"Long before it's in the papers"
January 27, 2015


Galaxy-sized twist in time may explain cosmic conundrum

July 19, 2011
Courtesy of the University of Warwick
and World Science staff

A phys­i­cist has de­vised a gal­ax­y-sized so­lu­tion to one of the out­stand­ing puz­zles of sub­a­tom­ic phys­ics: why cer­tain sub­a­tom­ic pa­r­ti­cles dif­fer un­ex­pectedly from their “an­ti­mat­ter” forms.

An­ti­mat­ter pa­r­ti­cles are “twins” of the sub­a­tom­ic pa­r­ti­cles that make up or­di­nary mat­ter. Nor­mal pa­r­ti­cles and their “an­ti­pa­r­ti­cle” coun­ter­pa­rts have si­m­i­lar prop­er­ties ex­cept for op­po­site elec­tri­cal charge. One would ex­pect, then, that eve­ry pa­r­ti­cle and its an­ti­pa­r­ti­cle be­have the same way, ex­cept those diff­er­ences caused by the opposite charge. Un­for­tu­nate­ly, that’s not quite the case, and the lack of a clear rea­son why has an­noyed phys­i­cists for years.

An artist's il­lus­tra­tion shows the "grid" of space­time be­ing twisted by a turn­ing gal­axy. (U. of War­wick / Mark A Gar­lick)

Stud­ies of pa­r­ti­cles known as Kaons and B Mesons have found un­ex­plained dif­ferences in the way their mat­ter and an­ti­mat­ter ver­sions de­cay, or nat­u­rally dis­in­te­grate. The dis­crep­an­cy is called charge pa­r­ity vi­ola­t­ion or CP vi­ola­t­ion. It’s an awk­ward prob­lem, but some phys­i­cists feel solv­ing it might al­so lead to crack­ing a deeper mys­ter­y: why there is far less an­ti­mat­ter than mat­ter. It ap­pears more of the lat­ter sur­vived the birth of the uni­verse.

Phys­i­cist Mark Had­ley at the Uni­vers­ity of War­wick, U.K., now says he has found a test­a­ble ex­plana­t­ion for these pa­r­ti­cles’ strange be­hav­ior, show­ing that the “vi­ola­t­ion” is il­lu­so­ry. The an­swer seems to be that the rota­t­ion of our gal­axy changes the way sub­a­tom­ic pa­r­ti­cles break down, Had­ley ex­plains. 

The “asym­me­try,” he said, is “a con­se­quence of ga­lac­tic rota­t­ion twist­ing our lo­cal space time. If that is shown to be cor­rect then na­ture would be fun­da­men­tally sym­met­ric af­ter al­l.”

Ex­pe­ri­ments have found that—as Ein­stein pre­dict­ed—a mas­sive, spin­ning body twists space and time in its vicin­ity, “drag­ging” them around in an ef­fect akin to spin­ning a top in­side a cup of hon­ey. Time is af­fect­ed be­cause it is ul­ti­mately insepa­rable from space; as a re­sult, time moves at slightly dif­ferent rates un­der dif­ferent con­di­tions in the af­fect­ed ar­ea.

This can ex­plain the dif­ference in pa­r­ti­cle de­cay rates, Had­ley said: dif­ferent struc­tures with­in each sub­a­tom­ic pa­r­ti­cle ex­pe­ri­ence time dif­ferently de­pend­ing on wheth­er they are mat­ter or an­ti­mat­ter. Cu­ri­ous­ly, the av­er­age de­cay rates of the pa­r­ti­cles are the same; it’s the amount of varia­t­ion in these rates that dif­fers, some­thing that Had­ley main­tains is al­so a fac­tor of the ga­lac­tic mo­tion.

The beau­ty of the the­o­ry is that it can be tested, he said. Abun­dant da­ta al­ready ex­ists show­ing appa­rent CP vi­ola­t­ion in some de­cays; this can be re-checked for a pat­tern aligned with the ga­lac­tic rota­t­ion, he said. The find­ings could al­so open the door to ex­plaining why there is more mat­ter than an­ti­mat­ter, he added; the ear­li­est struc­tures in the uni­verse may have al­so gen­er­at­ed si­m­i­lar frame-dragging ef­fects, af­fect­ing the dis­tri­bu­tion of the two sub­stances.

Separate study find­ings announced earlier this month indi­cated that more ga­lax­ies spin coun­ter-clock­wise than clock­wise, poss­ibly ac­count­ing for some types of asym­metry in the uni­verse and hint­ing that the cos­mos itself may spin.

The new re­search is pub­lished in the jour­nal Euro­phys­ics Let­ters.

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A physicist has devised a galaxy-sized solution to one of the outstanding puzzles of subatomic physics: why certain subatomic particles differ unexpectedly from their “antimatter” versions. Antimatter particles are “twins” of the subatomic particles that make up ordinary matter. Normal particles and their “antiparticle” counterparts have similar properties except for opposite electrical charge. One would expect, then, that every particle and its antiparticle behave the same way, except for some actions that are opposite because of the opposite charge. Unfortunately, that’s not quite the case, and the lack of a clear reason why has annoyed physicists for years. Studies of particles known as Kaons and B Mesons have found unexplained differences in the way their matter and antimatter versions decay, or naturally disintegrate. The discrepancy is called “charge parity violation” or “CP violation.” It’s an awkward problem, but some physicists feel solving it might also lead to cracking a deeper mystery: why there is far less antimatter than matter. It appears more of the latter survived the birth of the universe. Physicist Mark Hadley at the University of Warwick, U.K., now said he has found a testable explanation for these particles’ strange behavior, showing that the “violation” is illusory. The answer seems to be that the rotation of our galaxy changes the way subatomic particles break down, Hadley explains. The “asymmetry,” he said, is “a consequence of galactic rotation twisting our local space time. If that is shown to be correct then nature would be fundamentally symmetric after all.” Experiments have found that—as Einstein predicted—a massive, spinning body twists space and time in its vicinity, “dragging” them around an effect akin to spinning a top inside a cup of honey. Time is affected because it is ultimately inseparable from space; as a result, time moves at slightly different rates under different conditions in the affected area. This can explain the difference in particle decay rates, Hadley said: different structures within each subatomic particle experience time differently depending on whether they are matter or antimatter. Curiously, the average decay rates of the particles are the same; it’s the amount of variation in these rates that differs, something that Hadley maintains is also a factor of the galactic motion. The beauty of the theory is that it can be tested, he said. Abundant data already exists showing apparent CP violation in some decays; this can be re-checked for a pattern aligned with the galactic rotation, he said. The findings could also open the door to explaining why there is more matter than antimatter, he added; the earliest structures in the universe may have also generated similar frame-dragging effects, affecting the distribution of the two substances. The new research is published in the journal Europhysics Letters.