Join us below at 11 A.M. Eastern time on Wednesday, July 4 for a live 30-minute online chat with physicist Michael Tuts of Columbia University, who will discuss an early-morning announcement from CERN, a Switzerland-based lab for particle physics, about the long-running search for the Higgs boson. We invite you to submit questions in advance in the comments section at the bottom of this page.
The Higgs particle, first hypothesized in the 1960s by physicist Peter Higgs and others, would help explain why elementary particles, such as quarks, have mass. Finding the Higgs—or ruling out its existence—was the prime motivation for building the Large Hadron Collider (LHC), where researchers collide protons traveling at nearly light-speed to create new particles.
[Click here to watch a Webcast of the announcement starting at 3 A.M. EDT Wednesday. The chat will take place later in chat box below.]
Michael Tuts, the U.S. operations program manager for the ATLAS detector at the LHC, will answer your questions during the chat about the Higgs, the LHC and what comes next in particle physics if indeed the Higgs has been found. We will turn on the capacity to log in to the chat box below around 10:50 A.M. EDT.
CHAT TRANSCRIPT
Robin Lloyd Hi everyone – I’m Robin Lloyd, Scientific American’s news editor. Thanks for all the early questions!
Marc Weyl Does this mean the end for String Theory? What now for the LHC as finding this is what it was built for?
EricROlson Can someone explain what is meant by a ‘5 sigma event’ and how it relates to identification of the Higgs?
Robin Lloyd Hi, Eric.
Robin Lloyd Good question.
Robin Lloyd We might try to start chat a little early. John Matson, Scientific American’s physics/math/space editor will host.
EricROlson Hi Robin. Also, for everyone else, I am Scientific American’s video editor.
Diane! If the Higgs Boson is responsible for giving other particles their mass, what gives the Higgs Boson its mass?
Robin Lloyd Good question, Diane, ha. One thing that amazes me about this finding is that the new particle is about 100 times mass of proton!
Robin Lloyd So all these years we hear about the proton. And in terms of mass, it’s ~100th the size of this new particle.
Hugo Alberto Gonzalez Hi all I would like to know whether this confirmed the existence of the Higgs particle, which follows after and whether they will study some
Robin Lloyd For those waiting for chat to start in full, our host will be John Matson, Scientific American’s space, math and physics editor
Robin Lloyd Hi Hugo. I’m SciAm’s news editor. My understanding is that this finding confirms existence of *a new particle. But more research is needed to confirm if this new particle is definitely the long-sought Higgs or mass particle
John Strubhart I would like to know why there is so much hype when the scientific process is far from complete for this discovery.
Robin Lloyd HI John Strubhart – the reason there is a lot of excitement is that it’s like discovering an elephant. It was there all the time. You still don’t know what the elephant does or exactly is, but damn, it’s an elephant!
Robin Lloyd Eric, sigma is just a stat that tells you how confident we are that an obtained figure from experiments is likely to have occurred by chance
Robin Lloyd Sigma is the standard (average) deviation of a population or probability distribution in statistics
sciam_live Hi all – John Matson here. I’m an associate editor at Scientific American. Happy Higgs day!
Chase Eckert Happy Higgs day!
Andy Semler Higgs Day! USA Independence Day! I’m getting married in 6 hours! What else can we pack into a single day?
Robin Lloyd Congrats, Andy! What a day to get married.
Chuck Cecil Congratulations to Peter Higgs! I am sure he is having the day of his life now.
sciam_live Chuck, did you see/hear him speak at the CERN seminar? Seemed very emotional
sciam_live Eric, to your question about 5 sigma, it means it’s a ~1-in-3.5 million chance the signal is really just background noise
Robin Lloyd Sigma indicates the probability that the result is random/occurred by chance. A higher sigma means less chance of that.
Chuck Cecil Is 5 Sigma the touchstone standard for research confirmation?
Robin Lloyd Chuck – in physics, yes, you need 5 sigmas for something to count as a valid discovery. Every field has its own custom with the probability it accepts for a random outcome cut-off. And I know at least in social sciences, there is more flexibility.
Treble Clef Caution: Discovery = monumental. But doesn’t fit the predictions precisely. Instead of pigeonholing, we should keep mind open 2 alt theories.
Andy Semler What would the alternate theories be?
Jaime Montoya Andy, supersymmetry is one of the alternative theories available.
