Featured Research

from universities, journals, and other organizations

Neutrinos are likely half as massive as previous estimates suggested

Date:
July 12, 2010
Source:
American Physical Society
Summary:
Neutrinos are so numerous that they affected the evolution of the universe in ways that provide an estimate of their masses.

These images represent numerical simulations comparing of the density of matter in a slice of the Universe with and without massive neutrinos. The two simulations started from the same initial conditions, with either massless neutrinos (left) or neutrinos with masses of 1.9 eV (right). In the massive neutrino case, matter is spread over a larger number of structures.
Credit: Shankar Agarwal and Hume Feldman, University of Kansas

Physicists have long known that neutrinos are among the lightest and most evasive fundamental particles. Now a survey of the galaxies is helping to narrow down the neutrino mass even further. It seems that neutrinos are at best half as massive as previously estimated, according to an analysis appearing July 12 in the journal Physical Review Letters.

Related Articles


The lower neutrino mass estimate is the result of a 3-dimensional survey of more than 700,000 galaxies called MegaZ DR7. Although neutrinos are very light and interact with matter very rarely, they are so numerous that they can have a significant effect on the evolution of the material distribution in the universe. The galactic distributions revealed in the MegaZ map appear consistent with a reduced upper limit of neutrino mass estimates.

There are restrictions on the information the map can provide, in part because there are three varieties of neutrinos (electron, muon, and tau neutrinos), each of which likely have different masses. As a result, MegaZ can only estimate the sum of the three neutrino masses. The galactic distribution suggests that the combined mass the three neutrino varieties is less than 0.28 electron volts. Although the survey doesn't offer a lower limit of neutrino masses, it's clear from the detection of neutrinos coming from our sun, as well as from laboratory experiments, that neutrinos have at least some mass.


Story Source:

The above story is based on materials provided by American Physical Society. Note: Materials may be edited for content and length.


Journal References:

  1. Shaun A. Thomas, Filipe B. Abdalla, and Ofer Lahav. Upper Bound of 0.28 eV on Neutrino Masses from the Largest Photometric Redshift Survey. Physical Review Letters, 105, 031301 DOI: 10.1103/PhysRevLett.105.031301
  2. Julien Lesgourgues. Galaxies weigh in on neutrinos. Physics, 3, 57 (2010) DOI: 10.1103/Physics.3.57

Cite This Page:

American Physical Society. "Neutrinos are likely half as massive as previous estimates suggested." ScienceDaily. ScienceDaily, 12 July 2010. <www.sciencedaily.com/releases/2010/07/100712115104.htm>.
American Physical Society. (2010, July 12). Neutrinos are likely half as massive as previous estimates suggested. ScienceDaily. Retrieved November 22, 2014 from www.sciencedaily.com/releases/2010/07/100712115104.htm
American Physical Society. "Neutrinos are likely half as massive as previous estimates suggested." ScienceDaily. www.sciencedaily.com/releases/2010/07/100712115104.htm (accessed November 22, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, November 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
Powered by NewsLook.com
Raw: Paralyzed Marine Walks With Robotic Braces

Raw: Paralyzed Marine Walks With Robotic Braces

AP (Nov. 21, 2014) Marine Corps officials say a special operations officer left paralyzed by a sniper's bullet in Afghanistan walked using robotic leg braces in a ceremony to award him a Bronze Star. (Nov. 21) Video provided by AP
Powered by NewsLook.com
British 'Bio-Bus' Is Powered By Human Waste

British 'Bio-Bus' Is Powered By Human Waste

Buzz60 (Nov. 21, 2014) British company GENeco debuted what its calling the Bio-Bus, a bus fueled entirely by biomethane gas produced from food scraps and sewage. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins