difference is that the NOvA Far Detector will be on the surface rather than in the Soudan Underground mine so that they can measure the neutrinos as they come in at a different angle. Pawloski says that the far detector needs to much bigger than the near detector because, like pellets from a shotgun, the particles spread out as they get further from the source.</p> </div><br/> http://www.physics.umn.edu/about/news/4051/ Thu, 05 Jan 2012 00:00:00 CST http://www.physics.umn.edu/about/news/3971/ <img src="http://www.physics.umn.edu/stateless/imagedb.html?type=thumbnail&id=5261" align="left" hspace=10 vspace=10 /><div class="wikitext"><p>Many a student has sat in freshman physics and asked, “when am I ever going to use this in real life?” Eric Thrane, a postdoctoral researcher in Professor Vuk Mandic’s LIGO group would answer that question by introducing you to Jeff Mondloch, an undergraduate working on a prototype pendulum for an interferometer designed to measure gravitational-waves–– minute ripples in the fabric of spacetime.</p> </div><br/><br/><div class="wikitext"><p>Using a basic pendulum equation that everyone learns in freshman physics, period is proportional to the square root of length, Mondloch and Thrane are attempting to create a pendulum with a period of fifty seconds. A conventional pendulum with a fifty second period would have to be taller than the Sears Tower, which is not practical for a physics experiment. Thrane and Mondloch are working to create a compact prototype, which is less than a meter long, but uses high-powered magnets to increase the pendulum period. The pendulum will be used to suspend mirrors in an interferometer––a device consisting of a series of mirrors, in which a split beam of light travels in L-shaped paths before being recombined. Physicists compare the light travel times for each path to determine if one path becomes longer than the other due to a passing gravitational wave. “If we just bolted mirrors down,” Thrane says, “they wouldn’t be able to move under the influence of a gravitational wave. By suspending the mirrors with wires, they behave as though they are freely falling, at least above the pendulum’s resonant frequency. To measure gravitational waves at lower frequencies, however, we must lower the pendulum’s resonant frequency. Previous LIGO experiments measured down to 40 Hertz, Advanced LIGO is designed to get down to 10 Hertz, but Jeff and I are shooting for 1 Hertz.”<br /> Jeff Mondloch is a junior double majoring in Physics and Philosophy. Eric Thrane’s primary role on LIGO is data analysis. Thrane says that his work goes beyond developing software tools: “Before we begin coding, we have to think about the astrophysics: what’s out there and how can we analyze the data to learn something about the universe. What physics can we do with LIGO to use it to its full capacity?”<br /> The University of Minnesota gravitational-wave group is a part of the LIGO Scientific Collaboration, which aims to detect gravitational waves with the new Advanced LIGO experiment. There is strong indirect evidence for gravitational waves, and they are predicted by Einstein’s theory of general relativity. Even for pessimistic models, Advanced LIGO expects to detect gravitational waves. “Advanced LIGO is as sure a bet as you can get in this business,” Thrane says, “and it is scheduled to begin taking data in 2014.”</p> </div><br/> http://www.physics.umn.edu/about/news/3971/ Mon, 14 Nov 2011 00:00:00 CST http://www.physics.umn.edu/about/news/3801/ <img src="http://www.physics.umn.edu/stateless/imagedb.html?type=thumbnail&id=4971" align="left" hspace=10 vspace=10 /><div class="wikitext"><p>Ask Brian Andersson, assistant education specialist, in charge of the School of Physics and Astronomy lecture demonstration area, what his favorite demo is and he’ll tell you: “anything that explodes.” Which could describe a significant number of the over 1,000 demonstrations that Andersson has in his repertoire.</p> </div><br/><br/><div class="wikitext"><p>There’s the vacuum bazooka that shoots a ping pong ball at the speed of sound, blasting clean through a set of aluminum cans. There’s the cast iron “bomb” which goes off inside of a plexiglass case. Not to mention the set of 100 mousetraps which goes off in a minute-long frenzy of snapping. Brian confides that the latter is one of the most difficult and nerve wracking to prepare.</p> <p>Andersson’s job is to set-up, repair, and build lecture demonstrations. Sometimes this involves building demos from scratch such as the pair of phonebooks with interlocking pages that requires the force of two heavy trucks to pull it apart. The phonebooks are one of Andersson’s favorites because it is fun to see confident students attempt to pull them apart. Other demonstrations, such as the vacuum bazooka have been modified by Andersson to be more effective. After seeing the bazooka in a publication on lecture demos he decided to build one, he created a rack for the pop cans so that they would be held in place and show the power of the ping pong ball as it comes out of the end of barrel. <br /> Demonstrations in general have a unique ability to get students involved in the classroom. Andersson says that he got interested in lecture demonstration during his time as a student at the University of Minnesota. “When I went here, I didn’t see a lot of demos. Many of the faculty weren’t using them and now they are.” Andersson is glad to see that has changed in recent years. “A lot of the faculty were pleasantly surprised to see how popular they were,” he said. Andersson said that students and teachers alike appreciate the break from the lecture format that the demonstrations provide. <br /> You can see many of School of Physics and Astronomy’s catalog of physics demonstrations as they have been filmed by Andersson and various student workers. Andersson says this resource is frequently used by groups outside the University that don’t have access to such an exhaustive supply of demos. He estimates the University has the second or third largest collection of lecture demonstrations in the US.</p> </div><br/><br/>More information: <a href="http://www.physics.umn.edu/resources/demos.html">http://www.physics.umn.edu/resources/demos.html</a> http://www.physics.umn.edu/about/news/3801/ Thu, 01 Sep 2011 00:00:00 CST