Treble Clef Quantum Vacuum Intertial Mass Hypothesis. http://calphysics.org partly funded by NASA HQ as well. Full list of their papers. Instead of Higgs Field, ZPF. Instead of Higgs, Quantum Fluctuations: http://calphysics.org/sci_articles.html
Hugo Alberto Gonzalez All this excitement is so quiet, perhaps I am one of the few really excited or am I wrong? The magnitude of this event is so exciting.
EricROlson So sigma just tells us with confidence that we’ve found a particle, but not that its THE Higgs Boson?
sciam_live That’s correct, Eric.
CurseOfBenitez Regardless, this is terribly exciting.
Finn What other properties would the Higgs particle have that could be testable?
Jaime Montoya Eric, they were searching for a T. rex, instead they found a small alligator. It looks like the particle they found is NOT the Higgs boson at all.
Robin Lloyd Why do you say that, Jaime? I thought the results showed the particle IS behaving like Higgs in some ways.
Jaime Montoya Finn, the particle they found is too light (126Gev) to be the Higgs boson.
Jaime Montoya Robin, few months ago, nobody was expecting to find out the Higgs at 126 Gev range. That’s the point.
D Daro As I understand it, lighter than expected but still within the range.
John Parsons Actually, a Higgs in this mass range has been favored for a while.
Marc Weyl Heuer said it is ‘consistent’ with a Higgs.
sciam_live We’re having difficulty reaching Prof. Tuts at the moment but hope he’ll join us soon!
juanenlasala Whatever the results are this should be the time to erase the ‘God’ part from this research.
sciam_live Yes, the ‘God particle’ doesn’t do anyone any favors, I don’t think.
gikiian Once, my physics teacher told us that if the existence of the Higgs boson is verified, Mr. Higgs will get a Nobel Prize.
sciam_live @gikiian I think it’s very likely Higgs will get a Nobel prize. But hard to say who else would share it.
saavoss If this turns out to not be a Higgs boson, what are other possibilities for what it might be, and do these ‘alternate’ particles have a name?
Jaime Montoya Saavoss, you got it, looks like they found a different particle. Not the Higgs. The question is of course, what they found.
Treble Clef @saavoss Article by Cosmologist Marcus Chown on alternatives to Higgs http://calphysics.org/articles/chown2007.html
saavoss treble clef: Thank you!
Cecil Bullard How can the Higgs be so massive and decay just into two photons?
John Parsons The Higgs decay to two photons is mediated by a loop containing top quarks, which are heavy.
John Parsons The observed decays to two photons as well as to two Z bosons are expected for a Higgs, but the uncertainties are still large.
sciam_live Thanks, John Parsons, for that good info.
John Parsons So it is too early to reach a definitive conclusion; however all data so far are consistent with the predictions for the Higgs.
Kevin Bryant Mostly over my head, but I’ve been glad that I stayed up very late that night in the summer of ‘69 to watch the goings-on on the moon.
Robin Lloyd Hi Kevin, nice comparison.
Kevin Bryant And, I remember the teacher making us watch the first transatlantic transmission on TV in the early sixties. :-)
dasanil Why were there some comments yesterday that the Standard Model is excluded? What does that mean?
John Parsons The Standard Model could have been excluded given the amount of data; however, it was not since an excess was observed.
Jaime Montoya Mr. Parsons, why do they waste time looking in a higher Gev range instead of going directly to a lower range?
John Parsons It is necessary to search the entire range; the excess is at lower mass but there is no reason a priori for that to be true, therefore the search was more general; however now the higher masses have been ruled out by the data. Both experiments now seen an excess near 125 GeV.
Robin Lloyd I’m the news editor at Scientific American. Our scientist guest Mike Tuts is running a bit late, but I think we have another one participating now–physicist John Parsons of Columbia, who is answering questions. Thank you. At least, we suspect this :) 4 sigmas.
John Parsons I guess I have been ‘outed’; I am here at CERN. It has been an exciting day!
Robin Lloyd Thanks, Dr. Parsons.
Finn What will it take to verify that this excess is THE Higgs?
John Parsons Finn, we need to first verify the various decay modes. So far we have seen a few, but there are more that are predicted that will require more data.
sciam_live Prof. Parsons, your colleagues put on quite a viewing party at Columbia in the wee hours of the morn.
D Daro Yes, thank you Dr. Parsons
John Parsons Eventually we should also be able to test if the excess is due to a ‘scalar’ (i.e. spin 0) particle, a key prediction of the Standard Model. However that will take more data.
sciam_live Prof. Parsons, do you worry about the (small) mass difference between what ATLAS and CMS found?
John Parsons The CMS and ATLAS excesses are perfectly compatible given the current statistical errors.
