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2 Sezen Sekmen FSU CERN-TR, 29 Temmuz 2009, CERN

3 OUTLUNE 1.Classical black holes 2.Large extra dimensions 3.Neo-classical black holes 4.Production of BHs at LHC 5.Observing BHs at LHC 6.Conclusions

4 “Black holes are where God divided by zero” – S. Wright Recipe for a black hole: Just squeeze any mass under a corresponding radius: Geometry of the spacetime near a BH can be found by solving Einstein’s equations for different conditions (charge, spin). Gravitation is so high near a BH such that even light cannot escape (Laplace). Schwazschild radius

5 BHs can decay via a quantum mechanical process…  Spacetime near a BH undergoes energy fluctuations where amount of energy created is determined by the uncertainity relation:  If for a certain time interval, created energy is high enough, virtual particle-antiparticle pairs are formed.  Because of strong gravitation near a BH, one of the particles falls into the BH, while other virtual particle flies to infinity.  Radiated particles have an expectation value of which resembles THERMAL radiation! ( K = surface gravity)  Particles falling into the BH have negative energy, BH looses mass and energy is conserved.  BH seems like a blackbody emitting radiation corresponding to a temperature of Which is called the Hawking temperature Hawking T H = · 2 ¼ = h c 2 18 ¼ 2 k GM BH ¢E¢ t ¸ ~ = 2 +- h b ¤ b i » ( exp ( 2 ¼! = · ) ¡ 1 ) ¡ 1

6 How to witness Hawking radiation? BHs radiate...but they can still absorb! Hawking radiation is visible only when BH is hotter then its surroundings: that is, hotter then the cosmic microwave background radiation which is ~3K. A BH radiating with a T H ~3K has a mass of ~10 23 kg and a Schwarzschild radius of ~10 -4 m. But the smallest mass that can form a BH by itself (determined by Tolman-Oppenheimer-Volkoff limit) is ~10 30 kg and such BHs would have a T H ~100 nK So let’s make them on Earth! Smaller BHs might be made by high energy collisions in particle accelerators. Imagine we try making a BH by collidng 2 protons: Smallest such BH to be made via collision would have a mass ~ GeV (10 -8 kg) and radius ~ m! So we should build an accelerator able to reach the Planck scale! (which would require a radius of ~10 6 km!)

7 This is not elegant And what is worse, this difference leads to quadratic divergencies in radiative corrections to the Higgs mass. where Λ is the scale at which the new physics appears.

8 Has anybody ever measured gravitaty below 1 mm? Might there be compactified large extra dimensions? Gravity must be wandering in large extra dimensions ! Savas Dimopoulos Nima Arkani-Hamed Gia Dvali Stanford proudly presents...

9 N. Arkani-Hamed, S. Dimopoulos, G. Dvali, Phys Lett. B429 (1998) 283, Phys Rev D (1999), I. Antonidis, N. Arkani-Hamed, S. Dimopolulos, G. Dvali, Phys Lett B 438 (1998) 257. Gravity might get increasingly strong at low distance scales. This could be possible if there exist n large, compactified extra dimensions with radius R ~ mm. Only gravity is allowed to wonder in the bulk of those LED, while SM fields are confined to the “3-brane”. Bulk components of gravity enhance the brane components and so gravity becomes stronger in the domain of the LED. Newton’s 3rd law is modified – and unification of all forces occurs at a much lower energy scale given by Now M (4+n) becomes the only fundamental scale LEP and Tevatron limits for M (4+n) : M (4+n) >1.3 for n =2, M (4+n) >0.3 for n = 6

10 Holes İn black Schwarzschild radius for a “4+n” black hole (from 4+n-dimensional Einstein equations): Schwarzschild radius for a 4-dimensional black hole: Comparing r s(4) and r s(4+n), we get: A “4+n” BH is BIGGER then a 4-dimensional BH with the same mass. r s ( 4 + n ) = 1 p ¼ M ( 4 + n ) µ M BH M ( 4 + n ) µ 8 ¡ (( n + 3 )= 2 ) n + 2 ¶¶ 1 n + 1 r s ( 4 ) = 1 M ( 4 ) µ M BH M ( 4 ) ¶ = 1 M 4 + n ) µ M BH M ( 4 + n ) ¶ 1 ( M ( 4 + n ) R ) n r s ( 4 ) < r s ( 4 + n ) < R

