1. International Session-Conference of SNP PSD RAS
“Physics of Fundamental Interactions”
BNO – 50
Current perspectives on multidimensional gravity search
at the LHC
Maria Savina
JINR, Dubna, Russia
June 08, 2017, Nalchik

2. Microscopic black holes in TeV scale gravity models

3. Production of microscopic BH in ultrarelativistic particle collisions
BH production and evolution stages:
Production cross section of multidimensional BH -
“a black disk”
(Mass and angular momentum) losses during horizon formation, suppression of cross sections by a few orders of magnitude.
BH evolution stages, spin-down phase, Hawking evaporation of BH. Criteria for semiclassical description. BH entropy.
GBF (microcanonical ensemble improvement,
emission “recoil” and repulsion from the
brane into the bulk etc.).
Mass loss and approaching to the MD threshold - possible SB/BH transition and models for QBHs.
Final Planck stage, different options for FS:
“usual” decay on a few “fragments”;
non-observable stable remnant;
B, L, B+L… non-conservation, violation of Lorentz
invariance
Thorn Conjecture
BH size must be less than all
characteristic scales under consideration

4. Kerr-Newman solution for neutral rotating BH in a flat multidimensional space
R.C. Myers and M.J. Perry, Ann. Phys. 72, 304, 1986
D-dimensional generalization of Kerr–Newman solution in Boyer–Lindquist coordinates GT
GRW (PDG) DL
BH mass
An angular momentum
Just numerical coefficients what are
important for LHC observability
An area of (n+2)-dimensional sphere surface
One of possible choices for MD

5. Main formulas for microscopic multidimensional BH
In ADD case:
(R.C. Myers and M.J. Perry,
Ann. Phys. 172, 304, 1986)
In RS1 plus condition:
as for ADD BHs, n=1.
Additional restrictions
by an entropy for BH of RS type
(xmin > 16)

6. BH production: geometrical cross section
Schwarzschild radius
: classical nonperturbative process
Then supposed, that all initial energy was
trapped under a horizon

7. Yoshino-Rychkov losses during BH formation
4D: R. Penrose, 1974
P. D. D’Eath and P. N. Payne,
PRD 46 (1992) 658, 675, 694
(4+n)D: D. M. Eardley and S. B. Giddings,
PRD 66 (2002) ,…
H. Yoshino and V. S. Rychkov,
PRD 71 (2005)

8. Production cross sections with losses
Production cross sections grow with
increasing of a number of ED n.
Losses grow with the BH mass (in dependence on multidimensional space-time geometry, the effect will be smaller for the RS-type BH).
Losses are minimal for BH with small masses produced near the fundamental gravity threshold (“quantum” BHs).

9. “Grey body” factors for BH emission
P. Kanti, J. March-Russell, I. Olasagasti K. Tamvakis, 2002; G. Duffy, C. Harris, P. Kanti and E. Winstanley, 2005;
M. Casals, P. Kanti and E. Winstanley, S. R. Dolan, ; D. Ida, K.-y. Oda and S. C. Park,
Hawking radiation: “democratic” decay blind to particle flavours
GBF modification: absorbtion coefficients for multidimensional Schroedinger type equation
A probability to pass a barrier is equal to a
probability for a particle to be reflected backward inside
a barrier in thermal equilibrium
In multidimensional case emission probability
is higher for particles with higher spins
graviton emission enchancement and redistribution of emission
fractions on the brane and into the bulk

10. BH entropy and criteria of semiclassical approach
SBH must be large enough to satisfy the BH thermal evolution condition
The lower limit of BH production that gives
xmin>4.1 (ADD) and
xmin>13 (RS1)
The energy of an each emitted d.o.f. is much smaller than MBH (dM/dN<<M)
Life time criteria for BHs (τM >>1)

11. Final state: SM vs typical BH decay spectra
Multi-jet and hard leptons events
High spherical
High energy and pT
SM Process
Experimental observables which
are sensitive to these features

12. 2017, 13 TeV
arXiv:
arXiv: [hep-ex] (21 Mar 2013)
JHEP 07 (2013) 178
2017, 13 TeV
arXiv:

13. Drell-Yan process and dijet angular distributions
Consistency with the LHC limits for ADD and RS1 scenarios, KK modes of graviton:
Drell-Yan process and dijet angular distributions

14. DY with contribution of the graviton KK modes
Effective four-fermion amplitude for KK modes exchange
ADD (HLZ parametrization)
Graviton resonances in the RS1 model
Effective four-fermion description has a limit of applicability
c (coupling constant)

15. The LHC results on ADD gravitons: Run II, dijet angular distributions
2.7 fb-1 of the Run II data (dijets) vs 20 fb-1of the Run I (dileptons, DY)
MS limits (HLZ):
2017, arXiv: v1, submit. to JHEP
Run I, virtual exchange
ΛT limits (GRW):
Run I, virtual exchange
Run II, dijet angular distributions
Dileptons 15

16. The LHC results on the narrow graviton resonances, RS1:
2016 data of the Run II plus 20 fb-1of the Run I, dileptons (DY)
Run I, dileptons
2016 data, PLB, V. 768 (2017), p. 57
Run II, dileptons

17. at the c.o.m. energy up to 14 TeV
To resume actual limits and result consistency on KK modes and BHs:
Minimal masses of semiclassical BHs are excluded up to 7.0 – 9.5 TeV in dependence on a
number of ED n and production model details.
Masses of quantum BHs are excluded up to 7.3 – 9.0 TeV (ADD, n=2–6) and up to 5.1 – 6.2
TeV (RS1, n=1). String balls are excluded with masses up to 8.0 – 8.5 TeV.
For KK modes of graviton in two different multidimensional scenarios, ADD and RS1 we
obtained lower mass limits of:
7.9 – 11.2 TeV in dependence on a number of ED n for the fundamental mass scale of
multidimensional gravity (MS or ΛT) in the ADD model;
1.46 TeV (c=0.01) and 3.11 TeV (c=0.1) for the mass of the first graviton resonance
MGKK (connected directly with MD) in the RS1 model.
Semiclassical BH production at the LHC lookes very unreal and inaccessible
at the c.o.m. energy up to 14 TeV
“Quantum” black holes etc.?

18. Near-threshold production of BH, “quantum” BHs and “string balls”
What next?
Near-threshold production of BH,
“quantum” BHs and “string balls”

19. Near-threshold BH production: model approaches
Multidimensional case. “Quantum” BH with “a memory” of initial states – final BH states
as color and electric charge representations.
Effective four-dimensional case. “Quantum” BH in the model with
copious hidden sectors interacting only gravitationally
Near-threshold transition black hole/ string ball, “boiling remnant” model
“Quantum” BH in 4D noncommutative space-time

20. “Quantum” BH : model approaches
- No BH-emission equilibrium
- Quantum effects (?)
- “A memory” of an initial state: color, charge, angular momentum
as for parton-initiator combination
For
– small angular momentum
No spherically symmetric final states !
2—3 particle FS, two particle state is the most probable
QBH production cross section – the “black disk” again
(GRW)

21. Near-threshold string ball / black hole transition, correspondence principle
L.~Susskind, hep-th/
G. T. Horowitz and J. Polchinski, PRD 55, 6189 (1997)
competitive regimes

22. String ball limits from the counting experiments
JHEP 07 (2013) 178
arXiv: [hep-ex]
RS type
ADD
String ball limits from the counting experiments
for a set of model parameters
(string coupling gs=0.4, fundamental scale Md
and string scale Ms)
Mmin is excluded from 5.5 to 5.7 TeV at 95 % CL.
QBH limits for ADD and RS type
Mmin is excluded from 4.7 to 6.2 TeV
for MD up to 5 TeV at 95 % CL.

23. Backup Slides

24. Black Hole & String Ball Event Generators
CHARYBDIS Version 1.0.3, MSTW2008lo68cl PDF
J. A. Frost, J. R. Gaunt, M. O.P. Sampaio, M. Casals, S. R. Dolan, M. A. Parker, and B. R. Webber, arXiv:
BlackMax Version 2.01, MSTW2008lo68cl PDF
De-Chang Dai, G. Starkman, D. Stojkovic, C. Issever, E. Rizvi, J. Tseng
“BlackMax: A black-hole event generator with rotation, recoil, split branes and brane tension”,
Phys.Rev. D77:076007, 2008, arXiv: v4
QBH Version 1.03, CTEQ6L PDF
D. Gingrich, “Quantum Black Holes with Charge, Colour, and Spin at the LHC”,
J. Phys. G37 (2010) , arXiv:

25. Хокинговское испарение многомерной ЧД

26. Total sum of the transverse energies of jets
Jets, photons and leptons,
ET > 50 GeV, missing ET > 50 GeV
ST = 2.5 TeV, N=9 (Run , Event )
ST = 1.1 TeV, N=10 (Run , Event )

27. Разные параметризации матричного элемента обмена ADD-гравитонами
HLZ: T. Han, J. Lykken, and R. Zhang, PRD 59, (1999)
GRW: G. Giudice, R. Rattazzi, and J.Wells, NPB 544, 3 (1999)
HLZ: (MS,n)
GRW: (ΛT)

28. Differential cross section for the DY process with ADD graviton contribution