Jaime Montoya Dr Parsons, do you think a 126 Gev Particle is responsible for a electroweak symmetry breaking?
Michael Kammer Dr. Parsons–At CERN, are there any guesses as to what the spin of the new boson is? I know they said they would probably have a good idea by the end of the year, but is there a gut feeling?
John Parsons We know from the 2photon decay that it has even integer spin (0. 2. ,,,,). The Higgs would be 0, but we cannot yet distinguish. A 126 GeV Higgs is sensible in the Standard Model but also in other models (eg. supersymmetry), so we need more data to tell the difference. However, what has been discovered is likely related to electroweak symmetry breaking; whether exactly as in the Standard Model or not. The other decay modes help determine the spin, but there are other observables (eg. angular distributions) that we can use with more stats.
Kevin Bryant Mere coincidence that ‘Jim’ Parsons plays Dr. Sheldon Cooper?? :-)
Robin Lloyd BTW, folks, John Parsons is part of the ATLAS experiment group. ATLAS is one of the 2 key experiments confirming particle.
Finn Do the experiments at CERN continue as before, just improving the precision of the result, or do the experiments morph into something new?
John Parsons Finn, both. We continue to look for many other things (e.g. direct evidence of dark matter) while also scrutinizing the new particle. Even if this is the Higgs, it leaves other open questions (e.g. dark matter, dark energy, matter-antimatter asymmetry, ….) The Higgs boson is not the end of the history. It is just the start.
Jaime Montoya Finn, we don’t know what 70 percent dark energy and 24 percent dark matter is made of, for instance
Robin Lloyd Dr. Parsons, do you think the evidence supports that the particle discovered IS the Higgs?
John Parsons The evidence so far ’looks like’ the Higgs, but the uncertainties are large and other theories (e.g. SUSY) would also look like this, so there is a lot of work to do.
Herb Cuthbertson What does this mean for future discoveries? If the various decay modes in future tests discover and confirm, where do we go from here?
John Parsons Herb, we cannot yet know. We first must investigate further if this new particle really behaves as predicted for the Standard Model Higgs in parallel with studying the new particle, we continue a very broad program looking for other new physics.
Chuck Cecil Is there a theoretical framework which would identify a particle is a dark particle if one was found? I am confused. How can you look for direct evidence for dark matter when we have no idea what it is?
John Parsons Chuck, we can try create dark matter particles in our collisions, in which case we can try learn what it is.
Jaime Montoya Chuck, that’s the point, as today, dark energy+dark matter is a total mystery.
Robin Lloyd Hi all – I’m SciAm’s news editor. We are delighted that physicist John Parsons is fielding questions for chatters today. Dr. Parsons works on the ATLAS experiment at CERN, one of the experiments that discovered the new particle. We also have some other SciAm editors in the room – Philip Yam, John Matson (at sciam_live), Eric Olson.
Andy Semler Is the media reporting particularly accurate in representing this discovery?
sciam_live Good Q, Andy – I’m part of the media, but I’ve been overall impressed with quality of reporting.
John Parsons Andy, the media is doing a pretty good job I think; of course, it is complicated to communicate a technical subject.
Marc Weyl The misnomer ‘God’ particle has not helped the media.
John Parsons The misnomer is not popular among physicists!
philipyam Unfortunately, god particle really resonates with the public.
Michael Kammer I’m a bigger fan of the original name, the god**** particle!
dasanil Many stories about this say that the Higgs boson provides gravity. Does Higgs explain only inertial properties of mass, but also gravitational?
John Parsons The higgs does NOT provide gravity; it gives mass to particles (eg. the electron). Gravity is not understood within the SM, one of its limitations. The mass is OK for the Standard Model and also lies within expected range for SUSY (supersymmetry).
rf What property of the Higgs can be tested to determine if Supersymmetry theories are valid?
Jaime Montoya rf, the problem with SUSY theory is there is not evidence of new particles above 126 gev range as predicted.
_le_idiot The energy level 125 suggests FermiLab Tevatron has evidence. Was the LHC overbuilt?
John Parsons Only the LHC can definitively discover the particle, and even more important study its properties to see if it is indeed the Standard Model Higgs.
D Daro How many Higgs does SUSY predict?
John Parsons If SUSY is valid, there are several more Higgs bosons (as well as many other new particles to discover). Minimal SUSY predicts 5 Higgs bosons with varying properties (including some that are electrically charged).
JamesC I understand the cosmological constant is an integration constant, i.e really a constant and it could account for dark energy. Is that correct?