11 Holes İn black Energy defficiency!! NO BH!!! BH formed... EXPERIMENT2: Collide 2 partons with com E~TeV Impact parameter : b Spacetime with 4+n dimensions... Open n LED with radius R. EXPERIMENT1 : Collide 2 partons with com E~TeV Impact parameter : b Spacetime with 4 dimensions... b rs(4) R START... rs(4+n)

12 WARNING!!! This black hole will destroy itslf İ n seconds!!!

13 Hawking temperature Lifetime Higher-dimensional BHs are colder and they live longer. Holes İn black T ( 4 ) » M 2 ( 4 ) M BH T ( 4 + n ) » M ( 4 + n ) µ M ( 4 + n ) M BH ¶ 1 n + 1 ¿ ( 4 + n ) » 1 M ( 4 + n ) µ M BH M ( 4 + n ) ¶ n + 3 n + 1 ¿ ( 4 + n ) » 1 M ( 4 ) µ M BH M ( 4 ) ¶ 3

14 LHC? Can we produce them? Can we detect them?

15 Those who hunt BHs at LHC…  Dimopoulos, Landsberg, Phys. Rev. Lett. 87 (2001)  Akchurin, Damgov, Green, Kunori, Landsberg, Marrafino, Widal, Wenzel, Wu, CMS-IN 2004/07  Sekmen, Zeyrek, Eur. Phys. J. C38 (2005)  Gamsızkan, de Roeck, Sekmen, Zeyrek, CMS-AN 2006/088  Harris, Palmer, Parker, Richardson, Sabetfakhri, Webber (ATLAS), JHEP 0505 (2005) 053 (hep-ph/ )  Tanaka, Yamamura, Asai, Kanzaki, ATLAS, Eur. Phys. J. C41 (2005) (hep-ph/ )  Brett (ATLAS Cambridge group)  Betz, Bleicher, Harbach, Humanic, Koch, Stöcker, J. Phys G32 (2006) (hep-ph/

16 BH production – cross sections d L d M BH = 2 M BH s X a ; b Z 1 M 2 BH = s d x a x a f a ( x a ) f b ( M 2 BH sx a ) w h ere f i ( x i ) are PDF s.

17 BH production: cross sections with no corr. σ ~ 15 nb to 1 pb between M 4+n = 1 TeV to 5 TeV σ varies by %10 for n = 2 to 7

18 BH production: cross sections including F n F n can be calculated geometrically or numerically. Cross sections are drawn using the F n predicted by Yoshino & Ryckhov (YR) (Webber, hep- ph/ )

19 LHC as a BH factory Number of BHs produced at the LHC in electron or photon decay channels versus BH mass for the high luminosity case (100 fb -1 ).

20 Four phases of BH decay Balding: BH looses “hair”, that is, its quantum numbers and multiple momenta through gravitational radiation and Hawking emission, becoming a multidimensional, spinning (Kerr) BH. Spin down: BH sheds angular momentum by Hawking radiation and settles to a multidimensional Schwarzschild BH Schwarzschild: BH looses mass by Hawking radiation and decays until its Hawking temperature reaches ~M 4+n. Planck: MBH ~ M 4+n and BH belongs to the quantum gravity world and its fate is not known. It might possibly survive as a stable/semi-stable relic or it can evaporate completely into a few quanta.

21 Hawking radiation & multiplicity Landsberg, Dimopoulos, PRL 87, (2001) f : ° ux, N :mu l t i p l i c i t y, x = E = T H df d x » x 3 e x + c d N d E » 1 E df d E » x 2 e x + c h N i = ¿ M BH E À = M BH 2 T H U sea = 0. 5 f or B o l t zmans t a t i s t i cs. BHs decay democratically to all SM particles ¿ 1 E À = 1 T H R 1 0 d x x 2 e x + c R 1 0 d x 1 x x 2 e x + c = a T H

22 Corections to the BH blackbody spectrum  BHs are not perfect blackbodies. Hıgh curvature of spacetime near the horizon distorts the emission spectrum as (dN/dE) distorted = γdN/DE, where γ is the greybody factor. Distortion occurs more for particles emitted with low energies since at high energies particle wavelength > spacetime curvature. C. M. Harris, Ph.D. Thesis, hep-ph/ Greybody factors for fermionsIntegrated flux (greybody effects included)  Time variation of T H during the decay leads to a softer spectrum  Recoil of BH against the emitted particle also complicates the spectrum since the next decay occurs in a boosted frame.