John Parsons The cosmological constant could be dark energy, but that is far from certain at this point.
Jaime Montoya D Daro, SUSY predicts that every single particle has a super mass equivalent.
Michael Kammer Dr. Parsons, can you describe the atmosphere at CERN right now? I imagine it somewhat akin to being in the city of the superbowl winners?
John Parsons Euphoria! (and an excitement to see what additional data will teach us).
saavoss Oh man,… to be a CERN right now…..
philipyam The whole Higgs discovery reminds me of the top quark discovery in the 90s: two rounds of announcements.
Robin Lloyd Good historical perspective, Phil (Phil is SciAm’s managing editor for online and knows a lot about physics. He was SciAm’s physics editor for several years.).
John Parsons Yes there are some similarities to top quark discovery in that ‘hints’ appeared early and then were confirmed with more data later.
rf Articles hint that some properties of the discovered particle are NOT as the Standard Model predicted. What are these and what are the ramifications?
John Parsons With the current data, everything is consistent with Standard Model Higgs; however, the uncertainties are large and so it is early days.
Jaime Montoya rf, basically the particle they found (excellent job, btw!) is lighter than expected.
Chris Atteridge Will the future full power of the LHC (7 TeV beams) be able to determine if this new particle is elementary or not?
John Parsons Full LHC energy will indeed be important to study this new particle in detail (as well as providing a lot of other advantages).
D Daro Dr Parsons, when will they run at full energy, 2014?
Jaime Montoya Chris, at that level, the antropic principle and conscience definition will be key players
sciam_live Thanks, folks, for an interesting exchange. I’m off to get some rest. Want to thank Prof. Parsons, our impromptu guest!
rf Does the discovery of the Higgs bolster String Theory? Does String theory make any additional predictions about the Higgs?
John Parsons String theory ’needs’ SUSY and SUSY ’needs’ a light Higgs, so the discovery is not bad for strings (but not very definitive). Full energy is scheduled for 2015, after a 2 yr shutdown after the end of this year.
philipyam Full energy in 2015: quick, someone update the Wikipedia entry ; )
Robin Lloyd OK, we were supposed to end this chat at 11:30 am, but let’s keep chatting until 11:45? Then we will shut down the chat.
John Parsons Sounds good.
saavoss I am not an academic…sorry, but what is ‘SUSY’?
Jaime Montoya saavoss, SUSY = supersymmetric theory.
John Parsons Supersymmetry is a theoretically proposed symmetry of the universe that would help explain some open questions (but is unproven).
philipyam SUSY suggests that elementary particles have partner particles that are much heavier….in other words, every boson has a corresponding fermion.
Marc Weyl What is needed to see if this is the Standard Model Higgs vs. SUSY Higgs?
John Parsons To see if this is Standard Model or SUSY Higgs we need to measure its decays precisely. Also we need to continue to look for other particles (including other Higgs) predicted by SUSY.
_le_idiot Symmetry hasn’t been the rule, however.
D Daro Dr. Parsons, at the current energies do you anticipate seeing possible other Higgs or is the sense that full power is needed?
John Parsons It is not yet clear whether we have enough energy now; certainly going to full energy in ~2 years will be very important.
EricROlson Prof. Parson, what would it take to say with absolute certainty that the Higgs exists? Is there a benchmark or just increasing probability?
John Parsons There is no ‘absolute certainty’ in science; everything has a level of uncertainty (that we work hard to quantify).
Dan Arel How long before Louisiana makes the Higgs boson illegal?
D Daro lol at that one Dan.
dasanil Does the Higgs mechanism involve three way intersection between Higgs boson, the force boson (e.g. photon) and the particle that has mass?
Jaime Montoya Dr. Parsons, there is still a chance that Einstein’s relative theory is wrong? Or definitely this is not an option?
John Parsons We have no evidence relativity is incorrect.
John Parsons SUSY predicts a partner of all the particles we know; since we have not observed them, they must be massive (if SUSY is correct).
Andy Semler Thank you very much for hosting this chat, and to all the experts.
Marc Weyl Yes, Thank You! And to SciAm too!
D Daro Thank you, Dr. Parsons and SciAm.
John Parsons Good evening from Geneva!
Robin Lloyd Thanks so much to Dr. John Parsons of Columbia University and the ATLAS experiment, and all our guests.
Michael Kammer And thanks to 50 years of scientists for working tirelessly towards this.
saavoss Just want to say Thank you to Dr. Parsons. I’ve enjoyed this chat immensely and learned so much. I know that I still have much to learn.
Treble Clef Thanks for you time Dr. Parsons
Jaime Montoya Thank,s Dr Parson, SciAm and all you guys, very exciting day!
philipyam Thanks to Dr. Parsons for a great job!
The Higgs particle, first hypothesized in the 1960s by physicist Peter Higgs and others, would help explain why elementary particles, such as quarks, have mass. Finding the Higgs—or ruling out its existence—was the prime motivation for building the Large Hadron Collider (LHC), where researchers collide protons traveling at nearly light-speed to create new particles.
[Click here to watch a Webcast of the announcement starting at 3 A.M. EDT Wednesday. The chat will take place later in chat box below.]
Michael Tuts, the U.S. operations program manager for the ATLAS detector at the LHC, will answer your questions during the chat about the Higgs, the LHC and what comes next in particle physics if indeed the Higgs has been found. We will turn on the capacity to log in to the chat box below around 10:50 A.M. EDT.
CHAT TRANSCRIPT
Robin Lloyd Hi everyone – I’m Robin Lloyd, Scientific American’s news editor. Thanks for all the early questions!
Marc Weyl Does this mean the end for String Theory? What now for the LHC as finding this is what it was built for?
EricROlson Can someone explain what is meant by a ‘5 sigma event’ and how it relates to identification of the Higgs?
Robin Lloyd Hi, Eric.
Robin Lloyd Good question.
Robin Lloyd We might try to start chat a little early. John Matson, Scientific American’s physics/math/space editor will host.
EricROlson Hi Robin. Also, for everyone else, I am Scientific American’s video editor.
Diane! If the Higgs Boson is responsible for giving other particles their mass, what gives the Higgs Boson its mass?
Robin Lloyd Good question, Diane, ha. One thing that amazes me about this finding is that the new particle is about 100 times mass of proton!
Robin Lloyd So all these years we hear about the proton. And in terms of mass, it’s ~100th the size of this new particle.
Hugo Alberto Gonzalez Hi all I would like to know whether this confirmed the existence of the Higgs particle, which follows after and whether they will study some
Robin Lloyd For those waiting for chat to start in full, our host will be John Matson, Scientific American’s space, math and physics editor
Robin Lloyd Hi Hugo. I’m SciAm’s news editor. My understanding is that this finding confirms existence of *a new particle. But more research is needed to confirm if this new particle is definitely the long-sought Higgs or mass particle
John Strubhart I would like to know why there is so much hype when the scientific process is far from complete for this discovery.
Robin Lloyd HI John Strubhart – the reason there is a lot of excitement is that it’s like discovering an elephant. It was there all the time. You still don’t know what the elephant does or exactly is, but damn, it’s an elephant!
Robin Lloyd Eric, sigma is just a stat that tells you how confident we are that an obtained figure from experiments is likely to have occurred by chance
Robin Lloyd Sigma is the standard (average) deviation of a population or probability distribution in statistics
sciam_live Hi all – John Matson here. I’m an associate editor at Scientific American. Happy Higgs day!
Chase Eckert Happy Higgs day!
Andy Semler Higgs Day! USA Independence Day! I’m getting married in 6 hours! What else can we pack into a single day?
Robin Lloyd Congrats, Andy! What a day to get married.
Chuck Cecil Congratulations to Peter Higgs! I am sure he is having the day of his life now.
sciam_live Chuck, did you see/hear him speak at the CERN seminar? Seemed very emotional
sciam_live Eric, to your question about 5 sigma, it means it’s a ~1-in-3.5 million chance the signal is really just background noise
Robin Lloyd Sigma indicates the probability that the result is random/occurred by chance. A higher sigma means less chance of that.
Chuck Cecil Is 5 Sigma the touchstone standard for research confirmation?
Robin Lloyd Chuck – in physics, yes, you need 5 sigmas for something to count as a valid discovery. Every field has its own custom with the probability it accepts for a random outcome cut-off. And I know at least in social sciences, there is more flexibility.
Treble Clef Caution: Discovery = monumental. But doesn’t fit the predictions precisely. Instead of pigeonholing, we should keep mind open 2 alt theories.
Andy Semler What would the alternate theories be?
Jaime Montoya Andy, supersymmetry is one of the alternative theories available.
Treble Clef Quantum Vacuum Intertial Mass Hypothesis. http://calphysics.org partly funded by NASA HQ as well. Full list of their papers. Instead of Higgs Field, ZPF. Instead of Higgs, Quantum Fluctuations: http://calphysics.org/sci_articles.html
Hugo Alberto Gonzalez All this excitement is so quiet, perhaps I am one of the few really excited or am I wrong? The magnitude of this event is so exciting.