23 BH lifetime Lifetime decreases with increasing n and increasing M BH /M 4+n. Landsberg Webber, hep-ph/ ¿ 4 + n » 1 M 4 + n µ M BH M 4 + n ¶ n + 3 n + 1

24 Reconstructing BHs at the LHC BH event generators:  TRUNOIR (Landsberg, Dimopoulos)  Unnamed MC by Japan group  Charybdis (Harris, Richardson, Webber )  Catfish (Cavaglia, Cremaldi, Godang, Summers) BLACK HOLE H. Gamsızkan, CMS, Charybdis M 4+n = 2, n = 3 ATLAS

25 BH signatures: High p T, spherical distr. Isotropic decay, hence large p T and spherical events: Gamsızkan et.al., CMS, Charybdis M 4+n = 2, n = 3, M BH = 4-14, sum(p T ) Tanaka et.al., ATLAS, Unnamed MC M 4+n = 1, n = 3, MBH = 1-14 Fox-Wolfram moment: Brett., ATLAS, Charybdis, n = 2 R 2 = H 2 = H 0 H i ´ X j ; k j p ¤ j jj p ¤ k j E 2 j P i ( cos Á j k )

26 BH signatures: High mult., jets/leptons ratio Gamsızkan et.al., CMS: M 4+n = 2, n = 3, M BH = 4-14, total multiplicity & jets/leptons ratio BHs have high multiplicity compared to SM events – and due to democratic decay, jets/leptons ratio ~ 5 : 1 Generic signal selection cuts: - Multiplicity > 4, isolatedlepton or photon multiplicity > 0 - Invariant mass > 2 TeV - Energy of each emitted particle < Minv/2 (to comply with kinematics) - Sphericity > 0.3

27 BH signatures: High MET Harris et al, ATLAS BHs have high multiplicity compared to SM events – and due to democratic decay, jets/leptons ratio ~ 5 : 1 Most analyses use MET > 100 GeV cut. Tanaka et.al., ATLAS, Unnamed MC M 4+n = 1, n = 3, M BH = 1-14

28 BH reach for 5σ observation Gamsızkan et.al., CMS, Charybdis Tanaka et.al., ATLAS, Unnamed MC For M BH = M 4+n

29 Reconstructing BH mass Tanaka et.al., ATLAS, Unnamed MC, n = 3, M BH = 1-14, solid line: S+B, cross-hatched: B only Gamsızkan et.al., CMS, Charybdis M 4+n = 2, n = 3, M BH = 4-14 Brett., ATLAS, Charybdis, n = 2 M 4+1 = 1TeVM 4+1 = 3TeVM 4+1 = 5TeVM 4+1 = 7TeV M BH = q ( P i p i ) 2

30 Heavy particles from BH decays Landsberg, PRL , TRUNOIR (gen level). M 4+n = 1, n = 3. W/Z 68.47GeV H GeV top GeV SS, MSc.Thesis, TRUNOIR + toy detector simulation. M 4+n = 2, n = 3, no b-tagging.

31 Reconstructing the Hawking spectrum Fit to Planck spectrum: Mean M BH = 4890 GeV Fit start: 750 GeV χ 2 / d.o.f. : Peak: 783 GeV T H = 464 GeV =1.83 X K T H (expected) = 674 GeV =7.82 X K SS, Zeyrek, EPJC38 (2006) 503, TRUNOIR + toy detector simulation. M 4+n = 2, n = 3 SS, MSc.Thesis, TRUNOIR + toy detector simulation. M 4+n = 2, n = 3, no b-tagging. We plotted all reconstructed particle energies (including heavy particles as top, W/Z, Higgs) in the spectra. Events with at least one lepton/photon were used.

32 Learning about spacetime… Take the logarithm of both sides of T H : l og ( T H ) = ¡ 1 n + 1 l og ( M BH ) + cons t Plot M BH vs. T H and fit to a line. Find n from the slope. Landsberg, Dimopoulos, PRL 87, (2001) Harris et al, ATLAS, Charybdis, M 4+n = 1, n = 2 But, including time variation leads to problems! t var: on t var: off Harris et al tried a method in which they determined the order of particles emitted, reconstructed MBH and HT after each emission.

33 Learning about spacetime… To find n: Plot the fraction p of events which emit particles with energy E cut = M BH /2 – d. This fraction is srongly dependent on n. To find M (4+n) : Make use of cross sections since they strongly depend on M (4+n) but their n-dependence is negligible. Harris et al, ATLAS, Charybdis, M 4+n = 1, n = 2 p l ower = k Z M BH = 2 E cu t P d E p upper = k Z 1 E cu t P d E Theoretical upper and lower limits on p: The final fit

34 Conclusions Spacetime may have n large extra dimensions with radius R ~ mm. In that case Planck scale will be reduced to ~TeV This may lead o creation of higher-dimensional BHs at the LHC with cross sections of ~nb – pb. BHs would decay immediately via Hawking radiation, which will lead to a significant signature By looking at BH decay products, we can construct the BH mass, Hawking temperature and new/heavy particles as Higgs. Looking at BHs, we might also extract n and M 4+n, and learn something about the structure of spacetime.