EricROlson So sigma just tells us with confidence that we’ve found a particle, but not that its THE Higgs Boson?
sciam_live That’s correct, Eric.
CurseOfBenitez Regardless, this is terribly exciting.
Finn What other properties would the Higgs particle have that could be testable?
Jaime Montoya Eric, they were searching for a T. rex, instead they found a small alligator. It looks like the particle they found is NOT the Higgs boson at all.
Robin Lloyd Why do you say that, Jaime? I thought the results showed the particle IS behaving like Higgs in some ways.
Jaime Montoya Finn, the particle they found is too light (126Gev) to be the Higgs boson.
Jaime Montoya Robin, few months ago, nobody was expecting to find out the Higgs at 126 Gev range. That’s the point.
D Daro As I understand it, lighter than expected but still within the range.
John Parsons Actually, a Higgs in this mass range has been favored for a while.
Marc Weyl Heuer said it is ‘consistent’ with a Higgs.
sciam_live We’re having difficulty reaching Prof. Tuts at the moment but hope he’ll join us soon!
juanenlasala Whatever the results are this should be the time to erase the ‘God’ part from this research.
sciam_live Yes, the ‘God particle’ doesn’t do anyone any favors, I don’t think.
gikiian Once, my physics teacher told us that if the existence of the Higgs boson is verified, Mr. Higgs will get a Nobel Prize.
sciam_live @gikiian I think it’s very likely Higgs will get a Nobel prize. But hard to say who else would share it.
saavoss If this turns out to not be a Higgs boson, what are other possibilities for what it might be, and do these ‘alternate’ particles have a name?
Jaime Montoya Saavoss, you got it, looks like they found a different particle. Not the Higgs. The question is of course, what they found.
Treble Clef @saavoss Article by Cosmologist Marcus Chown on alternatives to Higgs http://calphysics.org/articles/chown2007.html
saavoss treble clef: Thank you!
Cecil Bullard How can the Higgs be so massive and decay just into two photons?
John Parsons The Higgs decay to two photons is mediated by a loop containing top quarks, which are heavy.
John Parsons The observed decays to two photons as well as to two Z bosons are expected for a Higgs, but the uncertainties are still large.
sciam_live Thanks, John Parsons, for that good info.
John Parsons So it is too early to reach a definitive conclusion; however all data so far are consistent with the predictions for the Higgs.
Kevin Bryant Mostly over my head, but I’ve been glad that I stayed up very late that night in the summer of ‘69 to watch the goings-on on the moon.
Robin Lloyd Hi Kevin, nice comparison.
Kevin Bryant And, I remember the teacher making us watch the first transatlantic transmission on TV in the early sixties. :-)
dasanil Why were there some comments yesterday that the Standard Model is excluded? What does that mean?
John Parsons The Standard Model could have been excluded given the amount of data; however, it was not since an excess was observed.
Jaime Montoya Mr. Parsons, why do they waste time looking in a higher Gev range instead of going directly to a lower range?
John Parsons It is necessary to search the entire range; the excess is at lower mass but there is no reason a priori for that to be true, therefore the search was more general; however now the higher masses have been ruled out by the data. Both experiments now seen an excess near 125 GeV.
Robin Lloyd I’m the news editor at Scientific American. Our scientist guest Mike Tuts is running a bit late, but I think we have another one participating now–physicist John Parsons of Columbia, who is answering questions. Thank you. At least, we suspect this :) 4 sigmas.
John Parsons I guess I have been ‘outed’; I am here at CERN. It has been an exciting day!
Robin Lloyd Thanks, Dr. Parsons.
Finn What will it take to verify that this excess is THE Higgs?
John Parsons Finn, we need to first verify the various decay modes. So far we have seen a few, but there are more that are predicted that will require more data.
sciam_live Prof. Parsons, your colleagues put on quite a viewing party at Columbia in the wee hours of the morn.
D Daro Yes, thank you Dr. Parsons
John Parsons Eventually we should also be able to test if the excess is due to a ‘scalar’ (i.e. spin 0) particle, a key prediction of the Standard Model. However that will take more data.
sciam_live Prof. Parsons, do you worry about the (small) mass difference between what ATLAS and CMS found?
John Parsons The CMS and ATLAS excesses are perfectly compatible given the current statistical errors.
Jaime Montoya Dr Parsons, do you think a 126 Gev Particle is responsible for a electroweak symmetry breaking?
Michael Kammer Dr. Parsons–At CERN, are there any guesses as to what the spin of the new boson is? I know they said they would probably have a good idea by the end of the year, but is there a gut feeling?
John Parsons We know from the 2photon decay that it has even integer spin (0. 2. ,,,,). The Higgs would be 0, but we cannot yet distinguish. A 126 GeV Higgs is sensible in the Standard Model but also in other models (eg. supersymmetry), so we need more data to tell the difference. However, what has been discovered is likely related to electroweak symmetry breaking; whether exactly as in the Standard Model or not. The other decay modes help determine the spin, but there are other observables (eg. angular distributions) that we can use with more stats.
Kevin Bryant Mere coincidence that ‘Jim’ Parsons plays Dr. Sheldon Cooper?? :-)
Robin Lloyd BTW, folks, John Parsons is part of the ATLAS experiment group. ATLAS is one of the 2 key experiments confirming particle.
Finn Do the experiments at CERN continue as before, just improving the precision of the result, or do the experiments morph into something new?
John Parsons Finn, both. We continue to look for many other things (e.g. direct evidence of dark matter) while also scrutinizing the new particle. Even if this is the Higgs, it leaves other open questions (e.g. dark matter, dark energy, matter-antimatter asymmetry, ….) The Higgs boson is not the end of the history. It is just the start.
Jaime Montoya Finn, we don’t know what 70 percent dark energy and 24 percent dark matter is made of, for instance
Robin Lloyd Dr. Parsons, do you think the evidence supports that the particle discovered IS the Higgs?
John Parsons The evidence so far ’looks like’ the Higgs, but the uncertainties are large and other theories (e.g. SUSY) would also look like this, so there is a lot of work to do.
Herb Cuthbertson What does this mean for future discoveries? If the various decay modes in future tests discover and confirm, where do we go from here?
John Parsons Herb, we cannot yet know. We first must investigate further if this new particle really behaves as predicted for the Standard Model Higgs in parallel with studying the new particle, we continue a very broad program looking for other new physics.
Chuck Cecil Is there a theoretical framework which would identify a particle is a dark particle if one was found? I am confused. How can you look for direct evidence for dark matter when we have no idea what it is?
John Parsons Chuck, we can try create dark matter particles in our collisions, in which case we can try learn what it is.
Jaime Montoya Chuck, that’s the point, as today, dark energy+dark matter is a total mystery.
Robin Lloyd Hi all – I’m SciAm’s news editor. We are delighted that physicist John Parsons is fielding questions for chatters today. Dr. Parsons works on the ATLAS experiment at CERN, one of the experiments that discovered the new particle. We also have some other SciAm editors in the room – Philip Yam, John Matson (at sciam_live), Eric Olson.
Andy Semler Is the media reporting particularly accurate in representing this discovery?
sciam_live Good Q, Andy – I’m part of the media, but I’ve been overall impressed with quality of reporting.
John Parsons Andy, the media is doing a pretty good job I think; of course, it is complicated to communicate a technical subject.
Marc Weyl The misnomer ‘God’ particle has not helped the media.
John Parsons The misnomer is not popular among physicists!
philipyam Unfortunately, god particle really resonates with the public.
Michael Kammer I’m a bigger fan of the original name, the god**** particle!
dasanil Many stories about this say that the Higgs boson provides gravity. Does Higgs explain only inertial properties of mass, but also gravitational?
John Parsons The higgs does NOT provide gravity; it gives mass to particles (eg. the electron). Gravity is not understood within the SM, one of its limitations. The mass is OK for the Standard Model and also lies within expected range for SUSY (supersymmetry).
rf What property of the Higgs can be tested to determine if Supersymmetry theories are valid?
Jaime Montoya rf, the problem with SUSY theory is there is not evidence of new particles above 126 gev range as predicted.
_le_idiot The energy level 125 suggests FermiLab Tevatron has evidence. Was the LHC overbuilt?
John Parsons Only the LHC can definitively discover the particle, and even more important study its properties to see if it is indeed the Standard Model Higgs.
D Daro How many Higgs does SUSY predict?
John Parsons If SUSY is valid, there are several more Higgs bosons (as well as many other new particles to discover). Minimal SUSY predicts 5 Higgs bosons with varying properties (including some that are electrically charged).
JamesC I understand the cosmological constant is an integration constant, i.e really a constant and it could account for dark energy. Is that correct?
John Parsons The cosmological constant could be dark energy, but that is far from certain at this point.
Jaime Montoya D Daro, SUSY predicts that every single particle has a super mass equivalent.