35 9 June 2008 Legendary LHC experiment creates higher- dimensional miniature black holes in proton collisions at CERN of Switzerland. Higher-dimensional Black Holes Radiate Higgs! Most Exotic Object of Cosmology Gives Birth to the Most Wanted Object of Particle Physics... GENEVA, JULY 13: Latest data coming from CERN (European Center for Nuclear REsearch) gives the good news that the long-hunted Higgs particle is finally observed. This discovery was through a most unusual experiment since the observed Higgs particles were formed via emissions from miniature extra-dimensional black holes produced in tunnels of the Large Hadron Collider (LHC) by high energetic proton-proton collisions. Higgs particle is very important for physics since it is the particle which is responsible for the masses of other particles. Yet despite all the prescise theoretical evidence Higgs particle was not observed until now since the earlier generation of particle accelerators did not have the sufficient collision energies to create the Higgs mass. Now this problem is solved with the completion of Large Hadron Collider which, with its 14 TeV center of mass energy, has initiated a new era of high energy physics experiments. It was again this high center of mass energy which enabled the production of black holes that live in higher dimensions of spacetime. Once formed, these black holes can decay through a quantum mechnical process, emitting all sorts of particles from the known Standard Model spectrum. As had already been predicted by the theory, almost one percent of the black hole decay products were found to be Higgs bosons. Although the signature of Higgs is quite clear among the data, physicists are still examining the marks of this curious particle to bring its properties to daylight. Detecting black holes at CERN proves that spacetime has seven dimensions. GENEVA, JULY 26: An ultimate physics experiment done at the Large Hadron Collider (LHC) of CERN (European Center for Nuclear Research) which produced first Earth-made black holes revaled important facts about the true structure of spacetime in small distance scales. Direct experimental information coming from the mass and decay temperature of black holes showed that spacetime has more then the four dimensions (length, width, height and time) that we perceive in everyday life. In recent years, many theoretical assumptions predicted the possibility for the existence of extra dimensions in spacetime, but till now these extra dimensions were not observed since firstly they open up at only very small distance scales and secondly, the particles from which objects of our daily encounter are made of are not able to penetrate the world of extra dimensions unless they reach very high energies. Theories also pointed out that existence of extra dimensions strengthened the gravitational interactions, which means, in the presence of extra dimensions, force of gravitational attractions would be stronger. Such an enhancement of the gravitational force was the phenomena which enabled the production of black holes on Earth. Black holes produced at the LHC live in extra dimensions and any data coming from them gives direct information on the structure of spacetime. Once formed, the extra- dimensional black holes decay through a quantum mechanical process called Hawking radiation abd the decay products could be studied APRIL 9, 2007 Stephen Hawking’s black hole radiation theory is proven experimentally at CERN after 34 years. CAMBRIDGE, 17 November : The Sweedish Royal Academy has announced that the Nobel Price in Physics for this year will go to Stephan W. Hawking for his theory of particle creation by black holes, which is also named “Hawking radiation” after its founder. Hawking’s theory of black hole decay was proved recently by the famous black hole production experiment at the LArge Hadron Collider (LHC) of CERN (European Center for Nuclear REsearch. Black holes are such objects from which even light cannot escape. Since lightspeed is the ultimate speed in universe, black holes are objects from which no escape is possible. However this idea was completely changed by a revolutionary paper by Hawking published in 1975 which suggested that black holes could emit radiation via a complicated quantum mechanical process. Briefly this idea states that spacetime near a black hole is not a classical vacuum. Energy fluctuations near a black hole creates particle-antiparticle pairs among which the antiparticle with negative energy enters the black hole while the particle with positive energy flies off to infinity. Negative energy of the antiparticle falling into the black hole reduces the mass of the black hole, therefore black hole seems to evaporate and emit particles. This phenomena was finaly observed in CERN after 33 years of its proposal in an experiment which created miniature black holes through high energy proton collisions. These black holes decayed immediately after their production, emitting a spectrum of high multiplicity of particle species. November 17, 20XX S. W. Hawking

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