Michael Kammer Dr. Parsons, can you describe the atmosphere at CERN right now? I imagine it somewhat akin to being in the city of the superbowl winners?
John Parsons Euphoria! (and an excitement to see what additional data will teach us).
saavoss Oh man,… to be a CERN right now…..
philipyam The whole Higgs discovery reminds me of the top quark discovery in the 90s: two rounds of announcements.
Robin Lloyd Good historical perspective, Phil (Phil is SciAm’s managing editor for online and knows a lot about physics. He was SciAm’s physics editor for several years.).
John Parsons Yes there are some similarities to top quark discovery in that ‘hints’ appeared early and then were confirmed with more data later.
rf Articles hint that some properties of the discovered particle are NOT as the Standard Model predicted. What are these and what are the ramifications?
John Parsons With the current data, everything is consistent with Standard Model Higgs; however, the uncertainties are large and so it is early days.
Jaime Montoya rf, basically the particle they found (excellent job, btw!) is lighter than expected.
Chris Atteridge Will the future full power of the LHC (7 TeV beams) be able to determine if this new particle is elementary or not?
John Parsons Full LHC energy will indeed be important to study this new particle in detail (as well as providing a lot of other advantages).
D Daro Dr Parsons, when will they run at full energy, 2014?
Jaime Montoya Chris, at that level, the antropic principle and conscience definition will be key players
sciam_live Thanks, folks, for an interesting exchange. I’m off to get some rest. Want to thank Prof. Parsons, our impromptu guest!
rf Does the discovery of the Higgs bolster String Theory? Does String theory make any additional predictions about the Higgs?
John Parsons String theory ’needs’ SUSY and SUSY ’needs’ a light Higgs, so the discovery is not bad for strings (but not very definitive). Full energy is scheduled for 2015, after a 2 yr shutdown after the end of this year.
philipyam Full energy in 2015: quick, someone update the Wikipedia entry ; )
Robin Lloyd OK, we were supposed to end this chat at 11:30 am, but let’s keep chatting until 11:45? Then we will shut down the chat.
John Parsons Sounds good.
saavoss I am not an academic…sorry, but what is ‘SUSY’?
Jaime Montoya saavoss, SUSY = supersymmetric theory.
John Parsons Supersymmetry is a theoretically proposed symmetry of the universe that would help explain some open questions (but is unproven).
philipyam SUSY suggests that elementary particles have partner particles that are much heavier….in other words, every boson has a corresponding fermion.
Marc Weyl What is needed to see if this is the Standard Model Higgs vs. SUSY Higgs?
John Parsons To see if this is Standard Model or SUSY Higgs we need to measure its decays precisely. Also we need to continue to look for other particles (including other Higgs) predicted by SUSY.
_le_idiot Symmetry hasn’t been the rule, however.
D Daro Dr. Parsons, at the current energies do you anticipate seeing possible other Higgs or is the sense that full power is needed?
John Parsons It is not yet clear whether we have enough energy now; certainly going to full energy in ~2 years will be very important.
EricROlson Prof. Parson, what would it take to say with absolute certainty that the Higgs exists? Is there a benchmark or just increasing probability?
John Parsons There is no ‘absolute certainty’ in science; everything has a level of uncertainty (that we work hard to quantify).
Dan Arel How long before Louisiana makes the Higgs boson illegal?
D Daro lol at that one Dan.
dasanil Does the Higgs mechanism involve three way intersection between Higgs boson, the force boson (e.g. photon) and the particle that has mass?
Jaime Montoya Dr. Parsons, there is still a chance that Einstein’s relative theory is wrong? Or definitely this is not an option?
John Parsons We have no evidence relativity is incorrect.
John Parsons SUSY predicts a partner of all the particles we know; since we have not observed them, they must be massive (if SUSY is correct).
Andy Semler Thank you very much for hosting this chat, and to all the experts.
Marc Weyl Yes, Thank You! And to SciAm too!
D Daro Thank you, Dr. Parsons and SciAm.
John Parsons Good evening from Geneva!
Robin Lloyd Thanks so much to Dr. John Parsons of Columbia University and the ATLAS experiment, and all our guests.
Michael Kammer And thanks to 50 years of scientists for working tirelessly towards this.
saavoss Just want to say Thank you to Dr. Parsons. I’ve enjoyed this chat immensely and learned so much. I know that I still have much to learn.
Treble Clef Thanks for you time Dr. Parsons
Jaime Montoya Thank,s Dr Parson, SciAm and all you guys, very exciting day!
philipyam Thanks to Dr. Parsons for a great job!
